通讯机构：
[Gu, WL ] U;Univ South China, Sch Civil Engn, Hengyang, Peoples R China.
关键词：
Solar radiant energy;Non-uniform heat flow;Buoyancy;Secondary flow;Thermal performance
摘要：
Under the focusing characteristics of parabolic trough solar collectors, enhancing secondary flow intensity and shifting the secondary flow vortex center towards the bottom of the absorber can extend the lifespan of the absorber and improve thermal performance. This study combines the Monte Carlo Ray Tracing method (MCRT) and the Finite Volume Method (FVM) to investigate the fluid flow and heat transfer characteristics inside the absorber under non-uniform thermal boundary conditions. The effects of inlet flow rate (Vin), inlet temperature (Tin), and protrusion structures on the secondary flow vortex position are examined. Through numerical analysis, secondary flow intensity (Se), heat transfer coefficient (h), Nusselt number (Nu), and friction factor (f) are calculated. The results show that increasing the Tin significantly enhances secondary flow intensity, thereby improving heat transfer within the absorber. Specifically, when Tin increases from 400.15 to 600.15 K, Se increases by a factor of 7.87, while h increases by 98.96%. Increasing the Vin shifts the secondary flow vortex downward, enhancing heat transfer at the bottom of the absorber. For example, when Vin increases from 100 to 200 L min−1, Se remains largely unchanged, while h increases by 44.68%. Compared to semi-cylindrical protrusions, tetrahedral protrusions are more effective at suppressing the upward shift of the secondary flow vortex, reducing velocity losses caused by fluid-wall interaction, and achieving better heat transfer enhancement. Under conditions of Tin = 500.15 K and Vin = 100 L min−1, the Nu increases by 14.6% for tetrahedral protrusions and 7.3% for semi-cylindrical protrusions, while the f increases by 12.3% and 10.9%, respectively, compared to the smooth absorber.
作者机构：
[Fan, Chenzhou; Wang, Tianlin] Univ South China, Sch Civil Engn, Hengyang 421001, Peoples R China.;[Xu, Feng; Xu, F; Guo, Changqing] Univ South China, Sch Math & Phys, Hengyang 421001, Peoples R China.
通讯机构：
[Xu, F ] U;Univ South China, Sch Math & Phys, Hengyang 421001, Peoples R China.
关键词：
Foundation excitation;Gap constraint;Fluid-conveying pipe;Impact vibration
摘要：
In practical engineering, the unilateral gap constraint impact vibration in fluid-conveying pipes is a critical concern, often arising from constraint loosening or the presence of barriers around the pipe. These factors can significantly affect the service life and safety reliability of the pipes. A tension and compression anisotropy spring with rapidly increasing restoring force in compression but almost zero restoring force in tension is proposed to simulate the unilateral gap constraint, model a fluid-conveying pipe with a Pfluger column. Its reliability is also verified based on the bifurcation phase diagram comparison between the small and large stiffness conditions. Subsequently, we establish a vibration mechanics analysis model for the cantilever fluid-conveying pipe under foundation excitation to assess the effects of basic excitation frequency, fluid velocity, distributed follower force, position coordinate of unilateral gap constraint, and the viscoelastic coefficient on the impact vibration stability of the fluid-conveying pipe. Our findings reveal that when the period-doubling bifurcation sequence is interrupted by Bare-grazing bifurcation, the system directly transitions into chaotic vibration or induces a new period-doubling bifurcation sequence, followed by re-entry into chaotic vibration. These results provide valuable insights into the intricate dynamics of fluid-conveying pipes under foundation excitation, offering a deeper understanding of the impact of various parameters on the pipe's vibration.
In practical engineering, the unilateral gap constraint impact vibration in fluid-conveying pipes is a critical concern, often arising from constraint loosening or the presence of barriers around the pipe. These factors can significantly affect the service life and safety reliability of the pipes. A tension and compression anisotropy spring with rapidly increasing restoring force in compression but almost zero restoring force in tension is proposed to simulate the unilateral gap constraint, model a fluid-conveying pipe with a Pfluger column. Its reliability is also verified based on the bifurcation phase diagram comparison between the small and large stiffness conditions. Subsequently, we establish a vibration mechanics analysis model for the cantilever fluid-conveying pipe under foundation excitation to assess the effects of basic excitation frequency, fluid velocity, distributed follower force, position coordinate of unilateral gap constraint, and the viscoelastic coefficient on the impact vibration stability of the fluid-conveying pipe. Our findings reveal that when the period-doubling bifurcation sequence is interrupted by Bare-grazing bifurcation, the system directly transitions into chaotic vibration or induces a new period-doubling bifurcation sequence, followed by re-entry into chaotic vibration. These results provide valuable insights into the intricate dynamics of fluid-conveying pipes under foundation excitation, offering a deeper understanding of the impact of various parameters on the pipe's vibration.
摘要：
Seismic events and wave action can induce volumetric strain ( ε v ) accumulation in saturated sandy soils, leading to damage to the ground surface and structures. A quantifiable relationship exists between the generation of ε v in sandy soils under drained conditions and the development of pore water pressures under undrained conditions. In this study, the impact of relative density ( D r ), cyclic stress path, and stress level on the characteristics of volumetric strain ( ε v ) generation in saturated coral sands (SCS) was evaluated through drained tests employing various cyclic stress paths. The test findings demonstrate that the rate of ε v accumulation in SCS is notably affected by the cyclic stress path. The rise in peak volumetric strain ( ε vp ) in SCS, as a function of the number of cycles, conforms to the arctangent function model. The unit cyclic stress ratio (USR) was employed as an indicator of complex cyclic loading levels. It was determined that coefficient ( ε vp ) u is positively correlated with USR at a specific D r . At the same D r , coefficient C N 1 exhibits a positive correlation with USR, while coefficient C N 2 displays a negative correlation with USR, following a power-law relationship. Irrespective of cyclic loading conditions, ε vp rises with an increase in generalized shear strain amplitude ( γ ga ). A power function model was established to represent the relationship between ε vp and γ ga . The coefficient ζ 1 decreases as D r increases. Comparisons were drawn between ε vp and γ ga for Ottawa sand and SCS. The results indicate that, as D r of Ottawa sand increases from 30 % to 70 %, the coefficient ζ 1 decreases from 1.54 to 0.73, representing a reduction of approximately 53 %. In contrast, under identical conditions, the coefficient ζ 1 of SCS exhibits a less pronounced decrease, from 1.16 to 0.79, corresponding to a reduction of roughly 32 %. These observations suggest that variations in D r have a more substantial impact on generating ε vp in Ottawa sand compared to SCS.
Seismic events and wave action can induce volumetric strain ( ε v ) accumulation in saturated sandy soils, leading to damage to the ground surface and structures. A quantifiable relationship exists between the generation of ε v in sandy soils under drained conditions and the development of pore water pressures under undrained conditions. In this study, the impact of relative density ( D r ), cyclic stress path, and stress level on the characteristics of volumetric strain ( ε v ) generation in saturated coral sands (SCS) was evaluated through drained tests employing various cyclic stress paths. The test findings demonstrate that the rate of ε v accumulation in SCS is notably affected by the cyclic stress path. The rise in peak volumetric strain ( ε vp ) in SCS, as a function of the number of cycles, conforms to the arctangent function model. The unit cyclic stress ratio (USR) was employed as an indicator of complex cyclic loading levels. It was determined that coefficient ( ε vp ) u is positively correlated with USR at a specific D r . At the same D r , coefficient C N 1 exhibits a positive correlation with USR, while coefficient C N 2 displays a negative correlation with USR, following a power-law relationship. Irrespective of cyclic loading conditions, ε vp rises with an increase in generalized shear strain amplitude ( γ ga ). A power function model was established to represent the relationship between ε vp and γ ga . The coefficient ζ 1 decreases as D r increases. Comparisons were drawn between ε vp and γ ga for Ottawa sand and SCS. The results indicate that, as D r of Ottawa sand increases from 30 % to 70 %, the coefficient ζ 1 decreases from 1.54 to 0.73, representing a reduction of approximately 53 %. In contrast, under identical conditions, the coefficient ζ 1 of SCS exhibits a less pronounced decrease, from 1.16 to 0.79, corresponding to a reduction of roughly 32 %. These observations suggest that variations in D r have a more substantial impact on generating ε vp in Ottawa sand compared to SCS.
作者机构：
[Chen, Shengbin; Fu, Yusong; Liu, Yingjiu; Zeng, Taotao; Deng, Qiqi] Hunan Province Key Laboratory of Pollution Control and Resources Reuse Technology, University of South China, Hengyang, 421001, Hunan, China;[Yang, Min] School of Environment and Civil Engineering, Harbin Institute of Technology (Shenzhen), Shenzheng 518055, China;[Yang, Min] Hunan Vch Environment Technology Co., Ltd, Changsha, 410014, China;[Li, Jun] College of Environment and Ecology, Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, China. Electronic address: jun.li@cqu.edu.cn
通讯机构：
[Jun Li] C;College of Environment and Ecology, Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, China
关键词：
Acidic wastewater;Biochar;U(VI) removal;ZVMn
摘要：
The chemical and radiological toxicity of uranium can present a significant risk to both human health and environmental safety. Thus, ZVMn-BC was synthesized through borohydride reduction aimed at investigating its performance in removing U(VI) in acidic environment (pH = 3). Several batch experiments were conducted to assess the sorption capability under various operational conditions and the relevant experimental data were investigated by kinetics, isotherms and thermodynamic equations. ZVMn-BC exhibited excellent resistance to interference and showed a superiority on U(VI) removal over zerovalent manganese (ZVMn) and corn straw biochar (BC). Under condition of pH 3, and ambient temperature of 303 K with 0.4 g/L of adsorbent, ZVMn-BC exhibited a theoretical sorption quantity of 274.78 mg/g. The sorption process was spontaneous and endothermic, primarily relying on chemical adsorption. The interaction mechanism involved electrostatic interaction, hydrolysis precipitation, complexation, and redox reactions. This study verified that ZVMn-BC exhibits effective performance for U(VI) eliminating in acidic wastewater.
The chemical and radiological toxicity of uranium can present a significant risk to both human health and environmental safety. Thus, ZVMn-BC was synthesized through borohydride reduction aimed at investigating its performance in removing U(VI) in acidic environment (pH = 3). Several batch experiments were conducted to assess the sorption capability under various operational conditions and the relevant experimental data were investigated by kinetics, isotherms and thermodynamic equations. ZVMn-BC exhibited excellent resistance to interference and showed a superiority on U(VI) removal over zerovalent manganese (ZVMn) and corn straw biochar (BC). Under condition of pH 3, and ambient temperature of 303 K with 0.4 g/L of adsorbent, ZVMn-BC exhibited a theoretical sorption quantity of 274.78 mg/g. The sorption process was spontaneous and endothermic, primarily relying on chemical adsorption. The interaction mechanism involved electrostatic interaction, hydrolysis precipitation, complexation, and redox reactions. This study verified that ZVMn-BC exhibits effective performance for U(VI) eliminating in acidic wastewater.
摘要：
Given the fact that retaining structures in seismically active areas are key barriers for geotechnical engineering disaster prevention and mitigation, accurately assessing their seismic stability throughout their life cycle is an extremely important and urgent task. However, the traditional stability analysis method ignores the effect of suction stress, which results in a large discrepancy between the calculated results and the engineering practice. In view of this, this study derives the work-energy balance equation that is applicable to unsaturated soils within the framework of the generalized effective stress principle, and on this basis, proposes a method for calculating the coefficient of antislip stability of unsaturated retaining walls under seismic excitations by using the energy method and incorporating the pre-existing or formation cracks into the calculation procedure. The reasonableness of the proposed method of this study was verified by comparing the calculation results with those of OptumG2 (academic version) and existing theoretical methods. Finally, a detailed parametric study was carried out to investigate the effect of main parameters on antislip stability under unsaturated steady seepage conditions.
摘要：
This study conducts the numerical implementation and solver development of four sub-models based on the Eulerian method with OpenFOAM software, which have been used in prior numerical simulations of wind-induced snow drifting. Verification studies are conducted on the sub-models to assess their applicability and limitations in the field of snow protection engineering. Wind tunnel experiments conducted on a snow fence in Hokkaido serve as a benchmark for these evaluations. A comparative analysis indicates that the mixture multiphase flow model, incorporating two-way coupling between phases, adeptly reproduces snow distribution around snow fences. In contrast, scalar transport models, which consider one-way coupling, are suitable only for studying snowdrifts in the early stage of protection engineering with relatively low snow concentrations. Efforts to integrate phase coupling effects by introducing source terms into the turbulence model are found to be unsatisfactory. By employing a mixture multiphase flow model, this study explores the effects of six typical collector fences on wind-induced snow drifting in road cuttings. Comparative analyses are performed on several aspects, including the morphology of the cutting flow field, snow distribution, snow concentration, and the protective efficacy of the fences, with the aim to evaluate the effectiveness and applicability of snow fences. The results show that collector fences exhibit effective snow protection capabilities for road cuttings. The snow fence in Hokkaido, wind fence, and the snow fence in Wyoming demonstrate the highest protection efficiency among the analyzed collector fences, indicating superior snowdrift control effectiveness within the cuttings. The protective mechanism of collector fences is to decrease the snow transport rate within the saltation layer at the entrance of the protected area, leading to a notable decrease in snow concentration within the saltation layer in the cuttings. This study offers valuable insights and suggestions for snow protection engineering in road cuttings.
This study conducts the numerical implementation and solver development of four sub-models based on the Eulerian method with OpenFOAM software, which have been used in prior numerical simulations of wind-induced snow drifting. Verification studies are conducted on the sub-models to assess their applicability and limitations in the field of snow protection engineering. Wind tunnel experiments conducted on a snow fence in Hokkaido serve as a benchmark for these evaluations. A comparative analysis indicates that the mixture multiphase flow model, incorporating two-way coupling between phases, adeptly reproduces snow distribution around snow fences. In contrast, scalar transport models, which consider one-way coupling, are suitable only for studying snowdrifts in the early stage of protection engineering with relatively low snow concentrations. Efforts to integrate phase coupling effects by introducing source terms into the turbulence model are found to be unsatisfactory. By employing a mixture multiphase flow model, this study explores the effects of six typical collector fences on wind-induced snow drifting in road cuttings. Comparative analyses are performed on several aspects, including the morphology of the cutting flow field, snow distribution, snow concentration, and the protective efficacy of the fences, with the aim to evaluate the effectiveness and applicability of snow fences. The results show that collector fences exhibit effective snow protection capabilities for road cuttings. The snow fence in Hokkaido, wind fence, and the snow fence in Wyoming demonstrate the highest protection efficiency among the analyzed collector fences, indicating superior snowdrift control effectiveness within the cuttings. The protective mechanism of collector fences is to decrease the snow transport rate within the saltation layer at the entrance of the protected area, leading to a notable decrease in snow concentration within the saltation layer in the cuttings. This study offers valuable insights and suggestions for snow protection engineering in road cuttings.
摘要：
The formation and regulation mechanisms of pore structures in porous geopolymers (PGs) remain qualitatively unclear, posing significant challenges to their practical application and performance optimization. In this study, PGs were synthesized utilizing metakaolin as the primary raw material and hydrogen peroxide as the foaming agent. Three distinct surfactants—sodium dodecyl sulfate, hydroxypropyl methylcellulose, and cetyltrimethylammonium bromide—were incorporated to fabricate three unique categories of PGs. The mechanical properties that were evaluated to quantify the surfactant effect were total porosity, pore distribution, and pore size variations using techniques such as image analysis and mercury intrusion porosimetry. This analysis highlighted the significant influence of slurry viscosity on the evolution and modification of pore structure. The results illustrate that viscosity acts as a crucial determinant influencing pore deformation, coalescence, ultimate foaming height, and connectivity within PGs. In addition, this study investigates the correlation between pore structure and the macroscopic properties of PGs. The synthesized PG samples display a broad spectrum of compressive strengths (10.03–17.89 MPa), dry densities (0.87–1.09 g/cm 3 ), and porosities (47.71%–57.41%). These findings provide valuable insights into the design and application of PGs.
The formation and regulation mechanisms of pore structures in porous geopolymers (PGs) remain qualitatively unclear, posing significant challenges to their practical application and performance optimization. In this study, PGs were synthesized utilizing metakaolin as the primary raw material and hydrogen peroxide as the foaming agent. Three distinct surfactants—sodium dodecyl sulfate, hydroxypropyl methylcellulose, and cetyltrimethylammonium bromide—were incorporated to fabricate three unique categories of PGs. The mechanical properties that were evaluated to quantify the surfactant effect were total porosity, pore distribution, and pore size variations using techniques such as image analysis and mercury intrusion porosimetry. This analysis highlighted the significant influence of slurry viscosity on the evolution and modification of pore structure. The results illustrate that viscosity acts as a crucial determinant influencing pore deformation, coalescence, ultimate foaming height, and connectivity within PGs. In addition, this study investigates the correlation between pore structure and the macroscopic properties of PGs. The synthesized PG samples display a broad spectrum of compressive strengths (10.03–17.89 MPa), dry densities (0.87–1.09 g/cm 3 ), and porosities (47.71%–57.41%). These findings provide valuable insights into the design and application of PGs.
摘要：
Microplastics (MPs) are emerging pollutants that play an important role in the spread of highly toxic heavy metals. Although the pH has been shown to exert a substantial impact on the adsorption capacity of MPs towards heavy metals, the intricate mechanisms underlying how pH functions in the adsorption of radioactive heavy metals by MPs remain largely elusive. Here, we combined batch experiments and density functional theory calculations to investigate the adsorption behavior of radioactive uranium (U) on virgin and aged (modified with –OH or –COOH groups) polystyrene (PS) MPs at pH ranging from 3.0 to 9.0. The kinetic data showed that the U adsorption capacities of virgin PS and PS–COOH MPs were in the order of pH 7.0 > pH 8.2 > pH 4.5 > pH 9.0 > pH 3.0, whereas U adsorption on PS–OH MPs displayed a trend of pH 8.2 > pH 9.0 > pH 7.0 > pH 4.5 > pH 3.0. These outcomes were confirmed by X-ray photoelectron spectroscopy and binding energy analysis. Compared to virgin PS MPs, the higher U adsorption on aged MPs might be attributed to electrostatic attraction between deprotonated –COOH and (UO 2 ) 3 (OH) 5 + at pH 7.0 for the PS–COOH MPs and between –OH and (UO 2 ) 4 (OH) 7 + or (UO 2 ) 3 (OH) 7 − at pH 8.2 for the PS–OH MPs. Intermolecular interaction calculations demonstrated that hydrogen bonding interaction driven by electrostatic and polarization energies contributed to the improved U adsorption amount of the PS–COOH MPs at pH 7.0 and the PS–OH MPs at pH 8.2. Our understanding of the mechanisms by which pH regulates U adsorption by MPs is critical for evaluating the fate and hazard of co-existing radionuclides and MPs in aquatic environments.
Microplastics (MPs) are emerging pollutants that play an important role in the spread of highly toxic heavy metals. Although the pH has been shown to exert a substantial impact on the adsorption capacity of MPs towards heavy metals, the intricate mechanisms underlying how pH functions in the adsorption of radioactive heavy metals by MPs remain largely elusive. Here, we combined batch experiments and density functional theory calculations to investigate the adsorption behavior of radioactive uranium (U) on virgin and aged (modified with –OH or –COOH groups) polystyrene (PS) MPs at pH ranging from 3.0 to 9.0. The kinetic data showed that the U adsorption capacities of virgin PS and PS–COOH MPs were in the order of pH 7.0 > pH 8.2 > pH 4.5 > pH 9.0 > pH 3.0, whereas U adsorption on PS–OH MPs displayed a trend of pH 8.2 > pH 9.0 > pH 7.0 > pH 4.5 > pH 3.0. These outcomes were confirmed by X-ray photoelectron spectroscopy and binding energy analysis. Compared to virgin PS MPs, the higher U adsorption on aged MPs might be attributed to electrostatic attraction between deprotonated –COOH and (UO 2 ) 3 (OH) 5 + at pH 7.0 for the PS–COOH MPs and between –OH and (UO 2 ) 4 (OH) 7 + or (UO 2 ) 3 (OH) 7 − at pH 8.2 for the PS–OH MPs. Intermolecular interaction calculations demonstrated that hydrogen bonding interaction driven by electrostatic and polarization energies contributed to the improved U adsorption amount of the PS–COOH MPs at pH 7.0 and the PS–OH MPs at pH 8.2. Our understanding of the mechanisms by which pH regulates U adsorption by MPs is critical for evaluating the fate and hazard of co-existing radionuclides and MPs in aquatic environments.
作者机构：
School of Civil Engineering, University of South China, Hengyang 421001, China;[Guodong Zhao] Hunan Provincial Key Laboratory of High Performance Special Concrete, Hengyang 421001, China;[Yihui Shi; Yun Zhou] Hunan Yihui Construction Co.LTD, China;Henan Zhenghong Industrial Co. LTD, China;[Fengling Ran; Qing Liu; Dan Jin] School of Civil Engineering, University of South China, Hengyang 421001, China<&wdkj&>Hunan Provincial Key Laboratory of High Performance Special Concrete, Hengyang 421001, China
通讯机构：
[Qing Liu] S;School of Civil Engineering, University of South China, Hengyang 421001, China<&wdkj&>Hunan Provincial Key Laboratory of High Performance Special Concrete, Hengyang 421001, China
摘要：
Geopolymer Mortar was prepared using Alkali-Leached Lead-Zinc Slag Powder (ALSP) and metakaolin (MK), and its properties were verified through mechanical analysis, XRD, and SEM. Results showed that the optimal conditions—an alkali activator modulus (M) of 1.0, a liquid-to-binder ratio (R ltb ) of 0.50, and an binder-to-sand ratio (R bts ) of 0.30—resulted in maximum 28-day compressive and flexural strengths of 44.49 MPa and 5.54 MPa, respectively. This is due to the formation of a complex, dense silico-aluminate gel from the reactive silico-aluminates in both ALSP and MK under these conditions, which in turn led to a compact internal structure and thus increased the strength of the geopolymer mortar.
Geopolymer Mortar was prepared using Alkali-Leached Lead-Zinc Slag Powder (ALSP) and metakaolin (MK), and its properties were verified through mechanical analysis, XRD, and SEM. Results showed that the optimal conditions—an alkali activator modulus (M) of 1.0, a liquid-to-binder ratio (R ltb ) of 0.50, and an binder-to-sand ratio (R bts ) of 0.30—resulted in maximum 28-day compressive and flexural strengths of 44.49 MPa and 5.54 MPa, respectively. This is due to the formation of a complex, dense silico-aluminate gel from the reactive silico-aluminates in both ALSP and MK under these conditions, which in turn led to a compact internal structure and thus increased the strength of the geopolymer mortar.
期刊：
Journal of Radioanalytical and Nuclear Chemistry,2025年:1-15 ISSN：0236-5731
通讯作者：
Zeng, TT
作者机构：
[Xie, Shuibo; Xiong, Zhiyu; Fu, Yusong; Zeng, TT; Zeng, Taotao; Wang, Guohua; Deng, Qiqi] Univ South China, Hunan Prov Key Lab Pollut Control & Resources Reus, Hengyang 421001, Peoples R China.;[Zhang, Mingjuan] Anhui Univ Sci & Technol, Sch Earth & Environm, Huainan 232001, Peoples R China.;[Wang, Zhi] Hunan Vch Environm Technol Co Ltd, Changsha 410014, Peoples R China.
通讯机构：
[Zeng, TT ] U;Univ South China, Hunan Prov Key Lab Pollut Control & Resources Reus, Hengyang 421001, Peoples R China.
关键词：
Wastewater;Uranium;Biochar;nFe–ZnO
摘要：
This study used kelp to create biochar (BC) and then modified it with iron-doped zinc oxide (nFe-ZnO) to prepare Fe-ZnO@BC. Under optimal conditions, the adsorption capacity of Fe-ZnO@BC for U(VI) was 146.16 mg g-1. Freundlich isotherm and quasi-second order kinetic model exhibited excellent fitting to the isotherm and kinetics of uranium adsorption by Fe-ZnO@BC, respectively. The thermodynamic analysis indicated that the U(VI) adsorption process was endothermic and spontaneous. After six adsorption cycles, Fe-ZnO@BC retained its remarkable U(VI) removal performance. Advanced characterization techniques suggested that the main mechanism involved surface adsorption and reduction. These findings imply that Fe-ZnO@BC is a viable adsorbent for wastewater cleanup involving uranium contamination.
期刊：
SEPARATION AND PURIFICATION TECHNOLOGY,2025年357:130115 ISSN：1383-5866
通讯作者：
Dong Xie
作者机构：
School of Civil Engineering, University of South China, Hengyang 421001, China;National and Local Joint Engineering Research Center of Airborne Pollutants Treatment and Radioactive Protection in Building Environment, Hengyang 421001, China;[Yang, Chen; Xie, Dong; Li, Suzhe; Song, Luyuan; Yuan, Zixuan] School of Civil Engineering, University of South China, Hengyang 421001, China<&wdkj&>National and Local Joint Engineering Research Center of Airborne Pollutants Treatment and Radioactive Protection in Building Environment, Hengyang 421001, China
通讯机构：
[Dong Xie] S;School of Civil Engineering, University of South China, Hengyang 421001, China<&wdkj&>National and Local Joint Engineering Research Center of Airborne Pollutants Treatment and Radioactive Protection in Building Environment, Hengyang 421001, China
摘要：
Polyimide (PI) nanofiber materials have garnered attention in the field of high-temperature filtration due to their exceptional thermal stability. Enhancing their filtration efficiency for fine particulate matter (PM2.5–0.3) and exploring their performance limits under high-temperature conditions are crucial for high-temperature filtration applications. In this study, a metal wire-based needle-free electrospinning technique was employed to electrospin polyimide (PI) material, successfully fabricating nanofiber membranes with an average fiber diameter of 122 nm within just 10 min at an elevated electrospinning voltage of 80 kV (electric field:333.33 kV/m). The Fine-diameter PI nanofiber membrane achieved a filtration efficiency of 99.99 % for PM0.3 and operated at a low resistance of 189.18 Pa. After continuous treatment at a high temperature of 390 °C for one hour, the Fine-diameter PI nanofiber membrane still maintained a filtration efficiency of 99.96 % for PM0.3 and was capable of completely filtering PM2.5. This demonstrates the excellent stability and reliability of the Fine-diameter PI nanofiber membrane under extreme temperature conditions. Additionally, the membrane exhibited outstanding hydrophobic properties, with a static contact angle of 130 ± 3°, aiding in maintaining its filtration performance in humid environments. The Fine-diameter PI nanofiber membrane developed in this study offers a novel fabrication strategy for PM filtration in high-temperature environments and provides new insights into its limit performance.
Polyimide (PI) nanofiber materials have garnered attention in the field of high-temperature filtration due to their exceptional thermal stability. Enhancing their filtration efficiency for fine particulate matter (PM2.5–0.3) and exploring their performance limits under high-temperature conditions are crucial for high-temperature filtration applications. In this study, a metal wire-based needle-free electrospinning technique was employed to electrospin polyimide (PI) material, successfully fabricating nanofiber membranes with an average fiber diameter of 122 nm within just 10 min at an elevated electrospinning voltage of 80 kV (electric field:333.33 kV/m). The Fine-diameter PI nanofiber membrane achieved a filtration efficiency of 99.99 % for PM0.3 and operated at a low resistance of 189.18 Pa. After continuous treatment at a high temperature of 390 °C for one hour, the Fine-diameter PI nanofiber membrane still maintained a filtration efficiency of 99.96 % for PM0.3 and was capable of completely filtering PM2.5. This demonstrates the excellent stability and reliability of the Fine-diameter PI nanofiber membrane under extreme temperature conditions. Additionally, the membrane exhibited outstanding hydrophobic properties, with a static contact angle of 130 ± 3°, aiding in maintaining its filtration performance in humid environments. The Fine-diameter PI nanofiber membrane developed in this study offers a novel fabrication strategy for PM filtration in high-temperature environments and provides new insights into its limit performance.
作者：
Yang Yang*;Jun Zeng;Boyu Yang;Junsong Hu;Ziyan Zhang
期刊：
International Journal of Refrigeration,2025年 ISSN：0140-7007
通讯作者：
Yang Yang
作者机构：
School of Civil Engineering, University of South China, Hengyang, 421001, Hunan, China;Key Lab of Hunan for the Technologies of Energy Conservation in Prefabricated Buildings, Hengyang, 421001, Hunan, China;[Yang Yang; Jun Zeng; Boyu Yang; Junsong Hu; Ziyan Zhang] School of Civil Engineering, University of South China, Hengyang, 421001, Hunan, China<&wdkj&>Key Lab of Hunan for the Technologies of Energy Conservation in Prefabricated Buildings, Hengyang, 421001, Hunan, China
通讯机构：
[Yang Yang] S;School of Civil Engineering, University of South China, Hengyang, 421001, Hunan, China<&wdkj&>Key Lab of Hunan for the Technologies of Energy Conservation in Prefabricated Buildings, Hengyang, 421001, Hunan, China
摘要：
Reducing energy consumption in buildings is a crucial component in the pursuit of carbon neutrality and sustainable social development. The air-conditioning systems account for a significant portion of a building's energy consumption and therefore require special attention to their energy efficiency. These air-conditioning systems that incorporate indirect evaporative cooling (IEC) technology are a viable energy-saving strategy. However, these hybrid systems are mainly designed for hot-dry climates, and limited research has focused on the coupling advantages of condenser pre-cooling and reheating energy recovery via IEC through different operating modes. In this paper, a novel multi-mode split evaporative-cooling hybrid air-conditioning system (MVC-IEC) is proposed, which utilizes the IEC cycle to achieve condenser pre-cooling and supply air reheating. Simultaneously, it features five operating modes to adapt to the changing ambient climatic conditions. Subsequently, the energy performance of the MVC-IEC system was primarily investigated under different operating conditions. The MVC-IEC demonstrates a more pronounced energy-saving advantage under high temperature, medium-low humidity and low reheat load conditions. In addition, the MVC-IEC has acceptable application potential in both hot-humid and hot-dry cities (Changsha, Nanjing, Zhengzhou and Xi'an). The seasonal COP for the MVC-IEC is reached by 3.9−4.6. And compared with MVC-HRC, the MVC-IEC achieves an energy-saving rate of 10.8−16.3% and reduces carbon emissions by 0.42−0.80 kg/year.
Reducing energy consumption in buildings is a crucial component in the pursuit of carbon neutrality and sustainable social development. The air-conditioning systems account for a significant portion of a building's energy consumption and therefore require special attention to their energy efficiency. These air-conditioning systems that incorporate indirect evaporative cooling (IEC) technology are a viable energy-saving strategy. However, these hybrid systems are mainly designed for hot-dry climates, and limited research has focused on the coupling advantages of condenser pre-cooling and reheating energy recovery via IEC through different operating modes. In this paper, a novel multi-mode split evaporative-cooling hybrid air-conditioning system (MVC-IEC) is proposed, which utilizes the IEC cycle to achieve condenser pre-cooling and supply air reheating. Simultaneously, it features five operating modes to adapt to the changing ambient climatic conditions. Subsequently, the energy performance of the MVC-IEC system was primarily investigated under different operating conditions. The MVC-IEC demonstrates a more pronounced energy-saving advantage under high temperature, medium-low humidity and low reheat load conditions. In addition, the MVC-IEC has acceptable application potential in both hot-humid and hot-dry cities (Changsha, Nanjing, Zhengzhou and Xi'an). The seasonal COP for the MVC-IEC is reached by 3.9−4.6. And compared with MVC-HRC, the MVC-IEC achieves an energy-saving rate of 10.8−16.3% and reduces carbon emissions by 0.42−0.80 kg/year.
期刊：
Separation and Purification Technology,2025年354:129032 ISSN：1383-5866
通讯作者：
Dong Xie
作者机构：
School of Resource Environment and Safety Engineering, University of South China, Hengyang 421001, PR China;National and Local Joint Engineering Research Center of Airborne Pollutants Treatment and Radioactive Protection in Building Environment, Hengyang 421001, PR China;School of Civil Engineering, University of South China, Hengyang 421001, PR China;[Tang, Zengming; Li, Suzhe] School of Resource Environment and Safety Engineering, University of South China, Hengyang 421001, PR China<&wdkj&>National and Local Joint Engineering Research Center of Airborne Pollutants Treatment and Radioactive Protection in Building Environment, Hengyang 421001, PR China;[Xie, Dong; Huang, Leijuan] National and Local Joint Engineering Research Center of Airborne Pollutants Treatment and Radioactive Protection in Building Environment, Hengyang 421001, PR China<&wdkj&>School of Civil Engineering, University of South China, Hengyang 421001, PR China
通讯机构：
[Dong Xie] N;National and Local Joint Engineering Research Center of Airborne Pollutants Treatment and Radioactive Protection in Building Environment, Hengyang 421001, PR China<&wdkj&>School of Civil Engineering, University of South China, Hengyang 421001, PR China
摘要：
Activated carbon fiber (ACF) is widely used as a critical adsorbent for removing gaseous radioiodine produced during spent fuel reprocessing. However, conventional ACF exhibits a broad pore distribution and high moisture affinity, significantly diminishing their effectiveness in capturing iodine under humid conditions. In this study, we endowed bare ACF with the dual functions of preferentially I 2 -matched pores (93.62 % microporosity) and hydrophobicity (water contact angle of 132.1°) using a facile method of depositing polydivinylbenzene (PDVB) nanoparticles, overcoming the limitations of traditional modification methods that have a single target. We successfully prepared amine-functionalized hydrophobic ACF (ACF-PDA@PDVB-HMTA) with a high specific surface area (1392 m 2 /g) by introducing iodine-affinity reactive groups ( NH 2 , C N, and OH). ACF-PDA@PDVB-HMTA exhibited a groundbreaking static adsorption capacity of 1886 ± 56 mg/g for I 2 at 96 % relative humidity. Notably, its dynamic iodine adsorption on iodine-water vapor mixed stream was 1873.78 mg/g, which is 66.31 % higher than that of the original ACF (1126.7 mg/g) at real-life conditions of 75 °C and 50 % relative humidity, underscoring the synergistic “1 + 1 + 1 = 3” effect of the three mechanisms. The scalable application of the spray-deposited PDVB approach to other porous carbon materials also yielded exemplary modification results. This synergistic strategy provides a promising solution for improving the overall I 2 capture.
Activated carbon fiber (ACF) is widely used as a critical adsorbent for removing gaseous radioiodine produced during spent fuel reprocessing. However, conventional ACF exhibits a broad pore distribution and high moisture affinity, significantly diminishing their effectiveness in capturing iodine under humid conditions. In this study, we endowed bare ACF with the dual functions of preferentially I 2 -matched pores (93.62 % microporosity) and hydrophobicity (water contact angle of 132.1°) using a facile method of depositing polydivinylbenzene (PDVB) nanoparticles, overcoming the limitations of traditional modification methods that have a single target. We successfully prepared amine-functionalized hydrophobic ACF (ACF-PDA@PDVB-HMTA) with a high specific surface area (1392 m 2 /g) by introducing iodine-affinity reactive groups ( NH 2 , C N, and OH). ACF-PDA@PDVB-HMTA exhibited a groundbreaking static adsorption capacity of 1886 ± 56 mg/g for I 2 at 96 % relative humidity. Notably, its dynamic iodine adsorption on iodine-water vapor mixed stream was 1873.78 mg/g, which is 66.31 % higher than that of the original ACF (1126.7 mg/g) at real-life conditions of 75 °C and 50 % relative humidity, underscoring the synergistic “1 + 1 + 1 = 3” effect of the three mechanisms. The scalable application of the spray-deposited PDVB approach to other porous carbon materials also yielded exemplary modification results. This synergistic strategy provides a promising solution for improving the overall I 2 capture.
作者机构：
[Li, X; Li, X. F.; Long, F.] Cent South Univ, Sch Civil Engn, Changsha 410075, Peoples R China.;[Hu, Z. L.; Hu, Z] Univ South China, Sch Civil Engn, Hengyang 421001, Peoples R China.
通讯机构：
[Li, X ] C;[Hu, Z ] U;Cent South Univ, Sch Civil Engn, Changsha 410075, Peoples R China.;Univ South China, Sch Civil Engn, Hengyang 421001, Peoples R China.
摘要：
This article studies a nanoscale plate assembled by two nanoplates with surface elasticity containing an interface crack when the crack surfaces are loaded by bending moment and shear force. The classical (Kirchhoff) plate theory incorporating Gurtin–Murdoch (GM) surface elasticity is utilized. A bimaterial nanoplate with an interface through-thickness crack is converted to a mixed boundary-value problem, and is solved by using the Fourier integral transform. A singular integral equation with two Cauchy kernels for either uniform bending moment or constant effective shear force is derived. The closed-form solution is given and the exact expressions for the bending moment and shear force are determined. Specially, the oscillatory singular behavior of the crack-tip field is found. When two dissimilar nanoplates are identical, the oscillatory singularity disappears but singularity dominated by r − 3 / 2 and r − 1 / 2 ( r being the distance from the crack tip) remains. Additionally, when the surface elasticity is neglected, the results of a large-scale assembled plate with a through-thickness interface crack are directly derived from the present. The obtained results show that surface elasticity has a significant effect on the energy release rate of the oscillatory crack-tip field.
This article studies a nanoscale plate assembled by two nanoplates with surface elasticity containing an interface crack when the crack surfaces are loaded by bending moment and shear force. The classical (Kirchhoff) plate theory incorporating Gurtin–Murdoch (GM) surface elasticity is utilized. A bimaterial nanoplate with an interface through-thickness crack is converted to a mixed boundary-value problem, and is solved by using the Fourier integral transform. A singular integral equation with two Cauchy kernels for either uniform bending moment or constant effective shear force is derived. The closed-form solution is given and the exact expressions for the bending moment and shear force are determined. Specially, the oscillatory singular behavior of the crack-tip field is found. When two dissimilar nanoplates are identical, the oscillatory singularity disappears but singularity dominated by r − 3 / 2 and r − 1 / 2 ( r being the distance from the crack tip) remains. Additionally, when the surface elasticity is neglected, the results of a large-scale assembled plate with a through-thickness interface crack are directly derived from the present. The obtained results show that surface elasticity has a significant effect on the energy release rate of the oscillatory crack-tip field.
作者机构：
[Liu, Qing; Li, Weifan; Yang, Jingjing] Univ South China, Sch Civil Engn, Hengyang 421001, Peoples R China.;[Liu, Qing; Yang, Jingjing] Hunan Prov Key Lab Pollut Control & Resource Utili, Hengyang 421001, Peoples R China.;[Hua, Yilong; Zhao, Guodong; Zhao, GD] Univ South China, Sch Resources Environm & Safety Engn, Hengyang 421001, Peoples R China.
通讯机构：
[Liu, Q ; Zhao, GD ] U;Univ South China, Sch Civil Engn, Hengyang 421001, Peoples R China.;Univ South China, Sch Resources Environm & Safety Engn, Hengyang 421001, Peoples R China.
关键词：
Tannic acid;Magnetite;U(VI);Metal phenolic film
摘要：
This study reports the preparation and application of Fe3O4 nanoparticles modified by tannic acid and trivalent iron for U(Ⅵ) removal. The phenolic hydroxyl group on the tannic acid molecule can be complexed with U(Ⅵ), so as to achieve the goal of adsorping uranium from wastewater, and the maximum adsorption capacity of TA-FeIII@Fe3O4 can reach 98.2 mg/g. Through the research on pH, dosage, adsorption kinetics and adsorption thermodynamics indicted that it were excepting as a new green adsorbent for removing U(Ⅵ) from wastewater.
This study reports the preparation and application of Fe3O4 nanoparticles modified by tannic acid and trivalent iron for U(Ⅵ) removal. The phenolic hydroxyl group on the tannic acid molecule can be complexed with U(Ⅵ), so as to achieve the goal of adsorping uranium from wastewater, and the maximum adsorption capacity of TA-FeIII@Fe3O4 can reach 98.2 mg/g. Through the research on pH, dosage, adsorption kinetics and adsorption thermodynamics indicted that it were excepting as a new green adsorbent for removing U(Ⅵ) from wastewater.
期刊：
Shock and Vibration,2025年2025(1):8100588- ISSN：1070-9622
通讯作者：
Hu, R
作者机构：
[Deng, Xianshi] Hunan Polytech Environm & Biol, Sch Landscape, Hengyang 421005, Peoples R China.;[Chang, Yan; Hu, Rong; Deng, Heng; Lu, Duofang; Hu, R] Pearl River Water Resources Res Inst, Dept Hydraul Engn, Guangzhou 510611, Peoples R China.;[Hu, Rong; Lu, Duofang; Hu, R] Univ South China, Sch Civil Engn, Hengyang 421001, Hunan, Peoples R China.
通讯机构：
[Hu, R ] P;Pearl River Water Resources Res Inst, Dept Hydraul Engn, Guangzhou 510611, Peoples R China.;Univ South China, Sch Civil Engn, Hengyang 421001, Hunan, Peoples R China.
关键词：
crack propagation;half-model test;impact load;nonpersistent jointed rock mass;rock dynamics
摘要：
Normal dynamic mechanical characteristics of the jointed rock mass are of great significance for studying the working state of rock mass with nonpersistent joint. In this paper, combined with the joint normal deformation theory, the rock-like materials with penetration along different normal directions were analyzed under impact tests of different weights and heights. The experimental results show that under the same impact conditions, as the joint penetration length L increases from 0 to 100 mm, the peak load and joint stiffness of the rock mass joint specimen gradually decrease during the impact process, and the normal dynamic compression displacement and the normal closure of the rock mass joint gradually increase. The energy dissipation gradually decreases at the impact heights of 500, 1000, and 1500 mm. When the impact height is 2000 mm, the energy dissipation first increases and then decreases. Under the action of cyclic impact, the crack propagation path of jointed rock mass specimens is that the cracks originate at the loading place and develop to the joint surface and then spread to the weak joint end to form 90 degrees wing cracks. The crack width, propagation scale, and damage degree gradually expand with the increase in joint penetration length L.
摘要：
To accurately predict the long-term wind-induced snowdrift on building roofs, this study developed a modified numerical model within the multistage quasi-steady simulation method. A novel method was introduced to estimate prototype blowing snow duration based on wind tunnel experimental data, and a boundary mesh adaptive technique combined with the bounded radial basis function interpolation method was implemented to track dynamic boundary changes during snow drifting. Additionally, the influence of temporal parameters, including blowing snow duration, time allocation schemes, and number of stages, was systematically analyzed through the multistage quasi-steady simulation method, with validation conducted using wind tunnel experiments. The results indicate that when Anno's time similarity parameters were used to estimate the blowing snow duration for the prototype roof, the simulation results derived from the proposed methodology closely aligned with the experimental results, outperforming the previously used empirical formulas for snow transport rates. Generally, when the blowing snow duration is fixed, increasing the number of stages enhances the simulation's approximation to the actual snow drifting process; however, an optimal number of stages exists based on convergence conditions and time allocation schemes. Altering the blowing snow duration also affects the optimal number of stages, with longer and shorter durations requiring more and fewer computational stages, respectively. Numerical simulations reveal that as snow drifting progresses, the friction velocity on the roof gradually decreases, reducing the rate of snow erosion per unit of time. Consequently, the mean snow transport rate on the building roof decreases non-linearly over time. The proposed numerical model can offer significant insights for designing snow loads in practical engineering applications.
作者：
Zhixiang Liu ( 刘志祥 );Zhixiang Yu ( 余志祥 )*;Mengyu Yao ( 姚梦玉 );Xiaoxiao Chen ( 陈肖笑 );Junsong Hu ( 胡竣淞 );...
期刊：
Physics of Fluids,2025年37(2):027155 ISSN：1070-6631
通讯作者：
Zhixiang Yu ( 余志祥 )
作者机构：
[Xiaoxiao Chen ( 陈肖笑 )] School of Civil Engineering, Suzhou University of Science and Technology , Suzhou 215000, China;[Zhixiang Liu ( 刘志祥 ); Mengyu Yao ( 姚梦玉 ); Junsong Hu ( 胡竣淞 ); Dong Xie ( 谢东 )] School of Civil Engineering, University of South China , Hengyang 421001, China
摘要：
Wind-induced snow transport plays a key role in uneven snow drift on rooftops, yet the mechanisms driving this transport remain poorly understood. To investigate the mass transport of snow drifting on rooftops, this study systematically conducted a series of wind tunnel experiments using blowing snow on low-rise flat roofs. High-density silica particles were employed, and various test parameters, including snowfall, wind speed, roof span, and blowing duration, were varied. The results showed that the snow-depth shape on the central axis of a roof can be summarized and simplified into four typical patterns according to different test conditions. The average transport rate on a flat roof decreases exponentially with the duration of blowing snow. A greater wind speed will significantly increase the transport rate on the roof. The saturated mass transport rate can be described by a polynomial of the wind speed and particle threshold wind speed under no-snowfall conditions and can be expressed as the product of snowfall intensity and saturated length for snowfall conditions. When drifting snow is not saturated, the initial transport rate on a roof can be expressed as the product of the saturated transport rate and the power function of a roof span, and the power index value is 0.65 for a no-snowfall condition and 0.75 for a snowfall condition. For saturated length, since snowfall leads to an increase in particle mass flux in the saltation layer and a decrease in particle threshold wind speed, the saturated length with snowfall will be smaller than that without snowfall and will decrease with an increase in snowfall intensity. Finally, the snow distribution pattern and blowing snow transport model derived in this study can provide valuable insights for snow load design in practical engineering applications.
