The pure g-C3N4 miniature sphere (MCU) photocatalyst was synthesized via thermal polymerization of dicyandiamide, melamine, urea, and cyanuric acid. Without the addition of any sacrificial agent, MCU efficiently established a self-sustained photo-H2O2 system under visible light. Unlike many composite photocatalysts, the pure g-C3N4 system developed in this study achieves high photocatalytic performance without relying on heterojunction construction, thereby avoiding potential interface instability, simplifying synthesis, and ensuring long-term operational stability. As a result, MCU achieved a high H2O2 production rate of 653.4 mu M & sdot; h- 1 & sdot; g- 1 and realized 99.9 % degradation of Rhodamine B (RhB) within 10 min. In this system, the in situ generated H2O2 was directly activated by photogenerated electrons to produce & sdot;OH radicals, which played a crucial role in pollutant removal. The outstanding performance of MCU is attributed to its superior photoelectrochemical properties, high material stability, and the effective integration of H2O2 generation with in situ activation, offering a promising strategy for pollutant elimination without sacrificial reagents. This work provides both theoretical insights and practical guidance for the rational design of efficient, stable, and green photo-H2O2 systems.

Asphalt binder is a critical component of asphalt pavement, and fatigue damage is a primary failure mode. Characterizing its fatigue performance is important for evaluating asphalt pavement performance and design. This study investigates fatigue damage accumulation of 70# asphalt binder under different strain levels and temperatures using time sweep tests. At 20 degrees C, increasing strain from 1.5% to 3.5% reduces fatigue life from 17,380 to 2020 cycles, an 88.4% reduction. Asphalt undergoes a hardening stage under the action of LVE load. When asphalt is subjected to NLVE fatigue load, plastic flow changes its viscoelastic properties without a hardening stage. Fatigue damage accelerates, and fatigue life decreases with increasing load level and decreasing temperature. A damage accumulation model considering dissipated energy history and a temperature-dependent fatigue life prediction model () are established based on fatigue test data. Among them, c increasing from 3.72 & times; 1011 at 10 degrees C to 2.67 & times; 1012 at 20 degrees C.

Fatigue cracking is the main disease of asphalt pavement caused by repeated traffic loads. Asphalt binders are the main component of asphalt pavement, and their fatigue performance is closely related to asphalt pavement. At present, the fatigue cracking mechanism of asphalt binder is unclear, and more is based on theoretical calculation methods to characterize the crack propagation during the testing process. Therefore, this paper is based on the dynamic shear rheometer (DSR) to study the crack length in asphalt binders under different load levels and test temperatures and to quantify the cohesive delamination caused by fatigue in asphalt binders using crack length. The fracture morphology of the specimens after the experiment was evaluated using the image method, and a new crack evaluation index, CI, was proposed. The master curve constructed based on CI can be used to characterize the development of specimen cracks over a larger range of load levels. The fatigue crack propagation equation based on the CI coupling fatigue process, strain level, and temperature can accurately predict the crack propagation process in cylindrical specimens. Using CI and fatigue crack propagation indicators under different test conditions is significant for predicting crack propagation during shear fatigue testing.

The pursuit of robust research methodologies to forecast the rutting sensitivity of asphalt mixtures and pavements remains a challenge for the industry. An in-depth examination of the rutting behaviour of asphalt mixtures and pavements under varying influencing factors was conducted via indoor experiments and finite element simulations to investigate the evolution of rutting. This study leverages high-temperature test data derived from multiple stress creep recovery tests of asphalt mortar, complemented by pertinent theories (Burgers model) as the constitutive model. At the same time, a contact law is defined based on the thickness of the asphalt binder layer and increases the accuracy of the rutting simulation. Generate random aggregate asphalt mixture and surface layer models using Python scripts in finite element software. The results show that the simulation results are consistent with the experimental results, and the overall measured amplitude on site is lower than the numerical simulation value. Furthermore, the model parameters will be applied to a microscopic pavement model to study the mechanical response and rutting development of pavement structures under thermal-mechanical coupling. The meso numerical simulation method developed in this study serves as an effective tool for unraveling the high-temperature failure mechanism of asphalt mixtures.

Owing to their diverse applications, TiO2-nanoparticles have been extensively discharged into the aquatic environment, posing serious threats to aquatic life and human health. Meanwhile, the aquatic organisms such as cyanobacteria affect the mobility and fate of the nanoparticles, in turn, these aquatic organisms also may be influenced by the nanoparticles, and which further elicits more hazard to ecosystem. In this study, the different concentration of TiO2 nanoparticles were added into the algal solution to observe the status of TiO2 nanoparticles and assess their influences, especially for photocatalytic toxicity on algal growth. The results demonstrated that algal cells and extracellular polymeric substances (EPS) simultaneously affected the TiO2 aggregation and settling in algae culture. In addition, TiO2 NPs inhibited the growth of algal cells through the multiple effects on the light adsorption, photosynthetic activity, oxidative stress and lipid peroxidation. Particularly, the reactive oxygen species generated by photoactive TiO2 NPs caused the changes of EPS and microcystin-LR (MC-LR) release, and these extracellular matters were crucial intermediate to the state of TiO2 NPs and algal cells growth. This study will not only be significant for understanding TiO2 behavior in the real aquatic environment but also be helpful for exploring the effects of TiO2 nanoparticles on cyanobacteria, especially for the released extracellular matters.

Accurately predicting the rutting development law of asphalt pavement is of great significance for preventing and controlling pavement diseases. The aggregate skeleton of the asphalt mixture is the main load-bearing part and plays an important role in its anti-rutting performance. However, quantitative and mesoscopic evaluation indicators and standards for aggregate skeletons have not been established. This study aims to reveal the relationship between the mesostructured characteristics of asphalt mixtures and rutting damage. This paper uses two-dimensional image technology to analyze the dynamic change process of internal skeleton information of two graded asphalt mixtures under cyclic wheel load. According to the fractal theory, the fractal dimension and multifractal spectrum of the full-depth aggregate were calculated. The results indicate that the linear regression model between the mesoscopic skeleton information of asphalt mixture and the average rutting depth during the rutting test can be used to quantify the rutting performance. There is an obvious correlation between the fractal dimension of the section aggregate and the loading times, and there is a certain linear relationship between the multifractal spectrum indexes and the loading times. It indicates that the fractal theory index of aggregate can reflect the change of the macro performance of loading times.

Owing to their diverse applications, TiO2-nanoparticles 2-nanoparticles have been extensively discharged into the aquatic environment, posing serious threats to aquatic life and human health. Meanwhile, the aquatic organisms such as cyanobacteria affect the mobility and fate of the nanoparticles, in turn, these aquatic organisms also may be influenced by the nanoparticles, and which further elicits more hazard to ecosystem. In this study, the different concentration of TiO2 2 nanoparticles were added into the algal solution to observe the status of TiO2 2 nanoparticles and assess their influences, especially for photocatalytic toxicity on algal growth. The results demonstrated that algal cells and extracellular polymeric substances (EPS) simultaneously affected the TiO2 2 aggregation and settling in algae culture. In addition, TiO2 2 NPs inhibited the growth of algal cells through the multiple effects on the light adsorption, photosynthetic activity, oxidative stress and lipid peroxidation. Particularly, the reactive oxygen species generated by photoactive TiO2 2 NPs caused the changes of EPS and microcystin-LR (MC-LR) release, and these extracellular matters were crucial intermediate to the state of TiO2 2 NPs and algal cells growth. This study will not only be significant for understanding TiO2 2 behavior in the real aquatic environment but also be helpful for exploring the effects of TiO2 2 nanoparticles on cyanobacteria, especially for the released extra- cellular matters.

With the development of industry, agriculture, and aquaculture, excessive ammonia nitrogen mainly involving ionic ammonia (NH4+) and molecular ammonia (NH3) has inevitable access to the aquatic environment, posing a severe threat to water safety. Photocatalytic technology shows great advantages for ammonia nitrogen removal, such as its efficiency, reusability, low cost, and environmental friendliness. In this study, CP (g-C3N4/CoP) composite materials, which exhibited high-efficiency ammonia nitrogen removal, were synthesized through a simple self-assembly method. For the optimal CP-10 (10% CoP) samples, the removal rate of ammonia nitrogen reached up to 94.8% within 80 min under visible light illumination. In addition, the nitrogen selectivity S(N2) is about 60% for all oxidative products. The high performance of the CP-10 photocatalysts can be ascribed to the effective separation and transmission of electron–hole pairs caused by their heterogeneous structure. This research has significance for the application of photocatalysis for the remediation of ammonia nitrogen wastewater.

建设依托网络信息技术的线上教学与传统线下教学相融合的高质量本科课程是推进课程改革创新的重要工作,是培养创新型、应用型人才的根本保证."水质工程学Ⅱ"是给排水科学与工程专业重要的学科技术基础课.为提高课程教学质量,文章对"水质工程学Ⅱ"课程进行了线上线下混合式教学模式改革,从线上教学资源建设、考核评价机制及教学手段与方法改革等方面进行了实践探索,针对实施改革过程中所发现的问题提出了改进措施.

Paraffin（PA） was used as the phase change material and modified fly ash（mFA）treated by acid leaching method as the encapsulation matrix, and PA/mFA form-stable phase change material was prepared by vacuum impregnation process. The chemical compatibility and phase change thermal properties of PA/mFA form-stable phase change material were studied by melt leakage test,FT-IR,DSC,and heat storage and release performance test. The results show that when the mass ratio of paraffin to fly ash is m（PA）∶m（mFA）=1∶4,PA/mFA form-stable phase change material has no leakage of melt PA,and PA and m FA are physically blended. The phase transition temperature of PA/mFA form-stable phase change material is 22.6 ℃,conforming to the comfortable temperature of the human body,the phase change latent heat is 41.3 J/g. The temperature change during melting and solidification of PA/mFA form-stable phase change material lag significantly behind the change of ambient temperature.

Phase change material (PCM) applied in buildings can significantly improve thermal comfort and realize building energy conservation. In recent years, double-layer shaped phase change wallboards (DLSPCWs) that depends on the latent heat absorption and release of two kinds of PCMs can effective control the indoor temperature fluc-tuation, and have been play an important role in improving the indoor thermal environment. The related re-searches show that, it is rare but necessary to optimize the DLSPCWs in different typical climate areas in order to further promote the application development of PCMs in buildings for energy conservation. Aimed this, fifty-four different DLSPCWs were constructed in this study by selecting different phase change thermal storage layer from four kinds of form-stable PCMs and changing the thickness of the layer to optimize the structure of DLSPCW in two typical climate areas, including severe cold area (Xining city, China) and hot summer and warm winter area (Haikou city, China) respectively. Comsol Multiphysics was used for heat transfer simulation and calculation of the DLSPCW in order to determine its best structure combination pattern for the two areas, and DesignBuilder for comparing and analyzing the building energy conservation effect when using the optimal DLSPCW in buildings. Compared with the ordinary wall, the optimized DLSPCW saved 14,198.96 kW center dot h electric energy during the heating period in Xining, while 18,816.62 kW center dot h electric energy in Haikou during the cooling period. The results proved that the optimum structure of the DLSPCW not only reduced the heating load and the cooling load but realized the maximum utilization of the PCMs.

以膨胀珍珠岩为载体,吸附相变石蜡后利用白乳胶封装定型,制备了2种不同相变温度和相变潜热的石蜡基相变蓄热板.测试了相变蓄热板的热物性参数、比热容及不同包覆率下石蜡基相变蓄热板的导热系数.结果表明,该类相变蓄热板具有适宜建筑节能的相变温度和潜热及形状保持能力,40℃时出现最大比热容,为2.694 J/(g·K),导热系数随白乳胶包覆率的增加而降低.采用石蜡基相变蓄热板构建多温度组合型相变蓄热围护结构,并对其建筑控温效果进行了实验模拟和DesignBuilder软件模拟研究,结果表明,多温度组合式相变蓄热板作为建筑围护结构使用时可起到隔热控温作用,从而达到降低建筑能耗的目的.

基于数值解模型的焓法模型与显热容法模型是时下最主要的分析相变传热特性方法,综述了目前这2种方法在不同相变储能领域的应用现状,并分析了各自应用的优缺点与分别更适应于何种计算情况,总结了目前这2种方法在计算建筑相变蓄热时的局限,为之后在相变材料传热过程进行数值模拟提供了参考.

与单层定型相变墙体相比,双层定型相变墙体依靠两层相变材料的潜热吸收和释放,可实现对室外冷热量的有效控制,发挥更加显著的改善室内热环境的作用.以课题组近年来制备的4种不同相变温度和潜热的定形相变材料为保温基材,构建具有两种不同相变保温层的双层定型相变蓄热墙体,基于相变传热特性数值模拟的显热容法,建立双层定型相变墙体传热数值模型并利用COMSOL Multiphysics数值分析软件求解.针对夏热冬冷与严寒地区使用双层定型相变墙体的温度控制效果进行模拟,对双层定型相变墙体的传热过程及控温效果的影响因素进行分析,为优化双层定型相变墙体的组合形式提供参考.

The composite phase change material (PCM) consisting of phase change paraffin (PCP) and polymethyl methacrylate (PMMA) was prepared as a novel type of shape-stabilized PCM for building energy conservation through the method of bulk polymerization. The chemical structure, morphology, phase change temperature and enthalpy, and mechanical properties of the composite PCM were studied to evaluate the encapsulation effect of PMMA on PCP and determine the optimal composition proportion. FTIR and SEM results revealed that PCP was physically immobilized in the PMMA so that its leakage from the composite was prevented. Based on the thermo-physical and mechanical properties investigations, the optimal mass fraction of PCP in the composite was determined as 70%. The phase change temperature of the composite was close to that of PCP, and its latent heat was equivalent to the calculated value according to the mass fraction of PCP in the composite. For estimating the usability in practical engineering, thermal stability, reliability and temperature regulation performance of the composite were also researched by TG analysis, thermal cycling treatments and heating-cooling test. The results indicated that PCP/PMMA composite PCM behaved good thermal stability depending on the PMMA protection and its latent heat degraded little after 500 thermal cycling. Temperature regulation performance of the composite before and after thermal cycling was both noticeable due to its latent heat absorption and release in the temperature variation processes. The PCP/PMMA phase change plate was fabricated and applied as thermal insulator in miniature concrete box to estimate its temperature regulation effect under the simulated environmental condition. It can be concluded that this kind of PCP/PMMA shape-stabilized PCM with the advantages of no leakage, suitable phase change temperature and enthalpy, good thermal stability and reliability, and effective temperature regulation performance have much potential for thermal energy storage in building energy conservation.

Neopentyl glycol is a kind of solid-solid phase change material for thermal energy storage. In order to overcome volatilization weight loss caused by the high saturated vapor pressure of neopentyl glycol, epoxy resin was chosen as the encapsulation matrix to inhibit the volatilization of neopentyl glycol when it happens phase change or works in a relatively high temperature environment. The micro morphology analysis indicated that the neopentyl glycol was encapsulated evenly in the epoxy resin matrix. These two components had no chemical reactions and combined with each other by the physical encapsulation. Phase change temperature and latent heat of the composite was measured as 41.26°C and 57.04 J/g respectively, which proves the thermal heat storage performance of the neopentyl glycol was not influenced by the adding of epoxy resin. Meanwhile, attributed to the effective encapsulation and protection by epoxy resin, volatilization weight loss of the neopentyl glycol in the composite decreased significantly and behaved good thermal stability and reliability. After 100 times thermal cycling test, the composite hardly changed in the thermo-physical properties. Thus, the prepared neopentyl glycol/epoxy resin composite phase change material is supposed to be a potential and promising functional material for the applications in low temperature building energy conservation and solar energy storage.

The aim of this study is to prepare a form-stable phase change material (PCM) with capric and lauric fatty acid (CA-LA) eutectic as the heat absorption material and diatomite filter aid as the supporting matrix. The method of vacuum impregnation was conducted to prepare the composite PCM which has high thermal performance. Its characteristics such as microstructure, thermo-physical propertiesand thermal stability were investigated by SEM, FT-IR, DSC and TG technique. The adsorption capacity of diatomite filter aid to CA-LA eutectic was 49wt%, and the composite PCM kept solid in macro-level even when the CA-LA melted due to the capillary and surface tension forces of diatomite filter aid. DSC analysis showed that phase change temperature and latent heat of the form-stable PCM was 21.8. and 75.45 J.g-1respectively. TG analysis indicated that the diatomite filter aid particles absorbed and constrained the CA-LA molecules in the pores and confirmed the form-stable property of the composite. After 100 times thermal cycling, the phase change temperature and latent heat of the form-stable PCM respectively decreased by 0.9% and 1.1%, which can be neglectable in the practical engineering application.

相变控温砂浆可以借助相变材料的相变潜热和热工性能来改善建筑围护结构的保温性能,以癸酸-月桂酸二元低共熔物/改性硅藻土定形相变材料为相变蓄热介质,采用共混搅拌法掺入水泥砂浆中,制成相变控温砂浆.利用FT-IR、DSC等测试了相变砂浆化学结构及热物性,并测试了相变控温砂浆的热工参数,通过实验模拟和DesignBuilder软件模拟研究了相变砂浆用作保温材料的建筑调温效果.

解决资源短缺、环境持续恶化等问题是目前科学研究的重要课题.建筑能耗是社会能源消耗的主要来源,将相变材料应用于建筑中可以起到节约建筑能耗的作用,近年来受到相关人员的高度重视.相变材料的建筑节能应用形式主要包括应用在建筑围护结构中的被动式节能与提升建筑设备能源利用率的主动节能两方面.综述了近年来相变材料在建筑中的应用与研究进展,以期为日后相关工作的进行提供帮助.