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.

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.

Risk assessment of hazardous materials transportation:A review of research progress in the last thirty years

In recent years,hazardous materials transportation accidents occur frequently,causing huge casualties and property losses.Risk assessment of hazardous materials transportation has been constantly investigated by researchers and decision-makers.In order to study the research progress of risk assessment of hazardous materials transportation,so as to better reveal relevant problems.This review systematically analyzes the existing literature,from 1991 to 2020,on risk assessment models and methods of hazardous materials transportation,and segregates the relevant studies based on unimodal and intermodal transportation systems.Additionally,an example is considered to analyze the characteristics of each risk assessment model of unimodal transportation,and a novel detailed classification is proposed for the risk assessment problems.The results indicate that the research on the risk assessment model of road transportation of hazardous materials is comprehensive,whereas that based on the railway and intermodal transportations is deficient.In comparison with the traditional risk assessment model,the conditional value-at-risk model presents a flexible decision-making framework for decision-makers and controls risk preference between risk neutrality and risk aversion.Owing to the difficulty in achieving door-to-door railway transportation and the increased risks associated with the intermodal transportation,the conclusion that the risk of railway and multimodal transportation of hazardous materials is lower than that of road transportation is not universal.Transport operators and governments can combine the advantages of different transportation modes,such as low risk,low cost,high flexibility,and high reliability,to achieve public safety and improve the competence of the system.Based on the proposed classification,this review identifies the existing trends and research gaps and summarizes future research directions.

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.

Drone Applications for Preventing and Responding HAZMAT Disaster

Introduction: This article describes some possibilities of drone applications for pre-venting and responding hazardous materials disasters. Methods: Apart from reviewing the little professional literature available, the author relied on his own practical expe-rience and adopted other researchers’ related findings. He also applied logical reason-ing, systematization as well as adopting an economic approach—to assess efficiency. Results: There are two basic possibilities for the use of drones in the field of chemical disasters: one is for prevention to support the work of authorities, while the other is connected to the response to accidents or disasters. To summarize the research find-ings, the author explored the typical possibilities for use, illustrating with actual exam-ples to prove their usefulness, identified certain risks and made recommendations on further researches.