Flexible SERS substrates for hazardous materials detection: recent advances

This article reviews the most recent advances in the development of flexible substrates used as surface-enhanced Ra-man scattering(SERS)platforms for detecting several hazardous materials(e.g.,explosives,pesticides,drugs,and dyes).Different flexible platforms such as papers/filter papers,fabrics,polymer nanofibers,and cellulose fibers have been investigated over the last few years and their SERS efficacies have been evaluated.We start with an introduction of the importance of hazardous materials trace detection followed by a summary of different SERS methodologies with par-ticular attention on flexible substrates and their advantages over the nanostructures and nanoparticle-based solid/hybrid substrates.The potential of flexible SERS substrates,in conjunction with a simple portable Raman spectrometer,is the power to enable practical/on-field/point of interest applications primarily because of their low-cost and easy sampling.

Organic Materials Could Improve the Phytoremediation Efficiency of Soil Potentially Hazardous Metal by Sedum alfredii Hance

Soil potentially hazardous metal(PHM)is continually attracting public attention worldwide,due to its highly toxic properties and potentially huge damage to human being through food chain.Phytoremediation is an effective and eco-friendly way in remediation technology.A pot experiment was carried out to investigate the effect of different organic materials(biogas residue(BR),mushroom residue(MR),and bamboo-shoot shell(BS))application on phytoremediation of two PHM-contaminated soils(Fuyang soil as‘heavily-polluted soil’and Wenzhou soil as‘moderately-polluted soil’,respectively)by Sedum alfrecdii Hance.The results indicated:1)for moderately-polluted soil,the 5%BR treatment had the strongest activation to Cu and Zn,for heavily-polluted soil,1%BS treatment had the highest activation effect for Cu,Zn,Pb and Cd.2)the above-ground biomass of Sedum alfredii Hance increased with the addition rate of organic materials.3)for Cd uptake of Sedum alfredii Hance in moderately-polluted soil,only 1%BS treatment had a better accumulation effect,compared to the control,for Zn element,MR treatments were weaker than the control,while other treatments were better than the control,of which 5%BR,1%BS and 5%BS accumulated more Zn element by 39.6%,32.6%and 23.8%,respectively;in heavily-polluted soil,the treatments of 5%BS,1%BR and 5%BR accumulated more Cd than the control by 12.9%,12.8%and 6.2%,respectively,the treatments with organic materials addition promoted Zn accumulation in shoots of Sedum alfredii Hance,and the best treatment was 5%BS.Therefore,an appropriate application rate of BS and BR could improve the remediation efficiency for Zn/Cd contaminated soils by Sedum alfredii Hance.

Natural Radioactivity Measurement and Assessment of Radiological Hazards in Some Building Materials Used in Bangladesh

The radioactivity concentrations of 226Ra, 232Th and 40K in 24 samples of natural and manufactured building materials commonly used in Bangladesh were measured using HPGe gamma ray spectrometer. The results in the present study were compared with the world average and also with the reported data available in literature. The radium equivalent activity, the absorbed dose rate, annual effective dose, external and internal hazard indices, gamma index, alpha index, annual gonadal dose equivalent and excess lifetime cancer risk were also evaluated to assess the potential radiation hazards associated with these building materials. All samples under investigation were found to be within the recommended safety limit and do not pose any significant radiation hazards. This study can be used as a reference for more extensive studies of the same subject in future.

Natural radioactivity levels and radiation hazards for gypsum materials used in Egypt

Radionuclides naturally occurring in building materials may significantly contribute to the annual doses to the public. For instance, familiar building materials such as the concrete and gypsum board have been reported to produce a dose of about 0.04 mSv per year for a typical person (NCRP 1987c). External as well as internal exposures are two pathways of radiation dose imparted to human beings from the building materials. As information on the radioactivity of such materials is lacking, the study of gypsum materials used in Egypt was carried out in order to estimate the annual dose to the Egyptian population due to natural radionuclides in building materials. During the study, 18 samples of commonly used gypsum raw materials were collected and measured. The activity concentrations were determined by gamma ray spectrometry. Their mean values were in the ranges of 499.29 ± 11.53 Bq·kg-1 for 40K, 91.97 ± 2.61 Bq·kg-1 for 226Ra, 37.62 ± 1.67 Bq·kg-1 for 238U and 42.27 ± 2.22 Bq·kg-1 for 232Th. The activity indexed Iγ for 18, different gypsum samples varied from 0.31 ± 0.03 to 2.3 ± 0.19 and the radium equivalent activity (Raeq), from 38.81 ± 1.68 to 324.7 ± 9.42. These values are lower than the limit of 370 Bq·kg-1 adopted by the Organization for Economic Cooperation and Development (OECD). The average indoor annual effective gamma dose rate (DE) in (mSv/y) for the people, caused by the building materials of dwellings, was assessed for most commonly gypsum materials. It was estimated to be in the range from 0.10 ± 0.003 mSv/y to 0.74 ± 0.08 mSv/y. The internal and external hazard indices (Hin, Hex) and the absorbed dose rate in air D in each sample were evaluated to assess the radiation hazard for people living in dwelling made of the studied materials. The absorbed dose rate of indoor air in samples G1, G2, G11, G17 and G18 is less than the international recommended value which is 55 nGyh-1. While the absorbed dose rate for samples G3, G4, G5, G6, G7, G8, G9, G10, G12, G13, G14, G15 and G16 is higher than 55 nGyh-1, these samples are not acceptable for use as building materials.

Geophysical Investigation of the Triassic Salt Material Hazard: El Fahs Case Example (Northern Tunisia)

The Tunisian territory (area of diapirs) is exposed to the risks of ground movements linked to water, some of which are related to the phenomenon of dissolution of gypsum, allowing the appearance of underground cavities which present natural risks and set people in danger. The analysis of the hazard was determined by the field study coupled with the application of geophysical methods to locate and map the cavities and identify their dimensions and their positions in the subsoil. In the region of El Fahs (40 km NW of Tunis): we used a non-destructive method, georadar (GPR) with a 200 MHz antenna band-width, and an electric method, by using the electric tomography of which we have applicated the sequence of dipole-dipole measurement. The results ob-tained were examined and interpreted according to 2D profiles. The geophysi-cal methods of GPR and electrical tomography aim to detect many calvities in different depths. However, the geological radar was able to identify several cavities and the zones of dissolution whose investigation depth did not exceed the first 3 meters. On the contrary, the electric tomography method allowing the presence of several deeper underground cavities with larger dimensions ex-tended to 64 meters. To conclude, the geological and hydrogeological contexts of the terrain studied and on the state of the soil and subsoil allow us to better understanding the mechanisms of the establishment of the dissolution phe-nomenon and the appearance of cavities in the basement. The analysis of the predisposing factors present in the study area shows that the geodynamic con-text of the Triassic ascent takes place according to a precise thermodynamic process that favors the phenomenon of dissolution of the gypsum.

Experimental and Simulated Effective Dose for Some Building Materials in France

The specific radioactivity of several building materials used in France, which is considered a direct exposure to radiation, has been assessed by γ-ray spectrometry. Corrected for coincidence summing and self-absorption effects, the values for 226Ra, 232Th and 40K were in the ranges 4 - 56, 3 - 72 and 9 - 1136 Bq·kg-1, respectively. The samples were found to have radium-equivalent activities between 5 and 245 Bq·kg-1. Values of 0.02 - 0.67 for the external and 0.03 - 0.82 for the internal hazard indexes were estimated. The calculated absorbed dose in air agrees closely with MCNPX simulations. The conversion of absorbed dose to annual effective dose gave values between 0.03 - 1.09 mSv·y-1. All these values are below action limits recommended by the International Commission on Radiological Protection. The materials examined would not contribute a significant radiation exposure for an occupant and thus are acceptable for construction.

Investigation on 226Ra, 238Th, 4040K and 137Cs Concentrations in Common Polishing Materials Consumed by Inhabitants in Saudi Arabia

Knowledge of radioactivity present in polishing materials enables one to assess any possible radiological risks to human health. In this work, the radioactivity due to the presence of 226Ra, 232Th, 40K, and 37Cs has been measured in polishing materials con-sumed in Saudi Arabia using gamma spectrometry with HPGe. The activity concentra-tions of 226Ra, 232Th, 40K and 137Cs ranged from 13.61 ± 0.005 to 0.60 ± 0.002, 18.43 ± 0.003 to 0.78 ± 0.001, 342.59 ± 0.009 to 2.47 ± 0.001 and 1.47 ± 0.001 to 0.55 ± 0.001 Bq/l, respectively. For 226Ra and 40K, the highest values are measured in stainless steel polisher. The highest values also measured in metal polisher (copper-chrome) and disinfectant cleaner and polisher sample for 232Th and 137Cs. Radium equivalent activ-ity due to the natural radioactivity of the investigated samples ranged from 51.37 to 1.24 Bq/l. This value is less than the recommended values in the established standards. The evaluated data were compared with the literature data. Our results indicate that no significant radiological hazards arise from using investigated samples hence quite safe to be used as polishing materials.

Emergency Logistics Management for Hazardous Materials with Demand Uncertainty and Link Unavailability

Due to its harmful nature,any incident associated with hazardous material(hazmat)may cause tremendous impacts on the surrounding people and the environment.Focusing on the incident involving this specific type of good,we develop a reliable and robust emergency logistics network that considers both demand uncertainty and possible unavailability of particular links.A time-based risk measure is carefully designed upon the traditional risk assessment to reflect the stakeholder’s sensitivity to risk over response time.The disruption and uncertainty are modeled as two sets of scenarios which are integrated into a bi-objective robust model to evaluate the trade-offs between risk and cost.The effectiveness of the emergency response can be assured by expenditures that add extra capacities to certain links or establish additional facilities that aid recovery from incidents.We apply our model and approach to a real-world network in Guangdong China.Analytical results reveal the necessity of embedding consideration of uncertainty and unreliability into emergency network design problems;outline the importance of hedging against unpredictability by system redundancies;and indicate the impact of stakeholder’s orientation towards cost and risk on the location,allocation,and routing decisions in hazmat emergency response.

Enhancing safety and efficiency in automated container terminals: Route planning for hazardous material AGV using LSTM neural network and Deep Q-Network

As the proliferation and development of automated container terminal continue,the issues of efficiency and safety become increasingly significant.The container yard is one of the most crucial cargo distribution centers in a terminal.Automated Guided Vehicles(AGVs)that carry materials of varying hazard levels through these yards without compromising on the safe transportation of hazardous materials,while also maximizing efficiency,is a complex challenge.This research introduces an algorithm that integrates Long Short-Term Memory(LSTM)neural network with reinforcement learning techniques,specifically Deep Q-Network(DQN),for routing an AGV carrying hazardous materials within a container yard.The objective is to ensure that the AGV carrying hazardous materials efficiently reaches its destination while effectively avoiding AGVs carrying non-hazardous materials.Utilizing real data from the Meishan Port in Ningbo,Zhejiang,China,the actual yard is first abstracted into an undirected graph.Since LSTM neural network can efficiently conveys and represents information in long time sequences and do not causes useful information before long time to be ignored,a two-layer LSTM neural network with 64 neurons per layer was constructed for predicting the motion trajectory of AGVs carrying non-hazardous materials,which are incorporated into the map as background AGVs.Subsequently,DQN is employed to plan the route for an AGV transporting hazardous materials,aiming to reach its destination swiftly while avoiding encounters with other AGVs.Experimental tests have shown that the route planning algorithm proposed in this study improves the level of avoidance of hazardous material AGV in relation to non-hazardous material AGVs.Compared to the method where hazardous material AGV follow the shortest path to their destination,the avoidance efficiency was enhanced by 3.11%.This improvement demonstrates potential strategies for balancing efficiency and safety in automated terminals.Additionally,it provides insights for designing avoidance schemes for autonomous driving AGVs,offering solutions for complex operational environments where safety and efficient navigation are paramount.

食品接触材料中非邻苯类塑化剂迁移及潜在危害的研究进展

近年来,邻苯类塑化剂不断被曝出各式各样的安全隐患问题,其使用已经被严格限制。与此同时,非邻苯类塑化剂由于具有比邻苯类塑化剂更低的毒性,在实际应用中越来越受到厂家的青睐,被广泛使用于食品接触材料当中。然而,伴随着其使用范围的不断拓展以及使用量的持续增加,食品接触材料中非邻苯类塑化剂的迁移情况以及其可能带来的危害绝不能忽视。本文对食品接触材料中非邻苯类塑化剂的相关概念及种类、迁移情况、潜在危害、检测方法进行了综述,旨在为针对食品接触材料中非邻苯类塑化剂进行准确的风险评估提供重要的参考依据。

不确定环境下危险货物公铁联运路径优化研究

为使得危险货物公铁联运路径优化更贴合实际,其引入随机机会约束理论,再用决策分析法、理论研究法和算例分析法等,把含有随机变量的不确定式子转换为确定等价形式,考虑集装箱限容、时间窗约束和运输风险等因素,以运输总成本最低、总时间最短和总风险最小为目标,建立不确定环境下的危险货物多式联运路径优化模型。基于随机模拟算法、神经元网络算法和遗传算法,设计一种改进的混合智能算法验证模型的可行性和有效性。参数变化分析表明:设计的混合智能算法比普通的启发式算法求解效率高;选用大载货量的集装箱对运输企业和风险管理部门均有益;运输途中人口密度或风险阈值越小,可使危险货物运输风险降低;花费较多财力来达到客户的时效要求,也可提高客户满意度;在途运输时间越长,风险值也就越高。以此为运输企业和管理部门提供基础理论知识和多样化的决策方案。

基于风险视角的危险品仓储事故应急物资配置优化

基于风险视角,研究了危险品仓储事故应急物资配置优化问题。提出了应急等待下的危险品风险度量方法,以总成本和总风险最小为目标建立了危险品仓储事故应急物资配置优化模型,应用NSGA-Ⅱ算法对模型进行求解,通过算例验证了方法和模型的有效性。算例计算结果表明,相较于考虑最晚应急时间最小或总应急时间最小的应急物资配置模型,本模型求解出的推荐方案能有效降低总成本和总风险。

危险货物道路运输个性化路径推荐方法

为加强危险货物道路运输风险源头管控,以危货运输车辆行驶轨迹数据为分析对象,研究安全、经济且符合企业自身偏好的道路运输路径优化选择问题,提出了基于偏好、上下文感知的危险货物道路运输个性化路径推荐方法。首先对危货运输车辆历史轨迹数据进行处理,通过提取路径安全和经济性特征学习危货运输企业的路径偏好,在此基础上,综合考虑偏好向量间的距离和方向相似性,提出了改进的K-means偏好聚类算法(improved K-means clustering algorithm based on distance and direction similarity measurement,DDM-K-means),获取了路径偏好类别;其次,依据运输任务执行的时间、天气、运距三方面信息,建立了路径上下文向量,并运用Rock聚类算法划分路径的上下文类别,与路径偏好类别共同构成路径信息;最终,基于神经协同过滤提出了危险货物道路运输路径选择优化算法(optimal route selection algorithm based on neural collaborative filtering,NCF-ORS),得到了危货运输企业对各路径类别的偏好排序,从而为企业推荐最优路径。与基线算法比较分析,结果表明危险货物道路运输个性化路径推荐方法<DDM-K-means,NCF-ORS>,平均绝对百分比误差最低。研究结果有助于挖掘车辆轨迹数据中更多的潜在信息,提升个性化路径推荐能力,可为危货运输企业的选线问题提供决策支持。

化学防护服的防护材料研究进展

化学防护服是抵御危险化学品的重要装备。文章主要介绍了防护服中防护材料的作用原理,梳理了化学防护领域广泛应用的防护材料的发展现状,对比分析了防护材料的原理及防护能力。并指出在多元化的灾害环境下,目前防护材料存在的挑战以及未来研究的方向。

动水条件下煤矿岩体裂隙与管道注浆新型材料性能试验研究

针对煤矿岩体裂隙与管道动水条件下凝结时间长、留存率低、堵水效果差的问题,通过室内试验,研究一种动水条件下煤矿岩体裂隙与管道注浆新型材料及其在动水条件下的材料性能,确定了一种单液浆动水注浆材料,测试了动水注浆材料的凝结时间、流动度、强度和抗冲刷性能,并分析了动水条件下煤矿岩体裂隙与管道注浆新型材料成本。研究结果表明:动水条件下煤矿岩体裂隙与管道注浆新型材料主要由硫铝酸盐水泥、粉煤灰、矿粉、石灰石粉、钢渣粉、可分散性乳胶粉、羟丙基甲基纤维素醚、钠基膨润土、醚类聚羧酸高性能减水剂、白木质素纤维和柠檬酸组成;环境温度为20℃时,初凝时间为40~75 min,通过调节柠檬酸的掺量或增大搅拌时间可延长注浆材料的初凝时间;注浆材料流动度保持在20±3 cm的时间段为10~40 min,失去流动度的时间为15~50 min;水流流速为1.2 m/s时,动水条件下煤矿岩体裂隙与管道注浆材料抗冲刷留存率在85%以上,流速为0.6 m/s时,抗冲刷留存率在90%以上,流速为0.2 m/s时,抗冲刷留存率在95%以上;水胶比0.5∶1的注浆材料1d强度达到7.1 MPa;动水条件下煤矿岩体裂隙与管道注浆材料具有良好的抗动水冲刷性能和低廉的价格,并可根据不同工况调整初凝时间和失去流动度时间,满足煤矿岩体裂隙与管道长距离单液浆注浆堵水需求。

考虑碳排放的危险品运输异构车辆路径问题研究

为满足危险品运输异构车辆路径问题(HVRP)的低碳需求,对易爆危险品运输过程中的总风险、总成本和总碳排放量进行最优化处理。首先,在模型构造阶段,改进总成本与总风险的度量方式,包括建立爆炸事故场景下考虑危险品装载量的风险量化模型,并设计一种用于惩罚成本计算的软时间窗函数,该函数可以优先减少装载量较大的车辆在客户处的等待时间;然后,在算法改良阶段从2方面改进非支配排序遗传算法(NSGA-Ⅱ),设计一种带有改良交叉算子的混合交叉方法来提升全局搜索效率,并通过包含2个阶段的变邻域搜索(VNS)算法来提高局部搜索能力;最后,通过算例验证模型和算法的有效性。研究结果表明:相较于原始NSGA-Ⅱ,改进的算法收敛曲线下降更快,使总成本、总风险和总碳排放量3个优化目标的平均值进一步减少3.36%、12.16%和6.96%;在车辆数目有限的车队中,承运人可以通过选择不同的车辆类型对各目标产生不同程度的影响。

列车火灾隐患分析研究和应用

[目的]火灾事故是地铁运营中主要的安全事故,为将火灾隐患降低至可接受水平,确保列车的安全运行,特进行本研究。[方法]将EN 50126-2:2017《铁路应用-可靠性、可用性、可维护性和安全性(RAMS)的规范和证明第2部分系统安全方法》的安全分析方法应用在城市轨道交通车辆火灾隐患分析中;通过对着火源和易燃物的识别,建立各系统火灾隐患清单;结合HAZOP(危险与可操作性分析)法,对导致火灾发生的部件进行详细分析,并识别火灾发生原因;在车辆设计中对不同场景进行火灾隐患识别,提出减轻措施,并跟踪管理风险解决措施直至风险降低到可接受的水平。[结果及结论]将地铁车辆火灾隐患分析中识别出的火灾区域,应用至火灾仿真分析场景方案中,通过仿真结果对地铁车辆火灾隐患区域进行了再次修正,并将研究结果应用至火灾报警系统设计中,能够更加合理布置火灾报警探测。

复杂地质灾害发育特征及其规律研究

为了将地质灾害的损失降至最低,以某研究区域为背景,对其地质灾害滑坡、崩塌、不稳定斜坡进行分析,分别通过物质组成、目前稳定性、地质灾害规模等方面进行了分类,得出了地质灾害的危害程度,同时通过PFC2D软件进行滑坡的过程分析,得出了滑坡地质灾害的机理,为后续滑坡地质灾害的控制提供一定的参考。

关于高校材料化学类实验室危险化学品安全管理的思考

危险化学品的规范使用是高校实验室安全工作的重点,但有些高校危险化学品管理仍存在一些常见的问题。以天津理工大学新能源材料与低碳技术研究院实验室为例,针对这些问题提出了相应的安全管理策略。从危险化学品管理制度、基础硬件设施、安全培训以及信息化管理等角度探索了高校材料化学类实验室危险化学品安全管理体系新模式,为师生安全、平稳、有序顺利开展教学科研实验提供保障。

热害矿井个体御热装备设计优化与性能研究

针对地下矿山作业地点高温高湿问题,提出应用个体御热装备的解决方案。研发了两款采用相变材料的个体御热装备,采用5类主观评价量表对测试人员的热舒适性、触觉舒适性、服装舒适性、织物手感和可用性进行性能评价。结果表明:①两款御热装备都得到测试人员较好的热舒适性评价,但随着时间推移,受人体汗液蒸发影响,两款御热装备都变得较为潮湿,在除湿性能上仍有待提高;②在测试末段,横插式御热装备在可用性指标上得到较好评价,而竖插式御热装备仅得到略微可用的评价,测试人员负面感受来自相变材料的融化下坠感;③整体来看,测试人员更偏向相变材料采用横插式的御热装备,说明对背心式御热装备的优化研究取得了良好效果。