The green chemistry method for analyzing changes in the concentration of substances during a reaction process is an energy-saving and interesting experimental process. In this paper, the performance of electrolysis of methylene blue (MB) in NaCl electrolyte was studied using a smartphone-based paper microzones method (PMZs), and paper microzone platform was made by discarded label stickers. The linear range spanned from 1.25 mg/L to 15 mg/L for the concentration-absorbance correspondence measured via spectrophotometry, and from 1.25 mg/L to 17.5 mg/L for the concentration-R-value correspondence measured via the PMZs method. The findings revealed that the limit of detection (LOD) value of the PMZs method was 0.494 mg/L, and the limit of quantification (LOQ) value was 1.497 mg/L. Moreover, the accuracy ranking of the measured MB electrolytic change process across different channels was as follows: Red>Grey>Green>Blue. PMZs method also showed well reliability in measuring actual dye polluted wastewater. The results demonstrate the sensitivity and precision of the PMZs method, as indicated by the low LOD and LOQ values. Additionally, the accuracy ranking provides valuable insight into the performance of the method across different color channels, shedding light on the potential applications and limitations of the PMZs technique in color-based electrochemical analyses. The electrolysis reaction led to a red-shift in the absorption characteristics of MB in NaCl electrolyte, resulting in a notable change in its light absorption properties. This information is crucial for researchers and practitioners seeking to employ the PMZs method for accurate and reliable color measurements in various scientific and industrial settings.

Background: Tetracycline (TC), a commonly used antibiotic, is extensively utilized in the medical sector, leading to a significant annual discharge of tetracycline effluent into the water system, which harms both human health and the environment. Objective: A novel technique was developed to address the issues of photogenerated carrier complexation and photocatalyst immobilization. Compared to traditional photocatalytic photoelectrodes, the suspended catalyst used in the photovoltaic synergy field is more stable and increases the solidliquid contact area between the catalyst and the pollutant. Methods: This paper uses sol-gel-prepared Ag-TiO2 materials for the photoelectric synergistic fieldcatalyzed degradation of TC. The study examined how the Ag doping ratio, calcination conditions, catalyst injection, pH, electrolytes, and electrolyte injection affected photoelectric synergistic fieldcatalyzed degradation. The experiments were performed in a photocomposite field with a constant 50 mA current and a 357 nm UV lamp for 60 minutes. The composites underwent characterization using XRD, TEM, and XPS techniques. Results: Ag-TiO2 photoelectric synergistic field-catalyzed reaction with 357 nm ultraviolet lamp irradiation for 60 min and a constant current of 50 mA degraded 5 mg/LTC under preparation conditions of molar doping ratio of Ti: Ag=100:0.5, roasting temperature of 500 °C, and roasting time of 2 h. The photoelectric synergistic field-catalyzed degradation process achieved a degradation rate of 90.49% for 5 mg/L TC, surpassing the combined degradation rates of electrocatalysis and photocatalysis. The quenching experiments demonstrated that the degradation rate of TC decreased from 90.49% in the absence of a quencher to 53.23%, 42.58%, and 74.52%. The presence of •OH had a more significant impact than h+ and •O2 -. Conclusion: The findings suggest that Ag-TiO2 significantly enhanced the efficacy of photoelectric synergistic field-catalyzed degradation and can be employed to treat high-saline and lowconcentration TC. This establishes a benchmark for using photoelectrocatalytic materials based on titanium in treating organic wastewater.

Both g-C3N4 and Bi2O2CO3 are good photocatalysts for the removal of antibiotic pollutants, but their morphological modulation and catalytic performance need to be further improved. In this study, the calcination-hydrothermal method is used to prepare a O-g-C3N4@Bi2O2CO3 (CN@BCO) composite photocatalyst from dicyandiamide and bismuth nitrate. The prepared catalyst is characterized through various methods, including X-ray diffraction (XRD) and transmission electron microscopy (TEM). Further, the effects of different parameters, such as catalyst concentration and initial pH of the reaction solution, on its photocatalytic activity are investigated. The results show that the CN@BCO sample achieves an optimal degradation rate of 98.1% for tetracycline hydrochloride (TCH) with a concentration of 20 mg/L and a removal rate of 69.4% for total organic carbon (TOC) at 40 min. The quenching experiments show that ·O2-, h+, and ·OH participate in the photocatalytic process, with ·O2- being the most dominant active species. The toxicity of the predicted TCH degradation intermediates is analyzed using Toxicity Estimation Software Tool (TEST). Overall, the CN@BCO composite exhibits excellent photocatalytic performance, making it a promising candidate for environmental purification and wastewater treatment.

为探究悬挂式轨道列车火灾时不同疏散模式对人员安全性的影响,首先基于竖向疏散模式的特性,构造人员下行速度与楼梯高度、坡度的耦合关系式;然后采用Pathfinder软件,分析不同疏散模式下疏散设施参数与人员必需安全疏散时间(tR)的关系.结果表明:采用竖向设施的疏散方式,tR与列车距地面的高度呈正相关关系,独立楼梯、充气滑梯均满足安全疏散要求;采用双充气滑梯的疏散方式,tR比采用单个充气滑梯的tR减小约35.6％;独立楼梯坡度设计宜为30～35°、宽度不小于1.3m;横渡板宽度优选1.5 m,疏散平台宽度不小于1.3 m;疏散平台+楼梯组合疏散,楼梯间距为200 m时,列车在区间任意位置的tR约等于415 s,小于900 s,满足安全疏散要求.从经济性和可持续性角度,推荐采用独立楼梯为主、其他设施为辅的疏散方式.

The complex characteristics of long-distance highway tunnels may lead to serious loss of life and property in fire incidents. According to the statistical analysis, heavy goods vehicle (HGV) is one of the primary risk factors for tunnel fires. In this study, a quantitative risk assessment model of HGV-involved tunnel fires is established based on the functional resonance analysis method (FRAM) and Bayesian network (BN). Using FRAM, the mechanisms of the incident occurrence and evolution and critical risk factors of HGV-involved tunnel fires are determined, and the BN model is used to quantify the risk based on a probabilistic analysis. Focusing on operational management, monitoring system construction, type of transporting goods, emergency rescue, and egress facilities, the incident severity is determined in terms of casualties and economic losses. The proposed risk assessment method is expected to assist the tunnel operational management and the fire services in identifying critical risk factors in HGV-involved tunnel fires.

With an appropriate air supply, smoke can be controled by water curtain system effectively in an urban underground road. In this study, smoke blocking efficiency and water curtain momentum ratio are newly introduced. These parameters are used to quantitatively characterize the effects of smoke control and thermal insulation. Numerical simulation method is used in this paper. The results indicate the following: the smoke efficiency decreases as water spray intensity increases, and when the water spray intensity is 0.5L/(m.s), increasing the water spray intensity by 0.5L/(m.s) may be beneficial to increase the smoke blocking performance. The smoke blocking efficiency and the thermal insulation efficiency decrease first and then increase along with the increase in the momentum ratio R. Better smoke blocking and heat insulation performance occured when R <= 2. In this condition, the visibility at the 2 m above the floor is above 10 m, and the temperature is lower than 60 ?. It can ensure the safe evacuation of the trapped people.

The wooden materials used in historic buildings are quite different due to the influence of local climate and environment. In order to have a deep understanding of influence of wood species on the upward flame spread performance, a series of tests were conducted to obtain the profile of mass loss rate (MLR), flame spread rate (FSR), total burning duration (TBD), and the maximum flame characteristic length (MFL) by using a traditional flame spreading measurement facility. During the tests, beech wood, fir wood, pine wood, camphor wood and elm wood were selected as typical samples. The results and discussion indicate that wood species imposed a strong effect on the flame spread performance. The total burning duration (TBD) of wood with high moisture content and high solidity is significantly higher than that of other types of wood. Softwoods with higher lignin content and lower hemicellulose can increase the flame spread rate (FSR) to a certain extent. And also the higher the moisture content of wood can lead to the lower the corresponding mass loss rate. Based on discussion, the fire risks of different wood species are also ranked in this paper.

Methods of electrochemical correlation are becoming more complex and costly with the lack of a simple electrolytic analysis method. Herein, an interesting analysis of the performance of electrocatalytic degradation of different dyes was carried out using a modified paper microzones method (PMZs) performed with a smartphone, and data from spectrophotometers were used for comparative analysis. At the same voltage and in the same reaction cell, the same mass of sodium sulphate, acetic acid and pure water were added according to the strength of the electrolyte to degrade methyl orange(MO), fuchsin basic(FB), methylene blue(MB) and the mixture of these dyestuffs. When measured by the PMZs method, the correlation coefficients were above 0.9 in the concentration range of 5-50 mg/L, the range of variation of LOD values was 3.843-9.561 mg/L and the range of variation of LOQ was 11.646-28.973 mg/L. When measured by the spectrophotometric method, some of the dyes only had a greater correlation in the range of 5-40 mg/L. The range of variation of LOD values was 0.900-9.213 and the range of variation of LOQ was 2.727-27.917 mg/L. When FB was used as a degradation object, the decrease in absorbance at 80 min was 21.83%, 35.93%, 60.90% and the increase in grey value was 0.40%, 3.04%, 3.25% under the conditions of electrolytes only water, CH3COOH, Na2SO4, respectively, and maintained P less than 0.05 at different moments. Hence, the related results contribute to the further application and development of green chemistry PMZs in electrochemical analysis and environmental science.

为提高消防站规划选址的科学性,合理调度有限的消防应急资源,提升消防应急响应效率,以湖北省某城市中心城区为研究对象,在火灾风险评估基础上,对消防站选址模型进行优化研究,构建了 MCLP-BACOP 结合覆盖模型并借助 ArcGIS软件对模型进行优化求解.研究结果表明:通过 MCLP-BACOP 结合覆盖模型计算得到的中心城区消防站选址方案在对覆盖率影响较小的情况下,可以减少消防站数量并降低成本,同时能保证高风险区重复覆盖.该模型对于火灾风险较大的城区适用性强,在考虑经济因素及现实条件下,可有效提升城区消防响应效率.