查看更多>>摘要：Technological advancements in unmanned aerial vehicles(UAVs)have revolutionized various industries,enabling the widespread adoption of UAV-based solutions.In engineering management,UAV-based inspection has emerged as a highly efficient method for identifying hidden risks in high-risk construction environments,surpassing traditional inspection techniques.Building on this foundation,this paper delves into the optimization of UAV inspection routing and scheduling,addressing the complexity intro-duced by factors such as no-fly zones,monitoring-interval time windows,and multiple monitoring rounds.To tackle this challenging problem,we propose a mixed-integer linear programming(MILP)model that optimizes inspection task assignments,monitoring sequence schedules,and charging deci-sions.The comprehensive consideration of these factors differentiates our problem from conventional vehicle routing problem(VRP),leading to a mathematically intractable model for commercial solvers in the case of large-scale instances.To overcome this limitation,we design a tailored variable neighbor-hood search(VNS)metaheuristic,customizing the algorithm to efficiently solve our model.Extensive numerical experiments are conducted to validate the efficacy of our proposed algorithm,demonstrating its scalability for both large-scale and real-scale instances.Sensitivity experiments and a case study based on an actual engineering project are also conducted,providing valuable insights for engineering man-agers to enhance inspection work efficiency.
查看更多>>摘要：Hierarchical networks are frequently encountered in animal groups,gene networks,and artificial engi-neering systems such as multiple robots,unmanned vehicle systems,smart grids,wind farm networks,and so forth.The structure of a large directed hierarchical network is often strongly influenced by reverse edges from lower-to higher-level nodes,such as lagging birds'howl in a flock or the opinions of lower-level individuals feeding back to higher-level ones in a social group.This study reveals that,for most large-scale real hierarchical networks,the majority of the reverse edges do not affect the synchronization process of the entire network;the synchronization process is influenced only by a small part of these reverse edges along specific paths.More surprisingly,a single effective reverse edge can slow down the synchronization of a huge hierarchical network by over 60％.The effect of such edges depends not on the network size but only on the average in-degree of the involved subnetwork.The overwhelming majority of active reverse edges turn out to have some kind of"bunching"effect on the information flows of hierarchical networks,which slows down synchronization processes.This finding refines the current understanding of the role of reverse edges in many natural,social,and engineering hierarchical networks,which might be beneficial for precisely tuning the synchronization rhythms of these networks.Our study also proposes an effective way to attack a hierarchical network by adding a malicious reverse edge to it and provides some guidance for protecting a network by screening out the specific small proportion of vulnerable nodes.
查看更多>>摘要：This study presents a solvent-free,facile synthesis of a bio-based green antibacterial agent and aromatic monomer methacrylated vanillin(MV)using vanillin.The resulting MV not only imparted antibacterial properties to coatings layered on leather,but could also be employed as a green alternative to petroleum-based carcinogen styrene(St).Herein,MV was copolymerized with butyl acrylate(BA)to obtain waterborne bio-based P(MV-BA)miniemulsion via miniemulsion polymerization.Subsequently,MXene nanosheets with excellent photothermal conversion performance and antibacterial properties,were introduced into the P(MV-BA)miniemulsion by ultrasonic dispersion.During the gradual solidifi-cation of P(MV-BA)/MXene nanocomposite miniemulsion on the leather surface,MXene gradually migrated to the surface of leather coatings due to the cavitation effect of ultrasonication and amphiphilic-ity of MXene,which prompted its full exposure to light and bacteria,exerting the maximum photother-mal conversion efficiency and significant antibacterial efficacy.In particular,when the dosage of MXene nanosheets was 1.4 wt％,the surface temperature of P(MV-BA)/MXene nanocomposite miniemulsion-coated leather(PML)increased by about 15 ℃ in an outdoor environment during winter,and the antibac-terial rate against Escherichia coli and Staphylococcus aureus was nearly 100％under the simulated sun-light treatment for 30 min.Moreover,the introduction of MXene nanosheets increased the air permeability,water vapor permeability,and thermal stability of these coatings.This study provides a new insight into the preparation of novel,green,and waterborne bio-based nanocomposite coatings for leather,with desired warmth retention and antibacterial properties.It can not only realize zero-carbon heating based on sunlight in winter,reducing the use of fossil fuels and greenhouse gas emissions,but also improve ability to fight off invasion by harmful bacteria,viruses,and other microorganisms.
查看更多>>摘要：Realizing fast and continuous generation of reactive oxygen species(ROSs)via iron-based advanced oxi-dation processes(AOPs)is significant in the environmental and biological fields.However,current AOPs assisted by co-catalysts still suffer from the poor mass/electron transfer and non-durable promotion effect,giving rise to the sluggish Fe2+/Fe3+cycle and low dynamic concentration of Fe2+for ROS produc-tion.Herein,we present a three-dimensional(3D)macroscale co-catalyst functionalized with molybde-num disulfide(MoS2)to achieve ultra-efficient Fe2+regeneration(equilibrium Fe2+ratio of 82.4％)and remarkable stability(more than 20 cycles)via a circulating flow-through process.Unlike the conven-tional batch-type reactor,experiments and computational fluid dynamics simulations demonstrate that the optimal utilization of the 3D active area under the flow-through mode,initiated by the convection-enhanced mass/charge transfer for Fe2+reduction and then strengthened by MoS2-induced flow rotation for sufficient reactant mixing,is crucial for oxidant activation and subsequent ROS generation.Strikingly,the flow-through co-catalytic system with superwetting capabilities can even tackle the intricate oily wastewater stabilized by different surfactants without the loss of pollutant degradation efficiency.Our findings highlight an innovative co-catalyst system design to expand the applicability of AOPs based technology,especially in large-scale complex wastewater treatment.
查看更多>>摘要：Photocatalysis offers a sustainable means for the oxidative removal of low concentrations of NOx(NO,NO2,N2O,N2O5,etc.)from the atmosphere.Layered double hydroxides(LDHs)are promising candidate photocatalysts owing to their unique layered and tunable chemical structures and abundant surface hydroxide(OH-)moieties,which are hydroxyl radical(·OH)precursors.However,the practical applica-tions of LDHs are limited by their poor charge-separation ability and insufficient active sites.Herein,we developed a facile N2H4-driven etching approach to introduce dual Ni2+and OH-vacancies(Niv and OHV,respectively)into NiFe-LDH nanosheets(hereafter referred to as NiFe-LDH-et)to facilitate improved charge-carrier separation and active Lewis acidic site(Fe3+and Ni2+exposed at OHV)formation.In contrast to inert pristine LDH,NiFe-LDH-et actively removed NO under visible-light illumination.Specifically,Ni76Fe24-LDH-et etched with 1.50 mmol·L-1 N2H4 solution removed 32.8％of the NO in con-tinuously flowing air(NO feed concentration:～500 parts per billion(ppb))under visible-light illumina-tion,thereby outperforming most reported catalysts.Experimental and theoretical data revealed that the dual vacancies promoted the production of reactive oxygen species(O2·-and·OH)and the adsorption of NO on the LDH.In situ spectroscopy demonstrated that NO was preferentially adsorbed at Lewis acidic sites,particularly exposed Fe3+sites,converted into NO+,and subsequently oxidized to NO3-without the notable formation of the more toxic intermediate NO2,thereby alleviating risks associated with its production and emission.
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