摘要：
Fatigue failure of joints is a critical factor affecting structural safety design. This study investigates the failure mechanism of aluminum (Al)-steel tubular joints fabricated via magnetic pulse crimping (MPC) using multiscale characterization techniques. Shear effects caused the thinning of the Al tube, which induced the formation of a notch on the inner surface. The mechanical interlocking of the material and the notch effect led to stress concentration, thereby promoting fatigue crack initiation (FCI) at the notch. Fracture morphology indicated that FCI was a mixture of intergranular and transgranular fracture. Interestingly, under higher stress conditions (58.5 MPa), the fatigue crack propagation (FCP) rate was extremely fast. The crack propagation process lacked a steady-state stage, with no distinct fatigue striations forming before fracture occurred. The features of the dimples were the main characteristic of final fracture (FF). Electron backscattered diffraction (EBSD) results showed that the differences in plastic deformation degree, dislocation density, and grain Schmid factor (SF) value were the main causes of intergranular and transgranular fracture in FCI.
Fatigue failure of joints is a critical factor affecting structural safety design. This study investigates the failure mechanism of aluminum (Al)-steel tubular joints fabricated via magnetic pulse crimping (MPC) using multiscale characterization techniques. Shear effects caused the thinning of the Al tube, which induced the formation of a notch on the inner surface. The mechanical interlocking of the material and the notch effect led to stress concentration, thereby promoting fatigue crack initiation (FCI) at the notch. Fracture morphology indicated that FCI was a mixture of intergranular and transgranular fracture. Interestingly, under higher stress conditions (58.5 MPa), the fatigue crack propagation (FCP) rate was extremely fast. The crack propagation process lacked a steady-state stage, with no distinct fatigue striations forming before fracture occurred. The features of the dimples were the main characteristic of final fracture (FF). Electron backscattered diffraction (EBSD) results showed that the differences in plastic deformation degree, dislocation density, and grain Schmid factor (SF) value were the main causes of intergranular and transgranular fracture in FCI.
期刊：
Frontiers in Environmental Chemistry,2025年5:1511657 ISSN：2673-4486
通讯作者：
Zhang, W
作者机构：
[Aihe Wang; Wei Zhang; Zhang, Wei; Jinkai Shu] Hunan City Univ, Sch Municipal & Mapping Engineer, Yiyang, Hunan, Peoples R China.;[Wei Zhang; Zhang, Wei; Zheng Wang] Shenyang Jianzhu Univ, Sch Municipal & Environm Engn, Shenyang, Liaoning, Peoples R China.;[Aihe Wang; Wei Zhang; Zhang, Wei; Jinkai Shu] Hunan Prov Village Drinking Water Qual Safety Engn, Yiyang, Hunan, Peoples R China.;[Hai Lin; Xuchao Yan] Yiyang City Commod Qual Supervis & Inspect Inst, Yiyang, Hunan, Peoples R China.
通讯机构：
[Zhang, W ] H;Hunan City Univ, Sch Municipal & Mapping Engineer, Yiyang, Hunan, Peoples R China.;Shenyang Jianzhu Univ, Sch Municipal & Environm Engn, Shenyang, Liaoning, Peoples R China.;Hunan Prov Village Drinking Water Qual Safety Engn, Yiyang, Hunan, Peoples R China.
摘要：
Phytic acid was investigated as an organophosphorus pollutant. Titanium dioxide (TiO2) doped with Ce and N was prepared using the sol-gel method and loaded onto a modified shell power to produce modified shell powder/Ce-N-TiO2 (Msp/CeNT). The combined effects of adsorption and photocatalysis on phytic acid were explored. The actual phytic acid degradation rate with the composite photocatalyst was higher than the sum of the adsorption removal rate of phytic acid using the modified shell powder and the photocatalytic degradation removal rate of phytic acid using the Ce-N-TiO2 photocatalyst. Msp/CeNT synergistically affected adsorption and photocatalytic degradation. The effects of different factors, such as reaction temperature, catalyst dosage, initial pH, stirring speed, and light intensity, on the combined effect were investigated. The results showed that the synergistic effect increases with the increase of light intensity. Increasing the reaction temperature, catalyst dosage, initial pH, and stirring speed first increased and then decreased the synergistic effect of the composite photocatalysts. Phytic acid (69.54%) was degraded within 4 h when the temperature, pH, catalyst dosage, stirring speed, and light intensity were 25 degrees C, 5, 1 g/L, 300 rpm, and 500 W, respectively. We investigated and prepared a composite photocatalytic material, developing a new theoretical method for degrading organophosphorus dissolved in water and providing a basis for treating lake eutrophication as a practical application.
关键词：
All-light shale ceramsite concrete;Rebar;Bond strength;Bond-slip behavior;Bond-slip predictive model
摘要：
Driven by the growing demand for lightweight materials in sustainable construction, the interfacial bonding mechanism between all-lightweight shale ceramsite concrete and rebar requires further investigation. Therefore, 57 central pullout tests were conducted to systematically evaluate the effects of concrete strength, rebar diameter, surface shapes, and yield strength on the bond behavior. The results revealed two failure modes, pullout and splitting failures, controlled by the ratio of concrete cover thickness to strength. Increased concrete strength significantly enhanced bond capacity, with ribbed rebars exhibiting 2.4 to 4.6 times higher bond strength than plain rebars, while yield strength exerted negligible influence. Rebar diameter exhibited contrasting effects, with larger diameters improving bond performance under pullout failure while smaller diameters performed better under splitting failure. The ascending branches of bond-slip curves exhibited decelerated growth rates with increased rebar diameter or concrete strength. Post-peak behavior diverged sharply with splitting failures causing abrupt stress reductions, while pullout failures exhibited gradual degradation due to concrete crushing and reduced mechanical interlock. Based on diffuse crack theory and thick-walled cylinder theory, the theoretical models for bond strength, peak slip and bond-slip relationships were developed, achieving a maximum prediction error of 16.22% and mean squared error of 1.48 for peak slip. The proposed models demonstrated superior accuracy with 80% experimental data alignment, outperforming existing prediction frameworks.
Driven by the growing demand for lightweight materials in sustainable construction, the interfacial bonding mechanism between all-lightweight shale ceramsite concrete and rebar requires further investigation. Therefore, 57 central pullout tests were conducted to systematically evaluate the effects of concrete strength, rebar diameter, surface shapes, and yield strength on the bond behavior. The results revealed two failure modes, pullout and splitting failures, controlled by the ratio of concrete cover thickness to strength. Increased concrete strength significantly enhanced bond capacity, with ribbed rebars exhibiting 2.4 to 4.6 times higher bond strength than plain rebars, while yield strength exerted negligible influence. Rebar diameter exhibited contrasting effects, with larger diameters improving bond performance under pullout failure while smaller diameters performed better under splitting failure. The ascending branches of bond-slip curves exhibited decelerated growth rates with increased rebar diameter or concrete strength. Post-peak behavior diverged sharply with splitting failures causing abrupt stress reductions, while pullout failures exhibited gradual degradation due to concrete crushing and reduced mechanical interlock. Based on diffuse crack theory and thick-walled cylinder theory, the theoretical models for bond strength, peak slip and bond-slip relationships were developed, achieving a maximum prediction error of 16.22% and mean squared error of 1.48 for peak slip. The proposed models demonstrated superior accuracy with 80% experimental data alignment, outperforming existing prediction frameworks.
作者机构：
[Cheng, Xiaokang; Xiao, Junyi; Peng, Jianxin; Zhang, Jianren] Changsha Univ Sci & Technol, Sch Civil Engn, Key Lab Bridge Engn Safety Control, Dept Educ, Changsha 410114, Hunan, Peoples R China.;[Xiao, Junyi] Guangzhou Vocat Coll Technol & Business, Sch Emergency Technol, Guangzhou 511442, Guangdong, Peoples R China.;[Yang, Yiming] Hunan City Univ, Sch Civil Engn, Yiyang 413000, Hunan, Peoples R China.;[Dong, You] Hong Kong Polytech Univ, Dept Civil & Environm Engn, Hong Kong 999077, Peoples R China.
通讯机构：
[Peng, JX ] C;[Yang, YM ] H;Changsha Univ Sci & Technol, Sch Civil Engn, Key Lab Bridge Engn Safety Control, Dept Educ, Changsha 410114, Hunan, Peoples R China.;Hunan City Univ, Sch Civil Engn, Yiyang 413000, Hunan, Peoples R China.
关键词：
Post-tensioned concrete structures;Chloride wet-dry environment;Performance degradation;Concrete creep;Prestress loss
摘要：
The shrinkage, creep of concrete, and relaxation of prestressing tendons lead to prestress loss in prestressed concrete (PC) structures under conventional environments. The prestress loss of PC structures is also affected by corrosive environments resulting from alternating wet and dry. Therefore, a new model for predicting prestress loss under alternating damp and dry chloride environments is proposed. The model considers the coupled effects of corrosion on concrete creep and the remaining cross-sectional area of steel reinforcement/prestressing tendons. A 300-day experimental study is conducted on a series of post-tensioned prestressed concrete beams subjected to a cyclic wet-dry corrosive environment to discuss prestress loss. The effectiveness of the model is verified through experimental results. The results indicate that the existing codes underestimate the long-term prestress loss of PC structures in corrosive environments. The proposed model can accurately predict the long-term prestress loss of PC beams. Compared with conventional environments, the creep coefficient of concrete under a dry-wet alternating corrosive environment increases by 15 %, resulting in a 12.4 % increase in the long-term prestress loss of the structure.
The shrinkage, creep of concrete, and relaxation of prestressing tendons lead to prestress loss in prestressed concrete (PC) structures under conventional environments. The prestress loss of PC structures is also affected by corrosive environments resulting from alternating wet and dry. Therefore, a new model for predicting prestress loss under alternating damp and dry chloride environments is proposed. The model considers the coupled effects of corrosion on concrete creep and the remaining cross-sectional area of steel reinforcement/prestressing tendons. A 300-day experimental study is conducted on a series of post-tensioned prestressed concrete beams subjected to a cyclic wet-dry corrosive environment to discuss prestress loss. The effectiveness of the model is verified through experimental results. The results indicate that the existing codes underestimate the long-term prestress loss of PC structures in corrosive environments. The proposed model can accurately predict the long-term prestress loss of PC beams. Compared with conventional environments, the creep coefficient of concrete under a dry-wet alternating corrosive environment increases by 15 %, resulting in a 12.4 % increase in the long-term prestress loss of the structure.
期刊：
Desalination and Water Treatment,2025年322:101161 ISSN：1944-3994
通讯作者：
Li, ZP
作者机构：
[Yin, Quan; Zhou, Yi; Li, Zhiping] Hunan City Univ, Sch Civil Engn, Yiyang 413000, Peoples R China.;[Yin, Quan; Zhou, Yi; Li, Zhiping] Hunan City Univ, Hunan Engn Res Ctr Struct Safety & Disaster Preven, Yiyang 413000, Peoples R China.;[Ma, Lidong] Sinohydro Engn Bur 8 Co Ltd, Changsha 410004, Hunan, Peoples R China.
通讯机构：
[Li, ZP ] H;Hunan City Univ, Sch Civil Engn, Yiyang 413000, Peoples R China.
关键词：
Magnetic amino-functionalized biochar;Hexavalent chromium;Removal performance;Potential mechanisms
摘要：
Magnetic amino-functionalized sludge biochar (Fe@NBC) was prepared via a one-step method for efficient Cr(VI) removal from tailing wastewater. Static adsorption research was conducted to investigate the impacts of solution pH, coexisting ion, reaction times, pollutant concentrations, and reaction temperature on removing Cr(VI) from tailing wastewater. Spectroscopic analysis was used to research the removal mechanisms of Cr(VI). Compared with the original sludge biochar, Fe@NBC exhibited a more developed pore structure and richer reactive sites. Adsorption experiments showed that Fe@NBC achieved higher adsorption and reduction rates of Cr(VI) than BC, with faster reaction equilibrium time. The efficiencies of removing Cr(VI) on Fe@NBC decreased with increasing solution pH. The efficiencies of removing Cr(VI) by Fe@NBC decreased with increasing SO 4 2- concentration, while Cl - and NO - 3 held almost no impact on removing Cr(VI). The process of removing Cr(VI) by Fe@NBC followed pseudo-second-order kinetic model and Langmuir model. Thermodynamics suggested that Cr(VI) removal on Fe@NBC was a spontaneous and endothermic processes. The main mechanisms for Cr(VI) removal by Fe@NBC were coordination and reduction, while pore filling and electrostatic interactions played secondary roles. This work demonstrated that Fe@NBC, a magnetic amino-functionalized sludge biochar, was a highly efficient and environmentally friendly material for removing Cr(VI) from tailing wastewater.
Magnetic amino-functionalized sludge biochar (Fe@NBC) was prepared via a one-step method for efficient Cr(VI) removal from tailing wastewater. Static adsorption research was conducted to investigate the impacts of solution pH, coexisting ion, reaction times, pollutant concentrations, and reaction temperature on removing Cr(VI) from tailing wastewater. Spectroscopic analysis was used to research the removal mechanisms of Cr(VI). Compared with the original sludge biochar, Fe@NBC exhibited a more developed pore structure and richer reactive sites. Adsorption experiments showed that Fe@NBC achieved higher adsorption and reduction rates of Cr(VI) than BC, with faster reaction equilibrium time. The efficiencies of removing Cr(VI) on Fe@NBC decreased with increasing solution pH. The efficiencies of removing Cr(VI) by Fe@NBC decreased with increasing SO 4 2- concentration, while Cl - and NO - 3 held almost no impact on removing Cr(VI). The process of removing Cr(VI) by Fe@NBC followed pseudo-second-order kinetic model and Langmuir model. Thermodynamics suggested that Cr(VI) removal on Fe@NBC was a spontaneous and endothermic processes. The main mechanisms for Cr(VI) removal by Fe@NBC were coordination and reduction, while pore filling and electrostatic interactions played secondary roles. This work demonstrated that Fe@NBC, a magnetic amino-functionalized sludge biochar, was a highly efficient and environmentally friendly material for removing Cr(VI) from tailing wastewater.
摘要：
During shield tunnel construction, karst development along the tunnel axis and in the surrounding area frequently poses a significant threat to engineering safety. To address this challenge, this study proposes multiple grouting systems and systematically analyzes the key mechanical properties of five grout formulations through orthogonal experiments, identifying the optimal formulations for engineering applications. A predictive model was established using linear regression, and its accuracy was validated through independent single-factor experiments. The results indicate the following: (1) Water content is the primary factor influencing fluidity, with its significance varying by system composition. The lake mud-cement grout exhibits the highest compressive pstrength. Moderate sand addition enhances strength, but excessive amounts significantly reduce fluidity. Additives demonstrate system dependency: HY-4 effectively improves fluidity, while sodium silicate significantly increases strength but reduces fluidity. (2) The developed model demonstrates good goodness of fit, with coefficients of determination (R(2)) ranging from 0.74 to 0.95, without significant autocorrelation or multicollinearity. Validation experiments confirm the model's high predictive accuracy, with overall trends consistent with the measured data. (3) The lake mud-cement grout (A3B1C3) is recommended for reinforcement projects prioritizing stability, achieving a 28-day compressive strength of 4.74 MPa. The on-site wet clay-cement grout (A2B3C1) is suitable for high-permeability formations, with a strength of 1.1 MPa and a fluidity of 292.5 mm, both exceeding standard requirements. The findings provide optimized formulations and theoretical references for grouting reinforcement in karst tunnel projects.
关键词：
A. graminifolia;Acetylcholinesterase;Ephemeranthoquinone;Structure-activity
摘要：
Twelve stilbenes were isolated and characterized from Arundina graminifolia (D. Don) Hochr ( A. graminifolia. ), including arundin (1) , isoarundinin II (2) , batatasin III (3) , blestriarene A (4) , densiflorol B (5) , shancidin (6) , coeloin (7) , ephemeranthoquinone (8) , isoshancidin (9) , lusianthridin (10) , orchinol (11) , and arundinan (12) . Notably, compounds 1 and 2 are reported here for the first time from this species, thereby expanding the chemical profile of A. graminifolia . Among these, compounds 4, 7 , and 8 exhibited significant acetylcholinesterase (AChE) inhibitory activity, with IC 50 values ranging from 0.116 to 0.402 mM. Kinetic assays revealed a mixed-type inhibition mechanism for these compounds, with inhibition constants (K i ) against free AChE ranging from 0.193 to 0.542 mM, and K i ’ values for enzyme-substrate complexes between 0.157 and 0.387 mM. Structure-activity relationship analysis indicated that bibenzyl compounds did not significantly affect AChE activity, while phenanthrenes exhibited more pronounced effects. Molecular dynamics simulations suggested that compound 8 interacts with the AChE binding pocket through conformational changes, stabilizing the structure via hydrogen bonds and π-stacking interactions with key residues, including Asn84, Thr154, His480, Tyr370, and Trp83. Molecular docking studies confirmed that these stilbenes effectively inhibit AChE activity, with predicted IC 50 values closely aligning with experimental data. These findings highlight the potent AChE inhibitory effects of the active stilbene compounds from A. graminifolia , providing valuable insights into their potential as therapeutic agents for Alzheimer's disease.
Twelve stilbenes were isolated and characterized from Arundina graminifolia (D. Don) Hochr ( A. graminifolia. ), including arundin (1) , isoarundinin II (2) , batatasin III (3) , blestriarene A (4) , densiflorol B (5) , shancidin (6) , coeloin (7) , ephemeranthoquinone (8) , isoshancidin (9) , lusianthridin (10) , orchinol (11) , and arundinan (12) . Notably, compounds 1 and 2 are reported here for the first time from this species, thereby expanding the chemical profile of A. graminifolia . Among these, compounds 4, 7 , and 8 exhibited significant acetylcholinesterase (AChE) inhibitory activity, with IC 50 values ranging from 0.116 to 0.402 mM. Kinetic assays revealed a mixed-type inhibition mechanism for these compounds, with inhibition constants (K i ) against free AChE ranging from 0.193 to 0.542 mM, and K i ’ values for enzyme-substrate complexes between 0.157 and 0.387 mM.
Structure-activity relationship analysis indicated that bibenzyl compounds did not significantly affect AChE activity, while phenanthrenes exhibited more pronounced effects. Molecular dynamics simulations suggested that compound 8 interacts with the AChE binding pocket through conformational changes, stabilizing the structure via hydrogen bonds and π-stacking interactions with key residues, including Asn84, Thr154, His480, Tyr370, and Trp83. Molecular docking studies confirmed that these stilbenes effectively inhibit AChE activity, with predicted IC 50 values closely aligning with experimental data. These findings highlight the potent AChE inhibitory effects of the active stilbene compounds from A. graminifolia , providing valuable insights into their potential as therapeutic agents for Alzheimer's disease.
关键词：
Wind loading;wind turbine structure;extended foundation;transient response;response frequency
摘要：
To study the transient response characteristics of wind turbine structures–extended foundations under wind loads in mountainous areas, this paper develops a simplified analytical model based on soil–structure interaction theory. It explores the effects of constraint conditions, wind speed, and foundation shear wave speed on the transient response behavior. By analyzing the time–domain and frequency–domain trends of tower top displacement, foundation horizontal displacement, and foundation rotation angle, the relationship between foundation shear wave speed and the safe wind speed of the wind turbine is clarified. The results indicate that different constraint conditions lead to variations in the calculated resonance frequency, maximum tower top displacement, and acceleration response spectrum. Furthermore, based on the analysis of the tower top acceleration response curve, the influence interval of frequency can be categorized into three distinct ranges: stable range, small influence range, and large influence range. Wind speed primarily influences the vibration amplitudes of the three displacement components, while the overall trend of the time-displacement waveform remains unchanged. The foundation shear wave speed primarily affects the displacement of the foundation itself, exerting a smaller influence on the displacements of the wind turbine structure. Notably, the total displacement at the tower top decreases as the shear wave speed increases. Moreover, the safe wind speed of the wind turbine shows a positive correlation with the foundation shear wave speed, indicating a linear relationship between the two variables.
作者机构：
[Li, Wanting; Yang, Jingyu; Peng, Li; Yang, Tongguang] Hunan City Univ, Key Lab Smart City Energy Sensing & Edge Comp Huna, Yiyang 413000, Peoples R China.
通讯机构：
[Li, WT ] H;Hunan City Univ, Key Lab Smart City Energy Sensing & Edge Comp Huna, Yiyang 413000, Peoples R China.
关键词：
Meteorology;Wind power generation;Predictive models;Accuracy;Wind turbines;Wind forecasting;Wind speed;Rain;Fluctuations;Atmospheric modeling;Deep learning;extreme weather;Kernel density estimation;time GAN;wind power prediction
摘要：
The prediction of wind power generation is an important basis for the rational scheduling of new energy sources in wind power. However, the severe fluctuations in wind power output under extreme weather conditions pose a serious challenge for ultra-short-term wind power output prediction. A combination forecasting method for ultra-short-term wind power that comprehensively considers extreme weather and normal weather is proposed to address the above issues. To explore the differences in power time series characteristics under different scenarios in terms of the relationships between wind power output prediction errors and different weather types, time series generative adversarial networks are used to expand small sample datasets under extreme weather conditions, and a bidirectional long short-term memory (BiLSTM) deterministic prediction model based on a time attention mechanism is established. On this basis, a kernel density estimation probability prediction model is proposed for different extreme scenarios. A case study was conducted to verify the data of a wind farm in China. At the 90% confidence level, the proposed method improved the PICP and PINAW of various extreme weather conditions by averages of 10.04% and 20.47%, respectively. The results showed that the proposed method has good adaptability for wind power prediction under extreme weather conditions.
作者机构：
[Cao, Guohui"] Hunan Engineering Research Center of Development and Application of Ceramsite Concrete Technology, Hunan City University, Yiyang 413000, China;School of Civil Engineering, University of South China, Hengyang 421200, China;Author to whom correspondence should be addressed.;["Zhang, Zaihua] Hunan Engineering Research Center of Development and Application of Ceramsite Concrete Technology, Hunan City University, Yiyang 413000, China<&wdkj&>School of Civil Engineering, University of South China, Hengyang 421200, China;[Xiao, Yuqing] Hunan Engineering Research Center of Development and Application of Ceramsite Concrete Technology, Hunan City University, Yiyang 413000, China<&wdkj&>School of Civil Engineering, University of South China, Hengyang 421200, China<&wdkj&>Author to whom correspondence should be addressed.
通讯机构：
[Yuqing Xiao] H;Hunan Engineering Research Center of Development and Application of Ceramsite Concrete Technology, Hunan City University, Yiyang 413000, China<&wdkj&>School of Civil Engineering, University of South China, Hengyang 421200, China<&wdkj&>Author to whom correspondence should be addressed.
摘要：
This study investigates the shear behavior of steel truss ceramsite concrete composite interfaces through double-sided direct shear tests and finite element simulations. The results reveal three distinct shear response phases: elastic deformation, plastic softening, and full yielding. The interfacial shear capacity arises from synergistic contributions of bond strength, friction, and truss reinforcement action. Comparative analysis of design codes identifies Eurocode 2 as providing an optimal alignment with the experimental data. An ABAQUS-based finite element model incorporating a cohesive spring composite interface mechanism confirms the model’s reliability. The findings validate Eurocode 2 for ceramsite concrete interface design and propose single-row truss configurations as economically efficient solutions for lightweight high-strength composite structures. The research results are aimed at providing a theoretical basis for the design optimization and code revision of ceramsite concrete composite structures, and promoting the wide application of lightweight high-strength concrete in sustainable buildings.
摘要：
Effective detection of bus passengers enhances the intelligence and automation of public transportation systems, but it is challenged by complex backgrounds and severe scale imbalances. To address these challenges, we introduce DAEAR-DETR, a novel neural network architecture employing Dual-Attention mechanisms and Echo Accumulative Residuals (EAR) for bus passenger detection. This model features a Dual-Attention Encoder comprising the Low-Level Local Attention Module (LLLAM) and the High-Level Global Attention Module (HLGAM). Additionally, it integrates a Bidirectional Cross-scale Feature-Fusion Module (BCFM) and a decoder. The Echo Accumulative Residual (EAR) combats information degradation by reintroducing initial input sequences throughout the Transformer encoder layers. A Gating Mechanism (GM) within the EAR connections selectively filters and enhances relevant features based on the ongoing feature process. Experimental results demonstrate the effectiveness of our approach. On the custom bus passenger dataset, DAEAR-DETR achieves 71.9% AP(50), 73.5% AR(L), and 61.6% AR(50:95), outperforming Faster R-CNN, YOLOv9, and other DETR-based methods. Furthermore, DAEAR-DETR demonstrates strong generalization on the public Caltech Pedestrian dataset, achieving Log Average Miss Rate (LAMR) of 4.16% for the Reasonable subset, 4.97% for the Small subset, and 27.79% for the Heavy Occlusion subset. A real-world bus passenger dataset is also created with 15,656 images and 76,006 labeled passengers.
摘要：
Spinel oxide has attracted interest in wastewater treatment, owing to its visible light (VIS) adsorption properties and bimetallic synergism. However, owing to the inefficient separation of photogenerated carriers and poor redox property, there is an urgent need to develop appropriate modification strategies to address these bottlenecks. This study aimed to develop CuFe 2 O 4 /CuFeSx (CFO/CFSx) heterojunction with oxygen vacancies (OVs) via an in-situ structural modification to trigger the generation of more radicals with low oxidant consumption for the efficient degradation of refractory organics. This customized heterojunction improved the light-trapping ability and photoelectrons utilisation, promoting the reduction of metal valence by photoelectrons to enhance the activation of peroxymonosulfate (PMS). Meanwhile, OVs also provided more active sites to activate PMS to generate superoxide radicals (O 2 − ), which were further converted to hydroxyl radicals ( OH) to ensure considerable oxidation capability. Notably, Sulfur-mediated metal valence reduction boosted the cycle of Cu(I)/Cu(II) and Fe(II)/Fe(III), guaranteeing the regeneration of the active sites. Triple optimisation of the modified spinel oxide presented a striking oxidant utilisation efficiency with a substantial increase in the concentration of radicals. This study provides a simple and reliable reference for designing high-performance CuFe 2 O 4 (CFO) photocatalysts for environmental remediation.
Spinel oxide has attracted interest in wastewater treatment, owing to its visible light (VIS) adsorption properties and bimetallic synergism. However, owing to the inefficient separation of photogenerated carriers and poor redox property, there is an urgent need to develop appropriate modification strategies to address these bottlenecks. This study aimed to develop CuFe 2 O 4 /CuFeSx (CFO/CFSx) heterojunction with oxygen vacancies (OVs) via an in-situ structural modification to trigger the generation of more radicals with low oxidant consumption for the efficient degradation of refractory organics. This customized heterojunction improved the light-trapping ability and photoelectrons utilisation, promoting the reduction of metal valence by photoelectrons to enhance the activation of peroxymonosulfate (PMS). Meanwhile, OVs also provided more active sites to activate PMS to generate superoxide radicals (O 2 − ), which were further converted to hydroxyl radicals ( OH) to ensure considerable oxidation capability. Notably, Sulfur-mediated metal valence reduction boosted the cycle of Cu(I)/Cu(II) and Fe(II)/Fe(III), guaranteeing the regeneration of the active sites. Triple optimisation of the modified spinel oxide presented a striking oxidant utilisation efficiency with a substantial increase in the concentration of radicals. This study provides a simple and reliable reference for designing high-performance CuFe 2 O 4 (CFO) photocatalysts for environmental remediation.
摘要：
A series of experiments were carried out to explore the impact of waste glass on the durability of concrete. In this study, waste glass was incrementally incorporated to replace sand as the fine aggregate in creating 240 concrete specimens, with substitution rates of 0%, 10%, 30%, and 50%. The concrete specimens were subjected to early strength testing on the 3rd and 7th day, followed by evaluation of strength and permeability after curing for 28 days with dry-wet cycles. Furthermore, ultrasonic wave analysis was conducted on the waveform, and the concrete’s internal phases and chemical composition were characterized by scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM-EDS). The results led to the following observations: (1) The inclusion of glass sand lowered the early compressive strength of concrete, with the lowest drop being 24.78%. However, when it was cured for 28 days and the content of glass sand was not more than 30%, the change rate of its compressive strength was between −2.85% and 3.19%, so it was practically negligible. (2) Glass sand substitution rates ranging from 10% to 30% greatly enhanced the strength of concrete under dry-wet cycles, and the 50% substitution rate significantly improved the permeability properties, although it adversely affected the strength.
作者机构：
[Li, Ni; Qin, Hua; Deng, Yaqi; Yang, Gelan; Qin, H; Chen, Hao] Hunan City Univ, Coll Informat & Elect Engn, Yiyang 413000, Hunan, Peoples R China.;[Peng, Yang] Univ Washington Bothell, Div Comp & Software Syst, Bothell, WA 98011 USA.
通讯机构：
[Qin, H ] H;Hunan City Univ, Coll Informat & Elect Engn, Yiyang 413000, Hunan, Peoples R China.
关键词：
IoT;Scheduling;Energy;Delay;Network systems
摘要：
With the fast expansion of the Internet of Things (IoT), a vast number of IoT gateways are being deployed and continuously disseminating data to proximate devices. As one of the most prevalent wireless technologies in our daily work and life, WiFi has been extensively used for data dissemination because of the widespread availability of WiFi infrastructures. However, data transmission over high-power WiFi can quickly deplete the batteries of IoT devices. Despite the introduction of numerous power saving protocols in WiFi-based IoT computer network systems, achieving both high energy efficiency and low delay remains a challenge due to the unpredictability of data traffic. To address this, we propose a dual-radio Dual-constraint Node Activation (DNA) scheduling scheme, which leverages an auxiliary low-power ZigBee radio to reactively activate the high-power WiFi radio for energy-efficient data dissemination. Besides the delay constraint required by WiFi upper-layer applications, the dual-radio energy optimization problem studied in this work is also limited by the constrained ZigBee bandwidth for performing radio activation. By jointly scheduling dual-radio duty cycles, DNA dynamically allocates ZigBee bandwidth to balance energy and delay for optimized system performance. Extensive real-world testing was conducted on a prototype dual-radio system equipped with off-the-shelf ZigBee and WiFi radios. Under medium bandwidth and delay constraints, DNA achieves an energy consumption of 7.95 mJ per data packet, which is 95.4% and 36.2% lower than the WiFi’s standard power saving protocol and a contemporary dual-radio scheduling scheme, respectively. Additionally, DNA has demonstrated superior reliability and adaptability in various scenarios.
With the fast expansion of the Internet of Things (IoT), a vast number of IoT gateways are being deployed and continuously disseminating data to proximate devices. As one of the most prevalent wireless technologies in our daily work and life, WiFi has been extensively used for data dissemination because of the widespread availability of WiFi infrastructures. However, data transmission over high-power WiFi can quickly deplete the batteries of IoT devices. Despite the introduction of numerous power saving protocols in WiFi-based IoT computer network systems, achieving both high energy efficiency and low delay remains a challenge due to the unpredictability of data traffic. To address this, we propose a dual-radio Dual-constraint Node Activation (DNA) scheduling scheme, which leverages an auxiliary low-power ZigBee radio to reactively activate the high-power WiFi radio for energy-efficient data dissemination. Besides the delay constraint required by WiFi upper-layer applications, the dual-radio energy optimization problem studied in this work is also limited by the constrained ZigBee bandwidth for performing radio activation. By jointly scheduling dual-radio duty cycles, DNA dynamically allocates ZigBee bandwidth to balance energy and delay for optimized system performance. Extensive real-world testing was conducted on a prototype dual-radio system equipped with off-the-shelf ZigBee and WiFi radios. Under medium bandwidth and delay constraints, DNA achieves an energy consumption of 7.95 mJ per data packet, which is 95.4% and 36.2% lower than the WiFi’s standard power saving protocol and a contemporary dual-radio scheduling scheme, respectively. Additionally, DNA has demonstrated superior reliability and adaptability in various scenarios.
作者机构：
[Zulv Huang; Hongxing Chen; Yan, Bo; Tao Chen; Zhangwei Yang; Lijuan Zhang; Wanqing Zeng; Xipeng Wei; Bo Yan; Lingtian Xie] South China Normal Univ, SCNU Environm Res Inst, Guangdong Engn Technol Res Ctr Source Control Comb, Guangdong Prov Key Lab Chem Pollut & Environm Safe, Guangzhou 510006, Peoples R China.;[Zulv Huang; Hongxing Chen; Yan, Bo; Tao Chen; Zhangwei Yang; Lijuan Zhang; Wanqing Zeng; Xipeng Wei; Bo Yan; Lingtian Xie] South China Normal Univ, MOE Key Lab Theoret Chem Environm, Guangzhou 510006, Peoples R China.;[Zulv Huang; Yi Huang] Hunan City Univ, Sch Mat & Chem Engn, Yiyang 413000, Peoples R China.;[Zulv Huang; Yi Huang] Key Lab Low Carbon & Environm Funct Mat Coll Hunan, Yiyang 413000, Peoples R China.;[Hongxing Chen; Yan, Bo; Tao Chen; Zhangwei Yang; Lijuan Zhang; Wanqing Zeng; Xipeng Wei; Bo Yan; Lingtian Xie] South China Normal Univ, Sch Environm, Guangzhou 510006, Peoples R China.
通讯机构：
[Yan, B ] S;South China Normal Univ, SCNU Environm Res Inst, Guangdong Engn Technol Res Ctr Source Control Comb, Guangdong Prov Key Lab Chem Pollut & Environm Safe, Guangzhou 510006, Peoples R China.;South China Normal Univ, MOE Key Lab Theoret Chem Environm, Guangzhou 510006, Peoples R China.;South China Normal Univ, Sch Environm, Guangzhou 510006, Peoples R China.
关键词：
Bacillus megaterium R01;reduction of V(V);S 0 -reducing bacteria;sulfydryl;low-molecular-weight thiols
摘要：
Microbial reduction of pentavalent vanadium [V(V)] to less toxic tetravalent vanadium [V(IV)] is associated with the biogeochemical cycling of sulfur. However, the capability of elemental sulfur-reducing bacteria ((SRB)-R-0) to reduce V(V) in the presence of elemental sulfur (S-0) remains largely unexplored. Herein, we systematically investigated the V(V) reduction capabilities and underlying mechanisms of Bacillus megaterium R01, a (SRB)-R-0 strain isolated from the stone coal mining region. Under sulfur-depleted conditions, B. megaterium R01 demonstrated limited reduction capacity (<54.3% removal efficiency for 200 mg/L V(V)). In contrast, S-0 supplementation enabled near-complete V(V) reduction (97.6 +/- 2.1%) even at elevated concentrations (400 mg/L), achieving a relatively low carbon consumption rate (TOC/V(V) of similar to 0.6). Sulfhydryl (SH) compounds, reaching 424.2 +/- 9.9 mu mol/L within 5 days, were likely crucial for reducing V(V) to V(IV). This mechanism differs from that of other V-reducing bacteria. The transcriptome analysis revealed that the up-regulation of genes associated with sulfur metabolism, cysteine, and methionine metabolism in B. megaterium R01 is likely to contribute to its enhanced resistance toward V(V). Additionally, the biosynthesis of intracellular BSH in B. megaterium R01, and the extracellular SH groups (e.g., Trx and TrxR encode enzymes) play an irreplaceable role in reducing V(V) by B. megaterium R01. This study enhances our understanding of V(V) reduction in sulfur-rich environments and suggests a promising approach for remediating V(V)-contaminated groundwater, sediments, and soils.
