With the anticipated growth in air traffic complexity in the coming years,future civil aviation transportation system(CATS)is transforming into a complex cyber–physical–social system,surpassing all previous experien...With the anticipated growth in air traffic complexity in the coming years,future civil aviation transportation system(CATS)is transforming into a complex cyber–physical–social system,surpassing all previous experiences in the history of civil aviation safety management.Therefore,a new safety concept based on a system-of-systems(SoS)perspective is proposed for the next-generation aviation.This article begins by elucidating the complexity of existing aviation risks and emphasizing the necessity for an updated safety concept.It then presents the challenges of current safety management and potential solutions from the new SoS perspective.To address future risks,the concept of SoS safety is introduced with the inspiration of the human immune system in terms of capability,logic,and architecture,which can serve as a guiding framework and methodology for safety engineering in complex large-scale CATS.This concept indicates the transition from“process and outcome-oriented”to“capability-oriented”intelligent safety management.Our research highlights the development directions and potential technological areas that need to be addressed at different stages of SoS safety.The integration of SoS design and operation through rapid iterations enabled by artificial intelligence(AI)will ultimately achieve endogenous SoS safety.展开更多
This study examines a curriculum system developed at the College of Aviation Manufacturing Industry at Nanchang Hangkong University through Industry-Education Integration(I-E Integration).Drawing on engineering educat...This study examines a curriculum system developed at the College of Aviation Manufacturing Industry at Nanchang Hangkong University through Industry-Education Integration(I-E Integration).Drawing on engineering education principles and reforms in the Mechanical Design,Manufacturing,and Automation program,it aligns course design with industry needs,integrates technological advancements,and embeds production processes.The approach restructures modular course content based on aviation manufacturing technologies,implements project-based learning via a university-enterprise"factory-in-school"training base,and adopts an Outcome-Based Education(OBE)system for evaluation and improvement.This replicable model provides practical insights for industry-focused curriculum development.展开更多
With the deployment of ultra-dense low earth orbit(LEO)satellite constellations,LEO satellite access network(LEO-SAN)is envisioned to achieve global Internet coverage.Meanwhile,the civil aviation communications have i...With the deployment of ultra-dense low earth orbit(LEO)satellite constellations,LEO satellite access network(LEO-SAN)is envisioned to achieve global Internet coverage.Meanwhile,the civil aviation communications have increased dramatically,especially for providing airborne Internet services.However,due to dynamic service demands and onboard LEO resources over time and space,it poses huge challenges in satellite-aircraft access and service management in ultra-dense LEO satellite networks(UDLSN).In this paper,we propose a deep reinforcement learning-based approach for ultra-dense LEO satellite-aircraft access and service management.Firstly,we develop an airborne Internet architecture based on UDLSN and design a management mechanism including medium earth orbit satellites to guarantee lightweight management.Secondly,considering latency-sensitive and latency-tolerant services,we formulate the problem of satellite-aircraft access and service management for civil aviation to ensure service continuity.Finally,we propose a proximal policy optimization-based access and service management algorithm to solve the formulated problem.Simulation results demonstrate the convergence and effectiveness of the proposed algorithm with satisfying the service continuity when applying to the UDLSN.展开更多
Nowadays,the utilization of renewable biomass as a substitute for petroleum-based feedstock in the synthesis of aerospace fuel has garnered significantattention.In this work,we use molecular sieve to catalyze the cont...Nowadays,the utilization of renewable biomass as a substitute for petroleum-based feedstock in the synthesis of aerospace fuel has garnered significantattention.In this work,we use molecular sieve to catalyze the controllable oligomerization of lignocellulose platform molecule furfuryl alcohol,which is prone to polymerize and generate furfuryl alcohol resin and other macromolecular substances.In order to reduce the formation of macromolecule polymers and enhance the yield of oligomers within the C9—C15 range,the reactive extraction strategy was implemented.Utilizing a low polar solvent,increasing the extraction phase content,employing a hydrophilic and weakly acidic molecular sieve are all beneficialfor enhancing the yield of the target products.Finally,under the optimal conditions,the conversion of furfuryl alcohol reaches 84.7%and the yield of the target products is improved from 10%—15%to 41.4%.After hydrodeoxygenation,a liquid fuel with paraffinas the main component was obtained.Moreover,the effect of substituents on the polymerization activity of furan derivatives was compared,the alkyl side chains as substituents can enhance both reactant activity and yield of target products.This study presents a viable approach for the efficientsynthesis of aviation fuel directly from bio-based furfuryl alcohol.展开更多
At the 15th Airshow China,held in Zhuhai,Guangdong Province,from 12 to 17 November 2024,China Southern Airlines,in collaboration with the Global Sustainable Transport Innovation and Knowledge Centre and Airbus,present...At the 15th Airshow China,held in Zhuhai,Guangdong Province,from 12 to 17 November 2024,China Southern Airlines,in collaboration with the Global Sustainable Transport Innovation and Knowledge Centre and Airbus,presented a report on the development of sustainable aviation fuel(SAF).展开更多
With the development of civil aviation industry,the number of retired aircraft is increasing year by year.How to deal with retired aircraft,build aviation,avoid damage to the ecological environment,and develop their r...With the development of civil aviation industry,the number of retired aircraft is increasing year by year.How to deal with retired aircraft,build aviation,avoid damage to the ecological environment,and develop their residual value has attracted widespread attention internationally,and gradually formed dismantling industry for the commercial and reuse of retired aircraft.From the perspective of the industrial chain,the essence of aircraft dismantling is how to maximize the value of highvalue assets at the of their life cycle,that is,to balance the value of aircraft parts and the value of the whole aircraft,which is the last chain in the complete industrial of civil aircraft from design,manufacturing to usage and retirement.The paper studied the dismantling industrial modes of civil aircraft,analyzed the problems and challenges faced by aircraft dismantling,and put forward relevant measures and suggestions,which point out the direction for the development of domestic civil aircraft dismantling industry.展开更多
Modifications in fuel spray characteristics fundamentally influence fuel–air mixing dynamics in diesel engines,thereby significantly affecting combustion performance and emission profiles.This study explores the oper...Modifications in fuel spray characteristics fundamentally influence fuel–air mixing dynamics in diesel engines,thereby significantly affecting combustion performance and emission profiles.This study explores the operational behavior of RP-5 aviation kerosene/diesel blended fuels in marine diesel engines.A spray visualization platform based on Mie scattering technology was developed to comparatively analyze the spray characteristics,ignition behavior,and soot emissions of RP-5 aviation kerosene,conventional-35#diesel,and their blends at varying mixing ratios(D100H0,D90H10,D70H30,D50H50,D30H70,D0H100).The findings demonstrate that,under constant injection pressure,aviation kerosene combustion results in a more uniform temperature field,characterized by lower core flame temperatures,broader high-temperature regions,and reduced soot concentrations with spatially homogeneous distribution and no pronounced peaks.In terms of spray dynamics,increasing the proportion of aviation kerosene leads to a marked widening of the spray cone angle.Meanwhile,spray penetration length exhibits a non-monotonic trend—initially decreasing and subsequently increasing—as the kerosene blending ratio rises.展开更多
Metal-support interactions and hydrogen spillover effects in heterogeneous catalysts play a crucial role in aromatic hydrogenation reactions;however,these effects are limited by the metal dispersion on the catalyst an...Metal-support interactions and hydrogen spillover effects in heterogeneous catalysts play a crucial role in aromatic hydrogenation reactions;however,these effects are limited by the metal dispersion on the catalyst and the number of acceptable H*receptors.This study prepares highly dispersed Ni nanoparticles(NPs)catalysts on a Beta substrate via precursor structure topology transformation.In contrast to traditional support materials,the coordination and electronic structure changes between the Ni NPs and the support were achieved,further optimizing the active interface sites and enhancing hydrogen activation and hydrogenation performance.Additionally,the-OH groups at the strong acid sites in zeolite effectively intensified the hydrogen spillover effect as receptors for H^(*)migration and anchoring,accelerating the hydrogenation rate of aromatic rings.Under solvent-free conditions,this catalyst was used for the hydrogenation reaction of aromatic-rich oils,directly producing a C_(8)-C_(14)branched cycloalkanes mixture with an aromatic conversion rate of>99%.The cycloalkanes mixture produced by this method features high density(0.92 g/mL)and a low freezing point(<-60℃),making it suitable for use as high-density aviation fuel or as an additive to enhance the volumetric heat value of conventional aviation fuels in practical applications.展开更多
Sustainable aviation fuel(SAF)production from biomass and biowaste streams is an attractive option for decarbonizing the aviation sector,one of the most-difficult-to-electrify transportation sectors.Despite ongoing co...Sustainable aviation fuel(SAF)production from biomass and biowaste streams is an attractive option for decarbonizing the aviation sector,one of the most-difficult-to-electrify transportation sectors.Despite ongoing commercialization efforts using ASTM-certified pathways(e.g.,lipid conversion,Fischer-Tropsch synthesis),production capacities are still inadequate due to limited feedstock supply and high production costs.New conversion technologies that utilize lignocellulosic feedstocks are needed to meet these challenges and satisfy the rapidly growing market.Combining bio-and chemo-catalytic approaches can leverage advantages from both methods,i.e.,high product selectivity via biological conversion,and the capability to build C-C chains more efficiently via chemical catalysis.Herein,conversion routes,catalysis,and processes for such pathways are discussed,while key challenges and meaningful R&D opportunities are identified to guide future research activities in the space.Bio-and chemo-catalytic conversion primarily utilize the carbohydrate fraction of lignocellulose,leaving lignin as a waste product.This makes lignin conversion to SAF critical in order to utilize whole biomass,thereby lowering overall production costs while maximizing carbon efficiencies.Thus,lignin valorization strategies are also reviewed herein with vital research areas identified,such as facile lignin depolymerization approaches,highly integrated conversion systems,novel process configurations,and catalysts for the selective cleavage of aryl C-O bonds.The potential efficiency improvements available via integrated conversion steps,such as combined biological and chemo-catalytic routes,along with the use of different parallel pathways,are identified as key to producing all components of a cost-effective,100%SAF.展开更多
Aviation kerosene RP-3 is extensively used in China.This paper details the measurement of the density of Chinese aviation kerosene RP-3 employing the flow method under high-pressure and high-temperature conditions.The...Aviation kerosene RP-3 is extensively used in China.This paper details the measurement of the density of Chinese aviation kerosene RP-3 employing the flow method under high-pressure and high-temperature conditions.The methodology utilizes circular tubes with two different diameters.The density of aviation kerosene RP-3 was experimentally measured for the first time within a pressure range from 6 MPa to 8 MPa and a temperature range from 323 K to 783 K,with a maximum relative uncertainty of 0.35%.The experimental setup used n-decane for calibration,achieving an average calibration error of 0.91%.The data indicate that the density of RP-3 ranges from 764 kg/m^(3)to 247 kg/m^(3)under the tested conditions.The results show that the density of kerosene RP-3 decreases with an increase in temperature at a constant pressure,and at a given temperature,a higher pressure results in a higher density.Polynomial fitting was applied to the data,resulting in the average absolute deviation of 1.09%,0.80%,and 0.76%at different pressures of 6,7,and 8 MPa,respectively.展开更多
The integration of Communicative Language Testing(CLT)principles with AI-driven automated assessment poses a significant challenge in professional language testing.Addressing this issue within the specific context of ...The integration of Communicative Language Testing(CLT)principles with AI-driven automated assessment poses a significant challenge in professional language testing.Addressing this issue within the specific context of Civil Aviation Ground Service English,this study explores pathways for their logical reconciliation.Through conceptual analysis and theoretical deduction,with a focus on human-AI interaction scenarios,we demonstrate that the synergy between CLT and AI stems from a shared focus on competency measurement.Key findings reveal that:(1)standardized competency dimensions in CLT can be operationalized into data-processable formats for AI;(2)within professional contexts,AI algorithms can be tailored using authentic service corpora to meet CLT’s demand for situational authenticity;and(3)a division of labor based on competency level-where AI handles standardized scoring of lower-order competencies and human-AI collaboration assesses higher-order competencies-effectively resolves the tension between CLT’s dynamic communication and AI’s static algorithms.Ultimately,the study constructs a three-dimensional integration framework encompassing“professional register,”“competency level,”and“human-AI division of labor,”offering a theoretical model for CLT-AI integration and a practical blueprint for innovating Civil Aviation Ground Service English assessment.展开更多
In order to improve the tribology behavior in aviation kerosene, molybdenum （Mo） modified layers were fabricated on Ti6Al4V base alloy using a double-glow plasma surface alloying technique. The morphology, microstru...In order to improve the tribology behavior in aviation kerosene, molybdenum （Mo） modified layers were fabricated on Ti6Al4V base alloy using a double-glow plasma surface alloying technique. The morphology, microstructure, microhardness and element depth distribution of the Mo modified layers were studied. The tribology properties of Ti6Al4V base alloy, Mo modified layers and 5CrMnMo tool steel sliding with GCr15 steel or QSn4-3 copper alloy counterparts in aviation kerosene were comparatively researched. The effect of roughness on the sliding wear behavior was discussed. The results indicate that the Mo modified layers with polishing treatments not only reduce the friction coefficient of Ti6Al4V base, but also enhance the wear resistance of the counterparts. The Mo modified layers have better tribology behavior than 5CrMnMo steel. It is also found that the wear volume loss of the counterparts is proportional to the value of roughness of Mo modified layers, which is related directly to the ploughing wear between micro convex bodies of the layers and counterparts.展开更多
The thermal degradation of two synthetic lubricants base oils, poly-a-olefins （PAO） and di-esters （DE）, was investigated under oxidative pyrolysis condition and their properties were characterized in simulated ＂a...The thermal degradation of two synthetic lubricants base oils, poly-a-olefins （PAO） and di-esters （DE）, was investigated under oxidative pyrolysis condition and their properties were characterized in simulated ＂areo-engine＂ by comparing the thermal stability and identifying the products of thermal decomposition as a function of exposure temperature. The characterization of the products were performed by means of Fourier transform infrared spectrometry （FTIR）, gas chromatography/mass spectrometry （GC/MS） and viscosity experiments. The results show that PAO has the lower thermal stability, being degraded at 200℃ different from 300 ℃ for DE. Several by-products are identified during the thermal degradation of two lubricant base oils. The majority of PAO products consist of alkenes and olefins, while more oxygen-contained organic compounds are detected in DE samples based on GC/MS analysis. The related reaction mechanisms are discussed based on the experimental results.展开更多
This paper analyzed 11 lubricating oil 50-1-4Ф samples of different base oil content （standard oil） and 28 used oil samples by Fourier transform mid-infrared spectrometer （FTIR）. First, the absorption peak of 1 4...This paper analyzed 11 lubricating oil 50-1-4Ф samples of different base oil content （standard oil） and 28 used oil samples by Fourier transform mid-infrared spectrometer （FTIR）. First, the absorption peak of 1 465 cm 1 was selected as the characteristic peak for determining their kinematic viscosities. And then correlation of the kinematic viscosity and the absorbance at characteristic peaks of corresponding infrared spectrum of standard oil and used oil samples was analyzed, re- spectively, and two regression equations were proposed. Finally, the regression equation of standard oil was corrected through other 20 new oil samples. The results show that determining kinematic viscosity of new lubricating oil 50-1-4Ф and the used one by FTIR is feasible and reliable.展开更多
A series of aviation lubrication oil 50-1-4φ samples were prepared with different RP-3 content, and then these sam- ples were analyzed by Fourier transform mid-infrared spectrometer （FTIR）. The infrared region of ...A series of aviation lubrication oil 50-1-4φ samples were prepared with different RP-3 content, and then these sam- ples were analyzed by Fourier transform mid-infrared spectrometer （FTIR）. The infrared region of 805--755 cm-1 was selected as quantitative area for determining fuel pollution level of aviation lubrication oil. Finally, correlation of the testing peak area and the fuel pollution level of corresponding samples were analyzed, and the regression equation was proposed. The results show that determining jet fuel pollution level of aviation lubricating oil by FTIR is feasible and reliable.展开更多
The needs analysis of Aviation Basic English course on ESP teaching is emphasized and the syllabus is designed here to instruct the better pre-job training for the students in the major of aircraft manufacturing techn...The needs analysis of Aviation Basic English course on ESP teaching is emphasized and the syllabus is designed here to instruct the better pre-job training for the students in the major of aircraft manufacturing technology.展开更多
The experimental apparatus to measure the mass diffusion coefficients of O2 in aviation fuel was constructed based on the digital holographic interferometry method. The theory of mass diffusion coefficient and interfe...The experimental apparatus to measure the mass diffusion coefficients of O2 in aviation fuel was constructed based on the digital holographic interferometry method. The theory of mass diffusion coefficient and interference image processing were introduced in detail. The accuracy of the experiment was verified by measuring the mass diffusion coefficient of 0.33 mol/L KCl in aqueous solution at 298.15 K. The mass diffusion coefficients of O_2 in RP3 and RP5 aviation fuels were measured at temperature from 278.15 K to 333.15 K, and the Arrhenius equation was employed to fit the experimental data. In terms of the Stokes-Einstein equation, the viscosities of these two aviation fuels were tested to estimate the correlation among mass diffusion coefficient, viscosity and temperature. A uniform polynomial calculation correlation was proposed to predict the mass diffusion coefficients of O_2 in both RP3 and RP5 aviation fuels, and its accuracy is considerably higher than that of the Stokes-Einstein equation.展开更多
We consider reliability engineering in modern civil aviation industry, and the related engineering activities and methods. We consider reliability in a broad sense, referring to other system characteristics that are r...We consider reliability engineering in modern civil aviation industry, and the related engineering activities and methods. We consider reliability in a broad sense, referring to other system characteristics that are related to it, like availability, maintainability, safety and durability. We covered the entire lifecycle of the equipment, including reliability requirement identification, reliability analysis and design, verification and validation of reliability requirements(typically involved in the equipment design and development phase), quality assurance(which typically enters in the manufacturing phase), and fault diagnosis and prognosis and maintenance(which are connected to the operation phase). Lessons learnt from reliability engineering practices in civil aviation industry are given, which might serve as reference for reliability managers and engineers, also from other industries with high reliability requirements.展开更多
Many variables affect the sealing performance, and their distribution characteristics are difficult to obtain with probabilistic methods owing to the high cost involved. Numerous problems in engineering are similar du...Many variables affect the sealing performance, and their distribution characteristics are difficult to obtain with probabilistic methods owing to the high cost involved. Numerous problems in engineering are similar due to the appearance of small-sample parameters. In this study, the sealing reliability of an aviation seal was defined as the research object, and an interval uncertainty method and multidimensional response surface were proposed to calculate the sealing reliability.Based on this, we first analyzed the failure mechanism of the aviation seal and established a leakage rate model. Then, based on the non-probabilistic interval model, an interval uncertainty method was proposed to construct the analytical model. With reference to the limit state equation from the structural reliability theory, the multidimensional response surface was used for fast calculation.Then, we chose the single-cylinder gas steering gear used in aircraft as the case study, its sealing reliability in working and non-working statuses were calculated, and the results were verified with the actual maintenance records. By analyzing the sensitivity of some variables, we can improve the sealing reliability of the aviation seal by improving the surface roughness only if the cost allows.Finally, we consider that the method proposed in this study realizes the application of smallsample uncertainty analysis in reliability analysis, and could provide a feasible way to solve the similar problems in engineering with multidimensional and small-sample parameters.展开更多
At high altitudes, an Aviation Oxygen Supply System （AOSS） protects pilots from low pressure and hypoxia by continuously providing oxygen corresponding to the pilots＇ dynamic respiratory properties. An AOSS mainly ...At high altitudes, an Aviation Oxygen Supply System （AOSS） protects pilots from low pressure and hypoxia by continuously providing oxygen corresponding to the pilots＇ dynamic respiratory properties. An AOSS mainly consists of oxygen supercharging machines which are used in a high-altitude flight cabin to supply pressurized oxygen to pilots. Therefore, it is of great significance to study the airflow dynamic characteristics of an AOSS for safe, continuous, and efficient oxygen supply. In this paper, an AOSS is firstly simplified and considered as a mechanical ventilation system. Then, its corresponding mathematical model is constructed. Next, to verify the mathematical model, a prototype AOSS with a lung simulator is proposed for an experimental study. Afterwards, to build a foundation for the optimization of the AOSS, the airflow dynamic characteristics of an aircraft are analyzed, and the effects of key parameters on the respiration system are researched. Through experimental and simulation studies, it can be concluded that the mathematical model is effective. Subsequently, for stability during the respiration process, we consider setting the equivalent throttling areas of the inspiration and expiration pipelines smaller within certain limits; additionally, an excessively high oxygen supply pressure will disturb smooth airflow, and in a low-pressure environment, the pressure can be 84 cmH20 lower than the standard atmospheric pressure. This research can be referred to in the design of an oxygen supply system and the study on optimization of airflow dynamic characteristics.展开更多
基金supported by the National Natural Science Foundation of China(72225012)the National Key Research and Development Program of China(2023YFB4302901)+1 种基金the National Natural Science Foundation of China(72288101,71822101,and 62201577)the Safety Capability Building Fund of the Civil Aviation Administration of China(ASSA2023/19).
文摘With the anticipated growth in air traffic complexity in the coming years,future civil aviation transportation system(CATS)is transforming into a complex cyber–physical–social system,surpassing all previous experiences in the history of civil aviation safety management.Therefore,a new safety concept based on a system-of-systems(SoS)perspective is proposed for the next-generation aviation.This article begins by elucidating the complexity of existing aviation risks and emphasizing the necessity for an updated safety concept.It then presents the challenges of current safety management and potential solutions from the new SoS perspective.To address future risks,the concept of SoS safety is introduced with the inspiration of the human immune system in terms of capability,logic,and architecture,which can serve as a guiding framework and methodology for safety engineering in complex large-scale CATS.This concept indicates the transition from“process and outcome-oriented”to“capability-oriented”intelligent safety management.Our research highlights the development directions and potential technological areas that need to be addressed at different stages of SoS safety.The integration of SoS design and operation through rapid iterations enabled by artificial intelligence(AI)will ultimately achieve endogenous SoS safety.
基金supported by the China Machinery Industry Education Association 2024 Industry-Education-Research Integration Project(Project No.:ZJJX24CY099)。
文摘This study examines a curriculum system developed at the College of Aviation Manufacturing Industry at Nanchang Hangkong University through Industry-Education Integration(I-E Integration).Drawing on engineering education principles and reforms in the Mechanical Design,Manufacturing,and Automation program,it aligns course design with industry needs,integrates technological advancements,and embeds production processes.The approach restructures modular course content based on aviation manufacturing technologies,implements project-based learning via a university-enterprise"factory-in-school"training base,and adopts an Outcome-Based Education(OBE)system for evaluation and improvement.This replicable model provides practical insights for industry-focused curriculum development.
基金supported in part by the National Key R&D Program of China under Grant 2020YFB1806104in part by Innovation and Entrepreneurship of Jiangsu Province High-level Talent Program+1 种基金in part by Natural Sciences and Engineering Research Council of Canada (NSERC)the support from Huawei
文摘With the deployment of ultra-dense low earth orbit(LEO)satellite constellations,LEO satellite access network(LEO-SAN)is envisioned to achieve global Internet coverage.Meanwhile,the civil aviation communications have increased dramatically,especially for providing airborne Internet services.However,due to dynamic service demands and onboard LEO resources over time and space,it poses huge challenges in satellite-aircraft access and service management in ultra-dense LEO satellite networks(UDLSN).In this paper,we propose a deep reinforcement learning-based approach for ultra-dense LEO satellite-aircraft access and service management.Firstly,we develop an airborne Internet architecture based on UDLSN and design a management mechanism including medium earth orbit satellites to guarantee lightweight management.Secondly,considering latency-sensitive and latency-tolerant services,we formulate the problem of satellite-aircraft access and service management for civil aviation to ensure service continuity.Finally,we propose a proximal policy optimization-based access and service management algorithm to solve the formulated problem.Simulation results demonstrate the convergence and effectiveness of the proposed algorithm with satisfying the service continuity when applying to the UDLSN.
基金support from the National Key Research and Development Program of China(2023YFB4103000)the Joint Fund of Ministry of Education for Equipment Pre-research(8091B03052304)the Haihe Laboratory of Sustainable Chemical Transformations for financialsupport.
文摘Nowadays,the utilization of renewable biomass as a substitute for petroleum-based feedstock in the synthesis of aerospace fuel has garnered significantattention.In this work,we use molecular sieve to catalyze the controllable oligomerization of lignocellulose platform molecule furfuryl alcohol,which is prone to polymerize and generate furfuryl alcohol resin and other macromolecular substances.In order to reduce the formation of macromolecule polymers and enhance the yield of oligomers within the C9—C15 range,the reactive extraction strategy was implemented.Utilizing a low polar solvent,increasing the extraction phase content,employing a hydrophilic and weakly acidic molecular sieve are all beneficialfor enhancing the yield of the target products.Finally,under the optimal conditions,the conversion of furfuryl alcohol reaches 84.7%and the yield of the target products is improved from 10%—15%to 41.4%.After hydrodeoxygenation,a liquid fuel with paraffinas the main component was obtained.Moreover,the effect of substituents on the polymerization activity of furan derivatives was compared,the alkyl side chains as substituents can enhance both reactant activity and yield of target products.This study presents a viable approach for the efficientsynthesis of aviation fuel directly from bio-based furfuryl alcohol.
文摘At the 15th Airshow China,held in Zhuhai,Guangdong Province,from 12 to 17 November 2024,China Southern Airlines,in collaboration with the Global Sustainable Transport Innovation and Knowledge Centre and Airbus,presented a report on the development of sustainable aviation fuel(SAF).
文摘With the development of civil aviation industry,the number of retired aircraft is increasing year by year.How to deal with retired aircraft,build aviation,avoid damage to the ecological environment,and develop their residual value has attracted widespread attention internationally,and gradually formed dismantling industry for the commercial and reuse of retired aircraft.From the perspective of the industrial chain,the essence of aircraft dismantling is how to maximize the value of highvalue assets at the of their life cycle,that is,to balance the value of aircraft parts and the value of the whole aircraft,which is the last chain in the complete industrial of civil aircraft from design,manufacturing to usage and retirement.The paper studied the dismantling industrial modes of civil aircraft,analyzed the problems and challenges faced by aircraft dismantling,and put forward relevant measures and suggestions,which point out the direction for the development of domestic civil aircraft dismantling industry.
基金supported by Innovation Research Project for the training of high-level scientific and technological talents(Technical expert talents)of the Armed Police Force ZZKY20222415Research and Innovation Team in Marine Propulsion Technology,China Coast Guard Academy.
文摘Modifications in fuel spray characteristics fundamentally influence fuel–air mixing dynamics in diesel engines,thereby significantly affecting combustion performance and emission profiles.This study explores the operational behavior of RP-5 aviation kerosene/diesel blended fuels in marine diesel engines.A spray visualization platform based on Mie scattering technology was developed to comparatively analyze the spray characteristics,ignition behavior,and soot emissions of RP-5 aviation kerosene,conventional-35#diesel,and their blends at varying mixing ratios(D100H0,D90H10,D70H30,D50H50,D30H70,D0H100).The findings demonstrate that,under constant injection pressure,aviation kerosene combustion results in a more uniform temperature field,characterized by lower core flame temperatures,broader high-temperature regions,and reduced soot concentrations with spatially homogeneous distribution and no pronounced peaks.In terms of spray dynamics,increasing the proportion of aviation kerosene leads to a marked widening of the spray cone angle.Meanwhile,spray penetration length exhibits a non-monotonic trend—initially decreasing and subsequently increasing—as the kerosene blending ratio rises.
基金financially supported by the National Natural Science Foundation of China(Grant 22278439,21776313)the Shandong Province Higher Education Youth Innovation Technology Support Program(Grant 2022KJ074)。
文摘Metal-support interactions and hydrogen spillover effects in heterogeneous catalysts play a crucial role in aromatic hydrogenation reactions;however,these effects are limited by the metal dispersion on the catalyst and the number of acceptable H*receptors.This study prepares highly dispersed Ni nanoparticles(NPs)catalysts on a Beta substrate via precursor structure topology transformation.In contrast to traditional support materials,the coordination and electronic structure changes between the Ni NPs and the support were achieved,further optimizing the active interface sites and enhancing hydrogen activation and hydrogenation performance.Additionally,the-OH groups at the strong acid sites in zeolite effectively intensified the hydrogen spillover effect as receptors for H^(*)migration and anchoring,accelerating the hydrogenation rate of aromatic rings.Under solvent-free conditions,this catalyst was used for the hydrogenation reaction of aromatic-rich oils,directly producing a C_(8)-C_(14)branched cycloalkanes mixture with an aromatic conversion rate of>99%.The cycloalkanes mixture produced by this method features high density(0.92 g/mL)and a low freezing point(<-60℃),making it suitable for use as high-density aviation fuel or as an additive to enhance the volumetric heat value of conventional aviation fuels in practical applications.
基金supported by the Center for Bioenergy Innovation(CBI)supported by the Office of Biological and Environmental Research in the DOE Office of Science and led by Oak Ridge National Laboratory.Oak Ridge National Laboratory is managed by UT-Battelle,LLC for the US DOE under Contract Number DE-AC05-00OR22725+2 种基金authored in part by the Na-tional Renewable Energy Laboratory,operated by Alliance for Sustainable Energy,LLC,for the U.S.Department of Energy(DOE)under Contract No.DE-LC-000L054provided by the U.S.Department of Energy(DOE),Office of Energy Efficiency and Renewable Energy(EERE),and Bioenergy Technologies Office(BETO)at the Pacific Northwest National Laboratory(PNNL)under Contract No.DE-AC05-76RL01830supported by Laboratory Directed Research and Development(LDRD)funding from Argonne National Laboratory,provided by the Director,Office of Science,of the U.S.Department of Energy under Contract No.DE-AC02-06CH11357。
文摘Sustainable aviation fuel(SAF)production from biomass and biowaste streams is an attractive option for decarbonizing the aviation sector,one of the most-difficult-to-electrify transportation sectors.Despite ongoing commercialization efforts using ASTM-certified pathways(e.g.,lipid conversion,Fischer-Tropsch synthesis),production capacities are still inadequate due to limited feedstock supply and high production costs.New conversion technologies that utilize lignocellulosic feedstocks are needed to meet these challenges and satisfy the rapidly growing market.Combining bio-and chemo-catalytic approaches can leverage advantages from both methods,i.e.,high product selectivity via biological conversion,and the capability to build C-C chains more efficiently via chemical catalysis.Herein,conversion routes,catalysis,and processes for such pathways are discussed,while key challenges and meaningful R&D opportunities are identified to guide future research activities in the space.Bio-and chemo-catalytic conversion primarily utilize the carbohydrate fraction of lignocellulose,leaving lignin as a waste product.This makes lignin conversion to SAF critical in order to utilize whole biomass,thereby lowering overall production costs while maximizing carbon efficiencies.Thus,lignin valorization strategies are also reviewed herein with vital research areas identified,such as facile lignin depolymerization approaches,highly integrated conversion systems,novel process configurations,and catalysts for the selective cleavage of aryl C-O bonds.The potential efficiency improvements available via integrated conversion steps,such as combined biological and chemo-catalytic routes,along with the use of different parallel pathways,are identified as key to producing all components of a cost-effective,100%SAF.
基金supported by the Science Center for Gas Turbine Project,China(No.P2022-C-II-005-001)。
文摘Aviation kerosene RP-3 is extensively used in China.This paper details the measurement of the density of Chinese aviation kerosene RP-3 employing the flow method under high-pressure and high-temperature conditions.The methodology utilizes circular tubes with two different diameters.The density of aviation kerosene RP-3 was experimentally measured for the first time within a pressure range from 6 MPa to 8 MPa and a temperature range from 323 K to 783 K,with a maximum relative uncertainty of 0.35%.The experimental setup used n-decane for calibration,achieving an average calibration error of 0.91%.The data indicate that the density of RP-3 ranges from 764 kg/m^(3)to 247 kg/m^(3)under the tested conditions.The results show that the density of kerosene RP-3 decreases with an increase in temperature at a constant pressure,and at a given temperature,a higher pressure results in a higher density.Polynomial fitting was applied to the data,resulting in the average absolute deviation of 1.09%,0.80%,and 0.76%at different pressures of 6,7,and 8 MPa,respectively.
基金supported by the Vocational Education Research Project from China Commercial Technicians Association:“Research on the Construction and Application of AI-Enabled English Testing System for Civil Aviation Ground Services”(20ZSJYB20250420)the Education Science Planning Projects(Higher Education Special Program)from Guangdong Provincial Department of Education:“Research on the Evaluation System of Digital Competence in Curriculum Ideology and Politics for Higher Vocational Teachers in Guangdong under the Background of Educational Digitalization”(2024GXJK877)“Digital Empowerment for High-Quality Development in Guangdong:An Innovative Study on Cultivating Interdisciplinary Foreign Language Talents”(2023GXJK691).
文摘The integration of Communicative Language Testing(CLT)principles with AI-driven automated assessment poses a significant challenge in professional language testing.Addressing this issue within the specific context of Civil Aviation Ground Service English,this study explores pathways for their logical reconciliation.Through conceptual analysis and theoretical deduction,with a focus on human-AI interaction scenarios,we demonstrate that the synergy between CLT and AI stems from a shared focus on competency measurement.Key findings reveal that:(1)standardized competency dimensions in CLT can be operationalized into data-processable formats for AI;(2)within professional contexts,AI algorithms can be tailored using authentic service corpora to meet CLT’s demand for situational authenticity;and(3)a division of labor based on competency level-where AI handles standardized scoring of lower-order competencies and human-AI collaboration assesses higher-order competencies-effectively resolves the tension between CLT’s dynamic communication and AI’s static algorithms.Ultimately,the study constructs a three-dimensional integration framework encompassing“professional register,”“competency level,”and“human-AI division of labor,”offering a theoretical model for CLT-AI integration and a practical blueprint for innovating Civil Aviation Ground Service English assessment.
基金Projects (50671085, 51171154) supported by the National Natural Science Foundation of ChinaProject (2007AA03Z521) supported by the High-tech Research and Development Program of China
文摘In order to improve the tribology behavior in aviation kerosene, molybdenum （Mo） modified layers were fabricated on Ti6Al4V base alloy using a double-glow plasma surface alloying technique. The morphology, microstructure, microhardness and element depth distribution of the Mo modified layers were studied. The tribology properties of Ti6Al4V base alloy, Mo modified layers and 5CrMnMo tool steel sliding with GCr15 steel or QSn4-3 copper alloy counterparts in aviation kerosene were comparatively researched. The effect of roughness on the sliding wear behavior was discussed. The results indicate that the Mo modified layers with polishing treatments not only reduce the friction coefficient of Ti6Al4V base, but also enhance the wear resistance of the counterparts. The Mo modified layers have better tribology behavior than 5CrMnMo steel. It is also found that the wear volume loss of the counterparts is proportional to the value of roughness of Mo modified layers, which is related directly to the ploughing wear between micro convex bodies of the layers and counterparts.
基金Supported by the Fund from the Air Force Armament Department of China for Innovative Research Group(Grant KJ2012283)
文摘The thermal degradation of two synthetic lubricants base oils, poly-a-olefins （PAO） and di-esters （DE）, was investigated under oxidative pyrolysis condition and their properties were characterized in simulated ＂areo-engine＂ by comparing the thermal stability and identifying the products of thermal decomposition as a function of exposure temperature. The characterization of the products were performed by means of Fourier transform infrared spectrometry （FTIR）, gas chromatography/mass spectrometry （GC/MS） and viscosity experiments. The results show that PAO has the lower thermal stability, being degraded at 200℃ different from 300 ℃ for DE. Several by-products are identified during the thermal degradation of two lubricant base oils. The majority of PAO products consist of alkenes and olefins, while more oxygen-contained organic compounds are detected in DE samples based on GC/MS analysis. The related reaction mechanisms are discussed based on the experimental results.
文摘This paper analyzed 11 lubricating oil 50-1-4Ф samples of different base oil content （standard oil） and 28 used oil samples by Fourier transform mid-infrared spectrometer （FTIR）. First, the absorption peak of 1 465 cm 1 was selected as the characteristic peak for determining their kinematic viscosities. And then correlation of the kinematic viscosity and the absorbance at characteristic peaks of corresponding infrared spectrum of standard oil and used oil samples was analyzed, re- spectively, and two regression equations were proposed. Finally, the regression equation of standard oil was corrected through other 20 new oil samples. The results show that determining kinematic viscosity of new lubricating oil 50-1-4Ф and the used one by FTIR is feasible and reliable.
文摘A series of aviation lubrication oil 50-1-4φ samples were prepared with different RP-3 content, and then these sam- ples were analyzed by Fourier transform mid-infrared spectrometer （FTIR）. The infrared region of 805--755 cm-1 was selected as quantitative area for determining fuel pollution level of aviation lubrication oil. Finally, correlation of the testing peak area and the fuel pollution level of corresponding samples were analyzed, and the regression equation was proposed. The results show that determining jet fuel pollution level of aviation lubricating oil by FTIR is feasible and reliable.
文摘The needs analysis of Aviation Basic English course on ESP teaching is emphasized and the syllabus is designed here to instruct the better pre-job training for the students in the major of aircraft manufacturing technology.
基金supported by the Aeronautical Science Foundation of China(No.20132852040)the Fundation of Graduate Innovation Center in NUAA(No.kfjj20170116)+1 种基金the Fundamental Research Funds for the Central Universitiesthe Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘The experimental apparatus to measure the mass diffusion coefficients of O2 in aviation fuel was constructed based on the digital holographic interferometry method. The theory of mass diffusion coefficient and interference image processing were introduced in detail. The accuracy of the experiment was verified by measuring the mass diffusion coefficient of 0.33 mol/L KCl in aqueous solution at 298.15 K. The mass diffusion coefficients of O_2 in RP3 and RP5 aviation fuels were measured at temperature from 278.15 K to 333.15 K, and the Arrhenius equation was employed to fit the experimental data. In terms of the Stokes-Einstein equation, the viscosities of these two aviation fuels were tested to estimate the correlation among mass diffusion coefficient, viscosity and temperature. A uniform polynomial calculation correlation was proposed to predict the mass diffusion coefficients of O_2 in both RP3 and RP5 aviation fuels, and its accuracy is considerably higher than that of the Stokes-Einstein equation.
基金supported by the National Natural Science Foundation of China (Nos. 61573043, 71671009 and 71601010)
文摘We consider reliability engineering in modern civil aviation industry, and the related engineering activities and methods. We consider reliability in a broad sense, referring to other system characteristics that are related to it, like availability, maintainability, safety and durability. We covered the entire lifecycle of the equipment, including reliability requirement identification, reliability analysis and design, verification and validation of reliability requirements(typically involved in the equipment design and development phase), quality assurance(which typically enters in the manufacturing phase), and fault diagnosis and prognosis and maintenance(which are connected to the operation phase). Lessons learnt from reliability engineering practices in civil aviation industry are given, which might serve as reference for reliability managers and engineers, also from other industries with high reliability requirements.
基金supported in part from the Fundamental Research Project funded by the Ministry of Industry and Information Technology of the People’s Republic of China
文摘Many variables affect the sealing performance, and their distribution characteristics are difficult to obtain with probabilistic methods owing to the high cost involved. Numerous problems in engineering are similar due to the appearance of small-sample parameters. In this study, the sealing reliability of an aviation seal was defined as the research object, and an interval uncertainty method and multidimensional response surface were proposed to calculate the sealing reliability.Based on this, we first analyzed the failure mechanism of the aviation seal and established a leakage rate model. Then, based on the non-probabilistic interval model, an interval uncertainty method was proposed to construct the analytical model. With reference to the limit state equation from the structural reliability theory, the multidimensional response surface was used for fast calculation.Then, we chose the single-cylinder gas steering gear used in aircraft as the case study, its sealing reliability in working and non-working statuses were calculated, and the results were verified with the actual maintenance records. By analyzing the sensitivity of some variables, we can improve the sealing reliability of the aviation seal by improving the surface roughness only if the cost allows.Finally, we consider that the method proposed in this study realizes the application of smallsample uncertainty analysis in reliability analysis, and could provide a feasible way to solve the similar problems in engineering with multidimensional and small-sample parameters.
文摘At high altitudes, an Aviation Oxygen Supply System （AOSS） protects pilots from low pressure and hypoxia by continuously providing oxygen corresponding to the pilots＇ dynamic respiratory properties. An AOSS mainly consists of oxygen supercharging machines which are used in a high-altitude flight cabin to supply pressurized oxygen to pilots. Therefore, it is of great significance to study the airflow dynamic characteristics of an AOSS for safe, continuous, and efficient oxygen supply. In this paper, an AOSS is firstly simplified and considered as a mechanical ventilation system. Then, its corresponding mathematical model is constructed. Next, to verify the mathematical model, a prototype AOSS with a lung simulator is proposed for an experimental study. Afterwards, to build a foundation for the optimization of the AOSS, the airflow dynamic characteristics of an aircraft are analyzed, and the effects of key parameters on the respiration system are researched. Through experimental and simulation studies, it can be concluded that the mathematical model is effective. Subsequently, for stability during the respiration process, we consider setting the equivalent throttling areas of the inspiration and expiration pipelines smaller within certain limits; additionally, an excessively high oxygen supply pressure will disturb smooth airflow, and in a low-pressure environment, the pressure can be 84 cmH20 lower than the standard atmospheric pressure. This research can be referred to in the design of an oxygen supply system and the study on optimization of airflow dynamic characteristics.
