Carbon-based air cathodes offer low cost,high electrical conductivity,and structural tunability.However,they suffer from limited catalytic activity and inefficient gas transport,and they typically rely on noble metal ...Carbon-based air cathodes offer low cost,high electrical conductivity,and structural tunability.However,they suffer from limited catalytic activity and inefficient gas transport,and they typically rely on noble metal additives or complex multilayer configurations.To tackle these issues,this study devised a self-activated integrated carbon-based air cathode.By integrating in situ catalytic site construction with structural optimization,the strategy not only induces the formation of oxygen functional groups(─C─OH,─C═O,─COOH),hierarchical pores,and uniformly distributed active sites,but also establishes a favorable electronic and mass-transport environment.Furthermore,the roll-pressing-based integrated design streamlines electrode construction,reinforces interfacial bonding,and significantly enhances mechanical stability.Density functional theory(DFT)calculations show that oxygen functional groups initiate hydrogen bonding interaction and promote charge enrichment,which improves the activity of the cathode and facilitates intermediate adsorption/desorption in oxygen reduction and evolution reactions processes.As a result,the integrated air cathode-based rechargeable zinc-air batteries(RZABs)achieve a high specific capacity of 811 mAh g^(-1).It also performs well in quasi-solid-state RZABs and silicon-air batteries systems across a wide temperature range,demonstrating strong adaptability and application potential.This study provides a scalable and cost-effective design strategy for high-performance carbon-based air cathodes,offering new insights into advancing durable and practical metal-air energy systems.展开更多
Microorganisms constitute an essential component in the indoor environment,which is closely related to hu-man health.However,there is limited evidence regarding the associations between indoor airborne microbiome and ...Microorganisms constitute an essential component in the indoor environment,which is closely related to hu-man health.However,there is limited evidence regarding the associations between indoor airborne microbiome and systemic inflammation,as well as whether this association is modified by indoor particulate matter and the underlying mechanisms.In this prospective repeated-measure study among 66 participants,indoor airborne mi-crobiome was characterized using amplicon sequencing and qPCR.Indoor fine particulate matter(PM_(2.5))and inhalable particulate matter(PM10)were measured.Systemic inflammatory biomarkers were assessed,including white blood cell(WBC),neutrophil(NEUT),monocyte,eosinophil counts,and their proportions.Targeted serum amino acid metabolomics were conducted to explore the underlying mechanisms.Linear mixed-effect models re-vealed that bacterial and fungal Simpson diversity were significantly associated with decreased WBC and NEUT.For example,for each interquartile range increase in the bacterial Simpson diversity,WBC and NEUT changed by-4.53%(95%CI:-8.25%,-0.66%)and-5.95%(95%CI:-11.3%,-0.27%),respectively.Notably,increased inflammatory risks of airborne microbial exposure were observed when indoor PM_(2.5) and PM10 levels were below the WHO air quality guidelines.Mediation analyses indicated that dopamine metabolism partially mediated the anti-inflammatory effects of fungal diversity exposure.Overall,our study indicated protection from a diverse indoor microbial environment on cardiovascular health and proposed an underlying mechanism through amino acid metabolism.Additionally,health risks associated with microbial exposure deserve more attention in con-texts of low indoor particulate matter pollution.Further research is necessary to fully disentangle the complex relationships between indoor microbiome,air pollutants,and human health.展开更多
The issue of resistance reduction through hull ventilation is of particular interest in contemporary research.This paper presents multiphase computational fluid dynamics(CFD)simulations with 2-DOF motion of a planing ...The issue of resistance reduction through hull ventilation is of particular interest in contemporary research.This paper presents multiphase computational fluid dynamics(CFD)simulations with 2-DOF motion of a planing hull.The original hull was modified by introducing a step to allow air ventilation.Following an assessment of the hull performance,a simulation campaign in calm water was conducted to characterize the hull at various forward speeds and air insufflation rates for a defined single step geometry.Geometric analysis of the air layer thickness beneath the hull for each simulated condition was performed using a novel method for visualizing local air thickness.Additionally,two new parameters were introduced to understand the influence of spray rails on the air volume beneath the hull and to indicate the primary direction of ventilated air escape.A validation campaign and an assessment of uncertainty of the simulation has been conducted.The features offered by the CFD methodology include the evaluation of the air layer thickness as a function of hull velocity and injection flow rate and the air volume distribution beneath the hull.The air injection velocity can be adjusted across various operating conditions,thereby preventing performance or efficiency loss during navigation.Based on these findings,the study highlights the benefits of air insufflation in reducing hull resistance for high-speed planing vessels.This work lays a robust foundation for future research and new promising topics,as the exploration of air insufflation continues to be a topic of contemporary interest within naval architecture and hydrodynamics.展开更多
Ceramic cells promise ideal energy conversion and storage devices,making the development of efficient and robust air electrodes crucial for their application.In this study,a Ba_(0.4)Sr_(0.5)Cs_(0.1)Co_(0.7)Fe_(0.2)Nb_...Ceramic cells promise ideal energy conversion and storage devices,making the development of efficient and robust air electrodes crucial for their application.In this study,a Ba_(0.4)Sr_(0.5)Cs_(0.1)Co_(0.7)Fe_(0.2)Nb_(0.1)O_(3−δ)(BSCCFN)air electrode,based on Ba_(0.5)Sr_(0.5)Co_(0.8)Fe_(0.2)O_(3−δ)(BSCF),is designed using a perovskite A-B-site ionic Lewis acid strength(ISA)polarization distribution strategy and is successfully applied in both oxygen-ion conducting solid oxide fuel cells(O-SOFCs)and proton-conducting reversible protonic ceramic cells(R-PCCs).When BSCCFN is used as the air electrode in O-SOFCs,a peak power density(PPD)of 1.45 W cm^(−2)is achieved at 650°C,whereas in R-PCCs,a PPD of 1.13 W cm^(−2)and a current density of−1.8 A cm^(−2)at 1.3 V are achieved at the same temperature and show stable reversibility over 100 h.Experimental measurements and theoretical calculations demonstrate that low-ISA Cs+doping accelerates the reaction kinetics of both oxygen ions and protons,while high-ISA Nb^(5+)doping enhances electrode stability.The synergistic effect of Cs^(+)and Nb^(5+)co-doping in the BSCCFN electrode lies in the ISA polarization distribution,which weakens the Co/Fe–O bond covalency,thereby promoting oxygen vacancy formation and facilitating the conduction of oxygen ions and protons.展开更多
Perception of air pollution is subjective and context-dependent.Previous studies exploring the association between measured air pollution and perceived air quality mainly focused on air pollution levels measured in th...Perception of air pollution is subjective and context-dependent.Previous studies exploring the association between measured air pollution and perceived air quality mainly focused on air pollution levels measured in the residence-based(RB)or regional context,overlooking the mobility-based(MB)context in which people are exposed to air pollution.This study measures air pollution levels in MB,RB,and regional contexts and examines their relationships with perceived air quality across different neighborhoods and gender sub-groups of Hong Kong,China to investigate how people perceive air quality.The results indicate that particulate matter 2.5(PM_(2.5))measured in RB and the regional context significantly contributes to people’s perceived air quality compared to MB PM_(2.5).Individuals in Central and Western district of Hong Kong rely on RB,regional and MB PM_(2.5) to assess air pollution.In Sham Shui Po,RB PM_(2.5) exhibits the highest influence on people’s perceived air quality,followed by regional PM_(2.5).Women’s perceived air quality is strongly related to their RB PM_(2.5) exposure,while men’s perceived air quality is associated with both RB PM_(2.5) and regional PM_(2.5) levels.We conclude that neighborhood effects and mobility levels are the two most important factors influencing the association between meas-ured air pollution and perceived air quality.We reveal that the neighborhood effect averaging problem(NEAP)influences the associ-ation between perceived air quality and measured air pollution levels in a way that differs from health outcome-related studies.Effect-ive measures are needed to improve the public’s awareness of air pollution,and scientific control should be implemented to reduce pub-lic exposure.展开更多
Unmanned Aircraft Systems(UASs) have advanced technologically and surged exponentially over recent years. Currently, due to safety concerns, most civil operations of UAS are conducted in low-level uncontrolled area or...Unmanned Aircraft Systems(UASs) have advanced technologically and surged exponentially over recent years. Currently, due to safety concerns, most civil operations of UAS are conducted in low-level uncontrolled area or in segregated controlled airspace. As the industry progresses, both operational and technological capabilities have matured to the point where UASs are expected to gain greater freedom of access to both controlled and uncontrolled airspace. Extensive technical and regulatory surveys have been conducted to enable the expanded operations. However, most surveys are derived from the perspective of UAS own operating mechanism and barely consider interactions of their non-segregated activities with the Air Traffic Management(ATM) system. Hence, to fill the gap, this paper presents a survey conducted from the perspective of Air Navigation Service Provider(ANSP), which serves to accommodate these new entrants to the overall national airspace while continuing flight safety and efficiency. The primary objectives of this paper are to:(A) describe what typical ANSP-supplied UAS Traffic Management(UTM) architecture is required to facilitate all types of civil UAS operations;(B) identify three major ANSP considerations on how UAS can be accommodated safely in civil airspace;(C) outline future directions and challenges related with UAS operations for the ANSP.展开更多
This paper presents a thermophysical study approach for a pure environmental control system(ECS),incorporating the geometric dimensions of heat exchangers,ram air duct,and air cycle machine(ACM)blades of the Sabreline...This paper presents a thermophysical study approach for a pure environmental control system(ECS),incorporating the geometric dimensions of heat exchangers,ram air duct,and air cycle machine(ACM)blades of the Sabreliner’s environmental control system.Real flight scenarios are simulated by considering flight input variables such as altitude,aircraft speed,compression ratio of the air cycle machine,and the mass flow rate of bleed air.The study evaluates the coefficient of performance(COP)of the environmental control system,the heat exchanger efficiencies,and the work distribution of the air cycle machine based on five flight scenarios,with a particular focus on considering the effects of humidity on environmental control system performance.The results demonstrate that at cruising altitude(11,000 m),air humidity conditions allow an increase in the COP of around 9.28%compared to dry conditions.Conversely,on land,humidity conditions reduce the performance by 4.26%compared to dry conditions.It was also found that the effects of humidity at high aircraft speeds become negligible.In general terms,the humidity conditions in the air proved to have positive effects on the environmental control system’s performance but negative effects on the heat exchanger efficiencies,reducing them by 0.22%.Additionally,land conditions reflect significant improvements in performance when the compression ratio of the air cycle machine is varied.Furthermore,in the work distribution of the air cycle machine,humidity conditions were demonstrated to consume 2.91%less work fromthe turbine compared to dry conditions.展开更多
Regional turbofan aircraft,which are used for medium-short distances,have a heightened risk of high-altitude Wake Vortices(VV)because of their tail-mounted engines and high horizontal tail configurations.For some regi...Regional turbofan aircraft,which are used for medium-short distances,have a heightened risk of high-altitude Wake Vortices(VV)because of their tail-mounted engines and high horizontal tail configurations.For some regional medium-short-range turbofan aircraft,this threat is higher than that for conventionally designed aircraft.To analyze the flight safety of turbofan aircraft during cruise,this study developed a model to assess wake vortex encounters based on evolutionary high-altitude wake flow patterns.First,the high-altitude wake vortex aircraft dissipation patterns were analyzed by combining Quick Access Recorder(QAR)flight data with the wake vortex evolution model.Then,to consider the uniqueness of the medium-short-range turbofan aircraft,the severity of the wake vortex encounters was simulated using an induced roll moment coefficient.The proposed high-altitude wake vortex encounter model was able to identify and assess the highaltitude wake vortex changes,the bearing moments at different altitudes,and the atmospheric pressure conditions.Using the latest wake separation standards from the International Civil Aviation Organization(ICAO),acceptable safety wake intervals for follower aircraft in different scenarios were determined for the safety assessment.The results indicate that compared to mid and low altitudes,the high-altitude aircraft wake vortex dissipation rate is faster,the ultimate bearing moment is weaker,and the roll moment coefficient is higher,which confirm that there is elevated wake vortex encounter severity for regional turbofan aircraft.As safety is found to deteriorate when encountering wake vortices at altitudes higher than 8 km,new medium-short-range turbofan regional aircraft require higher safety margins than the latest wake separation standards.展开更多
This study investigates the relationships between exposures to ambient air pollution—specifically particulate matter 2.5 (PM_(2.5)) and its metabolites—and the risk of depression.Nonlinear and linear regression,Baye...This study investigates the relationships between exposures to ambient air pollution—specifically particulate matter 2.5 (PM_(2.5)) and its metabolites—and the risk of depression.Nonlinear and linear regression,Bayesian kernel machine regression,and toxicogenomic analysis were key approaches.PM_(2.5)exposure was positively associated with the risk of developing depression,whereas phenylglyoxylic acid exposure was negatively associated with depression risk.We found a significant overall relationship between ambient air pollution and depression,particularly at the 55th and 60th percentiles.Although statistical significance was not reached at the 65th percentile,there was a noticeable upward trend,indicating a potential association.Interestingly,no significant connection was found between a combination of metabolites from ambient air pollution and depression.PM_(2.5)and phenylglyoxylic acid emerged as the most influential compounds in the models,respectively.PM_(2.5)exposure altered the expression of 42 specific targets associated with depression,especially POMC,SCL6A4,IL6,and SOD2.The study identified specific pathways related to insulin secretion,energy metabolism,blood circulation,tube diameter,and maintenance of blood vessel diameter,as well as key molecular mechanisms involving hsa-miR-124-3p,hsa-miR-155-5p,hsa-miR-16-5p,and SP1.These mechanisms were found to underlie the etiology of depression associated with PM_(2.5)exposure.In conclusions,PM_(2.5)and phenylglyoxylic acid were found to be associated with depression.Further work is needed to gain insight into the molecular mechanisms by which these chemicals affect depression,especially pathways related to insulin secretion and blood circulation.展开更多
The lined rock cavern(LRC)compressed air energy storage(CAES)system is currently regarded as one of the most promising methods for large-scale energy storage.However,the safety of LRC under high internal pressure has ...The lined rock cavern(LRC)compressed air energy storage(CAES)system is currently regarded as one of the most promising methods for large-scale energy storage.However,the safety of LRC under high internal pressure has emerged as a critical issue that restricts their development.While scholars have focused on the safety of LRC under multiphysics field coupling,few have noticed the inevitable damage sustained by the primary load-bearing components—the surrounding rock and concrete lining—under high internal pressure,compromising their strength and permeation resistance.This study investigates the impact of damage to the surrounding rock and lining concrete on the stability and airtightness of the CAES cavern.First,a damagepermeability evolution model was established by analyzing cyclic loading and unloading test data on concrete samples.Then,a thermo-hydro-mechanical damage(THM-D)coupling model for the CAES cavern was developed and validated against operational data from the Huntorf plant.The coupling responses of both the surrounding rock and lining were compared and analyzed under three different schemes of the first charging and discharging operation.The results revealed the correlation between the air temperature in the cavern and the injection rate and the uneven damage evolution of the surrounding rock and lining caused by the geostress distribution coupled with the heat transfer process.Through the analysis,a higher air injection rate causes more lining damage and air leakage,posing greater risks to engineering safety and airtightness.However,the reduction of inflation time will weaken this effect to some extent.These findings offer valuable insights into the design,construction,and safe operation of LRC compressed air energy storage systems.展开更多
Aiming at reducing the dust pollution during the tunneling process and improving the application efficiency of air curtain dust prevention technology,according to the changes of radial jet velocity(v_(r)),axial extrac...Aiming at reducing the dust pollution during the tunneling process and improving the application efficiency of air curtain dust prevention technology,according to the changes of radial jet velocity(v_(r)),axial extraction velocity(v_(e))and extraction distance(L)in the formation process of air curtain,the numerical simulation method was used to analyze the rules of airflow structure evolution and the diffusion characteristics of dust particles in fully mechanized excavation tunnel.The results indicate that as v_(r) and v_(e) increase,the migration path of the wall jet of the air curtain changes into an axial direction;as L decreases,the migration distance increases accordingly.These phenomena make the airflow distribution in the working face tends to be uniform.The dust diffusion distance reduces as well,wherein,the range of the discrete area of dust particles decreases sharply,until all dust particles are concentrated in the accumulation area.On this basis,the v_(r),v_(e) and L were optimized and applied in the 63_(up) 08 fully mechanized working face.By the application of the optimal parameters,the average dust removal efficiency at the driver’s position increased by 71%.The dust concentration was reduced and the working environment had been improved effectively.展开更多
High-energy-density lithium(Li)–air cells have been considered a promising energy-storage system,but the liquid electrolyte-related safety and side-reaction problems seriously hinder their development.To address thes...High-energy-density lithium(Li)–air cells have been considered a promising energy-storage system,but the liquid electrolyte-related safety and side-reaction problems seriously hinder their development.To address these above issues,solid-state Li–air batteries have been widely developed.However,many commonly-used solid electrolytes generally face huge interface impedance inLi–air cells and also showpoor stability towards ambient air/Li electrodes.Herein,we fabricate a differentiating surface-regulated ceramic-based composite electrolyte(DSCCE)by constructing disparately LiI-containing polymethyl methacrylate(PMMA)coating and Poly(vinylidene fluoride-co-hexafluoropropylene)(PVDF-HFP)layer on both sides of Li_(1.5)Al_(0.5)Ge_(1.5)(PO_(4))_(3)(LAGP).The cathode-friendly LiI/PMMA layer displays excellent stability towards superoxide intermediates and also greatly reduces the decomposition voltage of discharge products in Li–air system.Additionally,the anode-friendly PVDF-HFP coating shows low-resistance properties towards anodes.Moreover,Li dendrite/passivation derived from liquid electrolyte-induced side reactions and air/I-attacking can be obviously suppressed by the uniformand compact composite framework.As a result,the DSCCE-based Li–air batteries possess high capacity/low voltage polarization(11,836mAh g^(-1)/1.45Vunder 500mAg^(-1)),good rate performance(capacity ratio under 1000mAg^(-1)/250mAg^(-1) is 68.2%)and longterm stable cell operation(~300 cycles at 750 mA g^(-1) with 750 mAh g^(-1))in ambient air.展开更多
Lithium-air batteries(LABs)are regarded as a next-generation energy storage option due to their relatively high energy density.The cyclic stability and lifespan of LABs are mainly influenced by the formation and decom...Lithium-air batteries(LABs)are regarded as a next-generation energy storage option due to their relatively high energy density.The cyclic stability and lifespan of LABs are mainly influenced by the formation and decomposition of lithium-based oxides at the air cathode,which not only lead to a low cathode catalytic efficiency but also restrict the electrochemical reversibility and cause side reaction problems.Carbon materials are considered key to solving these problems due to their conductivity,functional flexibility,and adjustable pore structure.This paper considers the research progress on carbon materials as air cathode catalytic materials for LABs,focusing on their structural characteristics,electrochemical behavior,and reaction mechanisms.Besides being used as air cathodes,carbon materials also show potential for being used as protective layers for metal anodes or as anode materials for LABs.展开更多
African Aviation continues to fall short of serving the demands of the fast-growing African population. For major air transport in and out of the African continent, African travellers rely mainly on non-African Airlin...African Aviation continues to fall short of serving the demands of the fast-growing African population. For major air transport in and out of the African continent, African travellers rely mainly on non-African Airlines. There is, however, one successful airline on the continent at the writing of this paper: Ethiopian Airlines and the Ethiopian Aviation Group. Why are no further successful airlines possible on a continent of 1.4 billion people (25% of the world’s population) and only a 2%-share of global air transport? At the introduction of SAATM, which is anticipated as the start of the domestic African aviation boom, most African countries seem unprepared to build a success story like Ethiopia. Transportation infrastructure in sub-Saharan Africa does not start with roads and rail but with runways and airlines. This research investigates the basic requirements needed to equip Africa with a competitive aviation industry that would contribute some 5% to the continent’s GDP and create hundreds of thousands of workplaces. Interviews with African SAATM leaders signal a slowdown in the effort to succeed. The research is also concerned about the lack of inclusion in the implementation of a NetZero CO2 emission scheme in Africa.展开更多
Flapping-Wing Air Vehicles(FWAVs)have been developed to pursue the efficient,agile,and quiet flight of flying animals.However,unlike lightweight FWAVs capable of vertical takeoff,relatively heavy FWAVs face challenges...Flapping-Wing Air Vehicles(FWAVs)have been developed to pursue the efficient,agile,and quiet flight of flying animals.However,unlike lightweight FWAVs capable of vertical takeoff,relatively heavy FWAVs face challenges in self-takeoff,which refers to taking off without both external device and energy input.In this study,a cliff-drop method is implemented for an independent takeoff of a heavy FWAV,relying solely on gravity.In the takeoff process using the cliff-drop method,the FWAV moves on the ground to a cliff edge using a wheel-driving motor and then descends from the cliff to achieve the necessary speed for flight.To demonstrate the cliff-drop method,the KAIST Robotic Hawk(KRoHawk)with a mass of 740 g and a wingspan of 120 cm is developed.The takeoff tests demonstrate that the KRoHawk,significantly heavier than the vertical-takeoff capable FWAVs,can successfully take off using the gravity-assisted takeoff method.The scalability of cliff-drop method is analyzed through simulations.When drop constraints are absent,the wheel-driving motor mass fraction for cliff-drop method remains negligible even as the vehicle's weight increases.When drop constraints are set to 4 m,FWAVs heavier than KRoHawk,weighing up to 4.4 kg,can perform the cliff-drop takeoffs with a wheel-driving motor mass fraction of less than 8%.展开更多
Clean air is fundamental to human health.Approximately 99%of the global population has been exposed to concentrations higher than the World Health Organization’s recommendations.Moreover,adverse health effects have b...Clean air is fundamental to human health.Approximately 99%of the global population has been exposed to concentrations higher than the World Health Organization’s recommendations.Moreover,adverse health effects have been observed at much lower pollution levels than previously studied.China has experienced periods of severe air pollution over the past few decades.To improve air quality and safeguard public health,the government has implemented several progressively tightened policies.Emission control policies were first proposed in 2005.展开更多
The Textile Technology Centre is the pride of Heberlein.State-of-the-art equipment and a team of top experts guarantee the highest standards of support for customers.Heberlein is the leading provider of air interlacin...The Textile Technology Centre is the pride of Heberlein.State-of-the-art equipment and a team of top experts guarantee the highest standards of support for customers.Heberlein is the leading provider of air interlacing and air texturing jets for synthetic continuous filament yarns and its clients enjoy added value in the form of practical help and guidance on textile processes and economic issues,with a special focus on filament yarn applications.展开更多
Shaoxing Shuifu Reeds is professional on producing all kinds of Air Jet Reeds and Flat Reeds,which has an annual output of 90,000 meters air-jet reeds,300,000,000 pcs of profile dents and 60,000 meters of Flat Reeds,W...Shaoxing Shuifu Reeds is professional on producing all kinds of Air Jet Reeds and Flat Reeds,which has an annual output of 90,000 meters air-jet reeds,300,000,000 pcs of profile dents and 60,000 meters of Flat Reeds,Which has been honored with China Air Jet Profile Reeds Research Center by China Textile Machinery Association in 2015.In order to reach the demands of high quality fabric and industrial textile products,the yarn is developing to high count,multicolor,various fibers,and the fabric is developing to high count,high density,environment protection.So we have researched out high density,multicolor,multinozzle,double energy saving type profile reeds to let you choose.展开更多
Direct air capture(DAC)is a negative carbon emission technology that faces challenges in scalability and practical deployment due to its exorbitant costs.Hou et al.(2017)integrated DAC technology with fertilization.A ...Direct air capture(DAC)is a negative carbon emission technology that faces challenges in scalability and practical deployment due to its exorbitant costs.Hou et al.(2017)integrated DAC technology with fertilization.A multi-bed desorption system driven by water provides a competitive and sustainable carbon source for indoor agriculture.展开更多
基金funded by the National Nature Science Foundation of China(62264006,62574102)“Thousand Talents Program”of Yunnan Province for Young Talents,Innovative Research Teams(in Science and Technology)in the University of Yunnan Province(IRTSTYN),XingDian Talent Support Program for Young Talents,and Frontier Research Team of Kunming University 2023,The Basic Research Project of Yunnan Province(Nos.202201AU070022)+2 种基金Kunming University Talent Introduction Fund(Nos.YJL20024)Yunnan Province Education Department Scientific Research Fund Project(Nos.2024Y759)Undergraduate Innovation and Entrepreneurship Training Program Project of Yunnan Provincial(202411393005)。
文摘Carbon-based air cathodes offer low cost,high electrical conductivity,and structural tunability.However,they suffer from limited catalytic activity and inefficient gas transport,and they typically rely on noble metal additives or complex multilayer configurations.To tackle these issues,this study devised a self-activated integrated carbon-based air cathode.By integrating in situ catalytic site construction with structural optimization,the strategy not only induces the formation of oxygen functional groups(─C─OH,─C═O,─COOH),hierarchical pores,and uniformly distributed active sites,but also establishes a favorable electronic and mass-transport environment.Furthermore,the roll-pressing-based integrated design streamlines electrode construction,reinforces interfacial bonding,and significantly enhances mechanical stability.Density functional theory(DFT)calculations show that oxygen functional groups initiate hydrogen bonding interaction and promote charge enrichment,which improves the activity of the cathode and facilitates intermediate adsorption/desorption in oxygen reduction and evolution reactions processes.As a result,the integrated air cathode-based rechargeable zinc-air batteries(RZABs)achieve a high specific capacity of 811 mAh g^(-1).It also performs well in quasi-solid-state RZABs and silicon-air batteries systems across a wide temperature range,demonstrating strong adaptability and application potential.This study provides a scalable and cost-effective design strategy for high-performance carbon-based air cathodes,offering new insights into advancing durable and practical metal-air energy systems.
基金supported by the National Key Research and Development Program of China(No.2022YFC3702704)the National Natural Science Foundation of China(Nos.22376005,22076006 and 82073506).
文摘Microorganisms constitute an essential component in the indoor environment,which is closely related to hu-man health.However,there is limited evidence regarding the associations between indoor airborne microbiome and systemic inflammation,as well as whether this association is modified by indoor particulate matter and the underlying mechanisms.In this prospective repeated-measure study among 66 participants,indoor airborne mi-crobiome was characterized using amplicon sequencing and qPCR.Indoor fine particulate matter(PM_(2.5))and inhalable particulate matter(PM10)were measured.Systemic inflammatory biomarkers were assessed,including white blood cell(WBC),neutrophil(NEUT),monocyte,eosinophil counts,and their proportions.Targeted serum amino acid metabolomics were conducted to explore the underlying mechanisms.Linear mixed-effect models re-vealed that bacterial and fungal Simpson diversity were significantly associated with decreased WBC and NEUT.For example,for each interquartile range increase in the bacterial Simpson diversity,WBC and NEUT changed by-4.53%(95%CI:-8.25%,-0.66%)and-5.95%(95%CI:-11.3%,-0.27%),respectively.Notably,increased inflammatory risks of airborne microbial exposure were observed when indoor PM_(2.5) and PM10 levels were below the WHO air quality guidelines.Mediation analyses indicated that dopamine metabolism partially mediated the anti-inflammatory effects of fungal diversity exposure.Overall,our study indicated protection from a diverse indoor microbial environment on cardiovascular health and proposed an underlying mechanism through amino acid metabolism.Additionally,health risks associated with microbial exposure deserve more attention in con-texts of low indoor particulate matter pollution.Further research is necessary to fully disentangle the complex relationships between indoor microbiome,air pollutants,and human health.
基金supported by European Union funding(PON“Ricerca e Innovazione”2014‒2020).
文摘The issue of resistance reduction through hull ventilation is of particular interest in contemporary research.This paper presents multiphase computational fluid dynamics(CFD)simulations with 2-DOF motion of a planing hull.The original hull was modified by introducing a step to allow air ventilation.Following an assessment of the hull performance,a simulation campaign in calm water was conducted to characterize the hull at various forward speeds and air insufflation rates for a defined single step geometry.Geometric analysis of the air layer thickness beneath the hull for each simulated condition was performed using a novel method for visualizing local air thickness.Additionally,two new parameters were introduced to understand the influence of spray rails on the air volume beneath the hull and to indicate the primary direction of ventilated air escape.A validation campaign and an assessment of uncertainty of the simulation has been conducted.The features offered by the CFD methodology include the evaluation of the air layer thickness as a function of hull velocity and injection flow rate and the air volume distribution beneath the hull.The air injection velocity can be adjusted across various operating conditions,thereby preventing performance or efficiency loss during navigation.Based on these findings,the study highlights the benefits of air insufflation in reducing hull resistance for high-speed planing vessels.This work lays a robust foundation for future research and new promising topics,as the exploration of air insufflation continues to be a topic of contemporary interest within naval architecture and hydrodynamics.
基金funding from the National Natural Science Foundation of China(Award 91745203)supplemented by Central Universities'Basic Research Funds.We gratefully acknowledge the National Synchrotron Radiation Laboratory(NSRL,Hefei,China)for providing MCD-A and MCD-B beamlines for Soft XAS characterization.The authors are grateful to the Instrument and equipment sharing platform,College of Physics,Jilin University,for providing technical assistance in HT-XRD measurements.
文摘Ceramic cells promise ideal energy conversion and storage devices,making the development of efficient and robust air electrodes crucial for their application.In this study,a Ba_(0.4)Sr_(0.5)Cs_(0.1)Co_(0.7)Fe_(0.2)Nb_(0.1)O_(3−δ)(BSCCFN)air electrode,based on Ba_(0.5)Sr_(0.5)Co_(0.8)Fe_(0.2)O_(3−δ)(BSCF),is designed using a perovskite A-B-site ionic Lewis acid strength(ISA)polarization distribution strategy and is successfully applied in both oxygen-ion conducting solid oxide fuel cells(O-SOFCs)and proton-conducting reversible protonic ceramic cells(R-PCCs).When BSCCFN is used as the air electrode in O-SOFCs,a peak power density(PPD)of 1.45 W cm^(−2)is achieved at 650°C,whereas in R-PCCs,a PPD of 1.13 W cm^(−2)and a current density of−1.8 A cm^(−2)at 1.3 V are achieved at the same temperature and show stable reversibility over 100 h.Experimental measurements and theoretical calculations demonstrate that low-ISA Cs+doping accelerates the reaction kinetics of both oxygen ions and protons,while high-ISA Nb^(5+)doping enhances electrode stability.The synergistic effect of Cs^(+)and Nb^(5+)co-doping in the BSCCFN electrode lies in the ISA polarization distribution,which weakens the Co/Fe–O bond covalency,thereby promoting oxygen vacancy formation and facilitating the conduction of oxygen ions and protons.
基金Under the auspices of the Hong Kong Research Grants Council(No.14605920,14606922,14603724,C4023-20GF,8601219,8601242,3110151)a Grant from the Research Committee on Research Sustainability of Major Research Grants Council Funding Schemes of the Chinese University of Hong Kong(CUHK,No.3133235)the Vice-Chancellor’s One-off Discretionary Fund of CUHK(No.4930787)。
文摘Perception of air pollution is subjective and context-dependent.Previous studies exploring the association between measured air pollution and perceived air quality mainly focused on air pollution levels measured in the residence-based(RB)or regional context,overlooking the mobility-based(MB)context in which people are exposed to air pollution.This study measures air pollution levels in MB,RB,and regional contexts and examines their relationships with perceived air quality across different neighborhoods and gender sub-groups of Hong Kong,China to investigate how people perceive air quality.The results indicate that particulate matter 2.5(PM_(2.5))measured in RB and the regional context significantly contributes to people’s perceived air quality compared to MB PM_(2.5).Individuals in Central and Western district of Hong Kong rely on RB,regional and MB PM_(2.5) to assess air pollution.In Sham Shui Po,RB PM_(2.5) exhibits the highest influence on people’s perceived air quality,followed by regional PM_(2.5).Women’s perceived air quality is strongly related to their RB PM_(2.5) exposure,while men’s perceived air quality is associated with both RB PM_(2.5) and regional PM_(2.5) levels.We conclude that neighborhood effects and mobility levels are the two most important factors influencing the association between meas-ured air pollution and perceived air quality.We reveal that the neighborhood effect averaging problem(NEAP)influences the associ-ation between perceived air quality and measured air pollution levels in a way that differs from health outcome-related studies.Effect-ive measures are needed to improve the public’s awareness of air pollution,and scientific control should be implemented to reduce pub-lic exposure.
基金co-supported by the Outstanding Youth Fund of the National Natural Science Foundation of China (No. 61822102)the MIIT Technological Base Program (No. JSZL2016601B003)the National Key Research and Development Program (No. 2018YFB0505105)。
文摘Unmanned Aircraft Systems(UASs) have advanced technologically and surged exponentially over recent years. Currently, due to safety concerns, most civil operations of UAS are conducted in low-level uncontrolled area or in segregated controlled airspace. As the industry progresses, both operational and technological capabilities have matured to the point where UASs are expected to gain greater freedom of access to both controlled and uncontrolled airspace. Extensive technical and regulatory surveys have been conducted to enable the expanded operations. However, most surveys are derived from the perspective of UAS own operating mechanism and barely consider interactions of their non-segregated activities with the Air Traffic Management(ATM) system. Hence, to fill the gap, this paper presents a survey conducted from the perspective of Air Navigation Service Provider(ANSP), which serves to accommodate these new entrants to the overall national airspace while continuing flight safety and efficiency. The primary objectives of this paper are to:(A) describe what typical ANSP-supplied UAS Traffic Management(UTM) architecture is required to facilitate all types of civil UAS operations;(B) identify three major ANSP considerations on how UAS can be accommodated safely in civil airspace;(C) outline future directions and challenges related with UAS operations for the ANSP.
文摘This paper presents a thermophysical study approach for a pure environmental control system(ECS),incorporating the geometric dimensions of heat exchangers,ram air duct,and air cycle machine(ACM)blades of the Sabreliner’s environmental control system.Real flight scenarios are simulated by considering flight input variables such as altitude,aircraft speed,compression ratio of the air cycle machine,and the mass flow rate of bleed air.The study evaluates the coefficient of performance(COP)of the environmental control system,the heat exchanger efficiencies,and the work distribution of the air cycle machine based on five flight scenarios,with a particular focus on considering the effects of humidity on environmental control system performance.The results demonstrate that at cruising altitude(11,000 m),air humidity conditions allow an increase in the COP of around 9.28%compared to dry conditions.Conversely,on land,humidity conditions reduce the performance by 4.26%compared to dry conditions.It was also found that the effects of humidity at high aircraft speeds become negligible.In general terms,the humidity conditions in the air proved to have positive effects on the environmental control system’s performance but negative effects on the heat exchanger efficiencies,reducing them by 0.22%.Additionally,land conditions reflect significant improvements in performance when the compression ratio of the air cycle machine is varied.Furthermore,in the work distribution of the air cycle machine,humidity conditions were demonstrated to consume 2.91%less work fromthe turbine compared to dry conditions.
基金supported by the National Natural Science Foundation of China(Nos.U2333209,U1733203)the National Key R&D Program of China(No.2021YFF0603904)the Civil Aviation Administration of China(No.AQ20200019)。
文摘Regional turbofan aircraft,which are used for medium-short distances,have a heightened risk of high-altitude Wake Vortices(VV)because of their tail-mounted engines and high horizontal tail configurations.For some regional medium-short-range turbofan aircraft,this threat is higher than that for conventionally designed aircraft.To analyze the flight safety of turbofan aircraft during cruise,this study developed a model to assess wake vortex encounters based on evolutionary high-altitude wake flow patterns.First,the high-altitude wake vortex aircraft dissipation patterns were analyzed by combining Quick Access Recorder(QAR)flight data with the wake vortex evolution model.Then,to consider the uniqueness of the medium-short-range turbofan aircraft,the severity of the wake vortex encounters was simulated using an induced roll moment coefficient.The proposed high-altitude wake vortex encounter model was able to identify and assess the highaltitude wake vortex changes,the bearing moments at different altitudes,and the atmospheric pressure conditions.Using the latest wake separation standards from the International Civil Aviation Organization(ICAO),acceptable safety wake intervals for follower aircraft in different scenarios were determined for the safety assessment.The results indicate that compared to mid and low altitudes,the high-altitude aircraft wake vortex dissipation rate is faster,the ultimate bearing moment is weaker,and the roll moment coefficient is higher,which confirm that there is elevated wake vortex encounter severity for regional turbofan aircraft.As safety is found to deteriorate when encountering wake vortices at altitudes higher than 8 km,new medium-short-range turbofan regional aircraft require higher safety margins than the latest wake separation standards.
文摘This study investigates the relationships between exposures to ambient air pollution—specifically particulate matter 2.5 (PM_(2.5)) and its metabolites—and the risk of depression.Nonlinear and linear regression,Bayesian kernel machine regression,and toxicogenomic analysis were key approaches.PM_(2.5)exposure was positively associated with the risk of developing depression,whereas phenylglyoxylic acid exposure was negatively associated with depression risk.We found a significant overall relationship between ambient air pollution and depression,particularly at the 55th and 60th percentiles.Although statistical significance was not reached at the 65th percentile,there was a noticeable upward trend,indicating a potential association.Interestingly,no significant connection was found between a combination of metabolites from ambient air pollution and depression.PM_(2.5)and phenylglyoxylic acid emerged as the most influential compounds in the models,respectively.PM_(2.5)exposure altered the expression of 42 specific targets associated with depression,especially POMC,SCL6A4,IL6,and SOD2.The study identified specific pathways related to insulin secretion,energy metabolism,blood circulation,tube diameter,and maintenance of blood vessel diameter,as well as key molecular mechanisms involving hsa-miR-124-3p,hsa-miR-155-5p,hsa-miR-16-5p,and SP1.These mechanisms were found to underlie the etiology of depression associated with PM_(2.5)exposure.In conclusions,PM_(2.5)and phenylglyoxylic acid were found to be associated with depression.Further work is needed to gain insight into the molecular mechanisms by which these chemicals affect depression,especially pathways related to insulin secretion and blood circulation.
基金National Natural Science Foundation of China,Grant/Award Number:U23B20147Key Research Program of Frontier Sciences,Chinese Academy of Sciences(CAS),Grant/Award Number:ZDBS-LY-DQC022+1 种基金Hubei Provincial Natural Science Foundation of China,Grant/Award Number:2023AFB346Knowledge Innovation Program of Wuhan-Shuguang Project,Grant/Award Number:2023010201020278。
文摘The lined rock cavern(LRC)compressed air energy storage(CAES)system is currently regarded as one of the most promising methods for large-scale energy storage.However,the safety of LRC under high internal pressure has emerged as a critical issue that restricts their development.While scholars have focused on the safety of LRC under multiphysics field coupling,few have noticed the inevitable damage sustained by the primary load-bearing components—the surrounding rock and concrete lining—under high internal pressure,compromising their strength and permeation resistance.This study investigates the impact of damage to the surrounding rock and lining concrete on the stability and airtightness of the CAES cavern.First,a damagepermeability evolution model was established by analyzing cyclic loading and unloading test data on concrete samples.Then,a thermo-hydro-mechanical damage(THM-D)coupling model for the CAES cavern was developed and validated against operational data from the Huntorf plant.The coupling responses of both the surrounding rock and lining were compared and analyzed under three different schemes of the first charging and discharging operation.The results revealed the correlation between the air temperature in the cavern and the injection rate and the uneven damage evolution of the surrounding rock and lining caused by the geostress distribution coupled with the heat transfer process.Through the analysis,a higher air injection rate causes more lining damage and air leakage,posing greater risks to engineering safety and airtightness.However,the reduction of inflation time will weaken this effect to some extent.These findings offer valuable insights into the design,construction,and safe operation of LRC compressed air energy storage systems.
基金financially supported by the Natural Science Foundation of Shandong Province(ZR2020QE124,ZR2023ME031 and ZR2023ME012)Innovation Achievement Cultivation Project of Qingdao University of Technology(CLZ2022-002)National Natural Science Foundation of China(52404222 and 52374209).
文摘Aiming at reducing the dust pollution during the tunneling process and improving the application efficiency of air curtain dust prevention technology,according to the changes of radial jet velocity(v_(r)),axial extraction velocity(v_(e))and extraction distance(L)in the formation process of air curtain,the numerical simulation method was used to analyze the rules of airflow structure evolution and the diffusion characteristics of dust particles in fully mechanized excavation tunnel.The results indicate that as v_(r) and v_(e) increase,the migration path of the wall jet of the air curtain changes into an axial direction;as L decreases,the migration distance increases accordingly.These phenomena make the airflow distribution in the working face tends to be uniform.The dust diffusion distance reduces as well,wherein,the range of the discrete area of dust particles decreases sharply,until all dust particles are concentrated in the accumulation area.On this basis,the v_(r),v_(e) and L were optimized and applied in the 63_(up) 08 fully mechanized working face.By the application of the optimal parameters,the average dust removal efficiency at the driver’s position increased by 71%.The dust concentration was reduced and the working environment had been improved effectively.
基金supported by the National Natural Science Foundation of China(22379074)Young Science and Technology Talent Program of Inner Mongolia Province(NJYT24001)+4 种基金Natural Sciences and Engineering Research Council of Canada(NSERC)GLABAT Solid-State Battery Inc.,China Automotive Battery Research Institute Co.Ltd,Canada Research Chair Program(CRC)Canada Foundation for Innovation(CFI)Ontario Research Fundsupported by the Chinese Scholarship Council.
文摘High-energy-density lithium(Li)–air cells have been considered a promising energy-storage system,but the liquid electrolyte-related safety and side-reaction problems seriously hinder their development.To address these above issues,solid-state Li–air batteries have been widely developed.However,many commonly-used solid electrolytes generally face huge interface impedance inLi–air cells and also showpoor stability towards ambient air/Li electrodes.Herein,we fabricate a differentiating surface-regulated ceramic-based composite electrolyte(DSCCE)by constructing disparately LiI-containing polymethyl methacrylate(PMMA)coating and Poly(vinylidene fluoride-co-hexafluoropropylene)(PVDF-HFP)layer on both sides of Li_(1.5)Al_(0.5)Ge_(1.5)(PO_(4))_(3)(LAGP).The cathode-friendly LiI/PMMA layer displays excellent stability towards superoxide intermediates and also greatly reduces the decomposition voltage of discharge products in Li–air system.Additionally,the anode-friendly PVDF-HFP coating shows low-resistance properties towards anodes.Moreover,Li dendrite/passivation derived from liquid electrolyte-induced side reactions and air/I-attacking can be obviously suppressed by the uniformand compact composite framework.As a result,the DSCCE-based Li–air batteries possess high capacity/low voltage polarization(11,836mAh g^(-1)/1.45Vunder 500mAg^(-1)),good rate performance(capacity ratio under 1000mAg^(-1)/250mAg^(-1) is 68.2%)and longterm stable cell operation(~300 cycles at 750 mA g^(-1) with 750 mAh g^(-1))in ambient air.
文摘Lithium-air batteries(LABs)are regarded as a next-generation energy storage option due to their relatively high energy density.The cyclic stability and lifespan of LABs are mainly influenced by the formation and decomposition of lithium-based oxides at the air cathode,which not only lead to a low cathode catalytic efficiency but also restrict the electrochemical reversibility and cause side reaction problems.Carbon materials are considered key to solving these problems due to their conductivity,functional flexibility,and adjustable pore structure.This paper considers the research progress on carbon materials as air cathode catalytic materials for LABs,focusing on their structural characteristics,electrochemical behavior,and reaction mechanisms.Besides being used as air cathodes,carbon materials also show potential for being used as protective layers for metal anodes or as anode materials for LABs.
文摘African Aviation continues to fall short of serving the demands of the fast-growing African population. For major air transport in and out of the African continent, African travellers rely mainly on non-African Airlines. There is, however, one successful airline on the continent at the writing of this paper: Ethiopian Airlines and the Ethiopian Aviation Group. Why are no further successful airlines possible on a continent of 1.4 billion people (25% of the world’s population) and only a 2%-share of global air transport? At the introduction of SAATM, which is anticipated as the start of the domestic African aviation boom, most African countries seem unprepared to build a success story like Ethiopia. Transportation infrastructure in sub-Saharan Africa does not start with roads and rail but with runways and airlines. This research investigates the basic requirements needed to equip Africa with a competitive aviation industry that would contribute some 5% to the continent’s GDP and create hundreds of thousands of workplaces. Interviews with African SAATM leaders signal a slowdown in the effort to succeed. The research is also concerned about the lack of inclusion in the implementation of a NetZero CO2 emission scheme in Africa.
基金supported by Unmanned Vehicles Core Technology Research and Development Program through the National Research Foundation of Korea(NRF)Unmanned Vehicle Advanced Research Center(UVARC)funded by the Ministry of Science and ICT,the Republic of Korea(2020M3C1C1A01083415).
文摘Flapping-Wing Air Vehicles(FWAVs)have been developed to pursue the efficient,agile,and quiet flight of flying animals.However,unlike lightweight FWAVs capable of vertical takeoff,relatively heavy FWAVs face challenges in self-takeoff,which refers to taking off without both external device and energy input.In this study,a cliff-drop method is implemented for an independent takeoff of a heavy FWAV,relying solely on gravity.In the takeoff process using the cliff-drop method,the FWAV moves on the ground to a cliff edge using a wheel-driving motor and then descends from the cliff to achieve the necessary speed for flight.To demonstrate the cliff-drop method,the KAIST Robotic Hawk(KRoHawk)with a mass of 740 g and a wingspan of 120 cm is developed.The takeoff tests demonstrate that the KRoHawk,significantly heavier than the vertical-takeoff capable FWAVs,can successfully take off using the gravity-assisted takeoff method.The scalability of cliff-drop method is analyzed through simulations.When drop constraints are absent,the wheel-driving motor mass fraction for cliff-drop method remains negligible even as the vehicle's weight increases.When drop constraints are set to 4 m,FWAVs heavier than KRoHawk,weighing up to 4.4 kg,can perform the cliff-drop takeoffs with a wheel-driving motor mass fraction of less than 8%.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFC3702702)National Natural Science Foundation of China(Grant No.82103871).
文摘Clean air is fundamental to human health.Approximately 99%of the global population has been exposed to concentrations higher than the World Health Organization’s recommendations.Moreover,adverse health effects have been observed at much lower pollution levels than previously studied.China has experienced periods of severe air pollution over the past few decades.To improve air quality and safeguard public health,the government has implemented several progressively tightened policies.Emission control policies were first proposed in 2005.
文摘The Textile Technology Centre is the pride of Heberlein.State-of-the-art equipment and a team of top experts guarantee the highest standards of support for customers.Heberlein is the leading provider of air interlacing and air texturing jets for synthetic continuous filament yarns and its clients enjoy added value in the form of practical help and guidance on textile processes and economic issues,with a special focus on filament yarn applications.
文摘Shaoxing Shuifu Reeds is professional on producing all kinds of Air Jet Reeds and Flat Reeds,which has an annual output of 90,000 meters air-jet reeds,300,000,000 pcs of profile dents and 60,000 meters of Flat Reeds,Which has been honored with China Air Jet Profile Reeds Research Center by China Textile Machinery Association in 2015.In order to reach the demands of high quality fabric and industrial textile products,the yarn is developing to high count,multicolor,various fibers,and the fabric is developing to high count,high density,environment protection.So we have researched out high density,multicolor,multinozzle,double energy saving type profile reeds to let you choose.
基金supported by the National Natural Science Foundation of China(No.52276022).
文摘Direct air capture(DAC)is a negative carbon emission technology that faces challenges in scalability and practical deployment due to its exorbitant costs.Hou et al.(2017)integrated DAC technology with fertilization.A multi-bed desorption system driven by water provides a competitive and sustainable carbon source for indoor agriculture.
