PLOS ONE: [sortOrder=DATE_NEWEST_FIRST, sort=Date, newest first, q=subject:"Aerospace engineering"]PLOShttps://journals.plos.org/plosone/webmaster@plos.orgaccelerating the publication of peer-reviewed sciencehttps://journals.plos.org/plosone/search/feed/atom?sortOrder=DATE_NEWEST_FIRST&unformattedQuery=subject:%22Aerospace+engineering%22&sort=Date,+newest+firstAll PLOS articles are Open Access.https://journals.plos.org/plosone/resource/img/favicon.icohttps://journals.plos.org/plosone/resource/img/favicon.ico2024-03-28T18:12:21ZCollaborative optimization model and algorithm for airport capacity and traffic flow allocationPeinan HeWeijun Pan10.1371/journal.pone.02985402024-03-22T14:00:00Z2024-03-22T14:00:00Z<p>by Peinan He, Weijun Pan</p>
How to efficiently utilize the existing airport capacity without physical expansion and considerable economic inputs to meet air traffic needs is one of the important tasks of air traffic management. To improve the efficiency of capacity utilization, it is necessary to find the actual airport capacity properly. In this work, taking Shuangliu International Airport as an example, a methodology for capacity estimation is proposed that combines the empirical method with an analytical approach that uses historical performance data from the airport to construct a capacity envelope to approximate the airport’s actual capacity to the greatest extent, establishes a collaborative optimization model that reflects the inherent relations between airport capacity and arrival and departure traffic demand, adopts an improved optimization algorithm to solve the model, and generates an optimal flight allocation scheme. Priority ratio is introduced to dynamically adjust management preferences for arrival and departure traffic demand to further reveal the synergy mechanism between departure and arrival traffic flow demand and the airport capacity. The result shows that the Flight On-time Performance rate is lifted by 6% in the case study which proves the feasibility of the proposed method, demonstrating its value for maximizing airport capacity and traffic flow demand without requiring expansions on airport scales.A fuzzy interval optimization approach for <i>p</i>-hub median problem under uncertain informationYu WangTao ZhuKaibo YuanXin Li10.1371/journal.pone.02972952024-03-15T14:00:00Z2024-03-15T14:00:00Z<p>by Yu Wang, Tao Zhu, Kaibo Yuan, Xin Li</p>
Stochastic and robust optimization approaches often result in sub-optimal solutions for the uncertain <i>p</i>-hub median problem when continuous design parameters are discretized to form different environmental scenarios. To solve this problem, this paper proposes a triangular fuzzy number model for the Non-Strict Uncapacitated Multi-Allocation <i>p</i>-hub Median Problem. To enhance the quality and the speed of optimization, a novel optimization approach, combining the triangular fuzzy number evaluation index with the Genetic-Tabu Search algorithm, is proposed. During the iterations of the Genetic-Tabu Search algorithm for finding the optimal solution, the fitness of fuzzy hub schemes is calculated by considering the relative positional relationships of triangular fuzzy number membership functions. This approach directly addresses the triangular fuzzy number model and ensures the integrity of information in the <i>p</i>-hub problem as much as possible. It is verified by the classic Civil Aeronautics Board and several self-constructed data sets. The results indicate that, compared to the traditional Genetic Algorithm and Tabu Search algorithm, the Genetic-Tabu Search algorithm reduces average computation time by 49.05% and 40.93%, respectively. Compared to traditional random, robust, and real-number-based optimization approaches, the proposed optimization approach reduces the total cost in uncertain environments by 1.47%, 2.80%, and 8.85%, respectively.Proximity to the water surface markedly enhances the force production on underwater flapping wingsShantanu S. BhatAlbert MedinaFang-Bao TianJohn YoungJoseph C. S. LaiSridhar Ravi10.1371/journal.pone.02995422024-03-13T14:00:00Z2024-03-13T14:00:00Z<p>by Shantanu S. Bhat, Albert Medina, Fang-Bao Tian, John Young, Joseph C. S. Lai, Sridhar Ravi</p>
The potential application of flapping wings in micro-aerial vehicles is gaining interest due to their ability to generate high lift even in confined spaces. Most studies in the past have investigated hovering wings as well as those flapping near solid surfaces. However, the presence of surface tension at the water-air interface and the ability of the water surface to move might differentiate its response to the proximity of wings, compared to that of solid surfaces. Motivated by underwater, amphibian robots and several underwater experimental studies on flapping wings, our study investigated the effects of the proximity of flapping wings to the water surface at low Reynolds numbers (<i>Re</i> = 3400). Experiments were performed on a rectangular wing in a water tank with prescribed flapping kinematics and the aerodynamic forces were measured. The effects of surface proximity on the wing in its both upright and inverted orientations were studied. Broadly, the mean lift and drag coefficients in both orientations decreased significantly (by up to 60%) as the distance from the water surface was increased. In the case of the upright orientation, the mean lift coefficient was slightly decreased very close to the water surface with its peak being observed at the normalized clearance of h / c ¯ = 0 . 07. Overall, the study revealed an enhancement in the aerodynamic forces closer to the water surface.Development of combined hypersonic test facility for aerothermodynamic testingSungmo YangIlsung ChoiGisu Park10.1371/journal.pone.02981132024-02-14T14:00:00Z2024-02-14T14:00:00Z<p>by Sungmo Yang, Ilsung Choi, Gisu Park</p>
In this study, a combined test facility was developed using a combination of an arc-jet tunnel and a shock tunnel for aerothermodynamic testing. The performance validation of individual parts was performed, and results were obtained from the combined test. A small-scale Huels-type arc-jet tunnel was used to preheat the test model by aerodynamic heating before conducting the experiments in the shock tunnel to duplicate the hot surfaces of flight objects encountered during hypersonic flight. The high-enthalpy flow in the arc-jet tunnel provided a heat flux of 1.99±0.03 MW/m<sup>2</sup> for a flat-faced model of 10 mm diameters, and the flow condition of the shock tunnel used in this study simulated a Mach 5 flight at a pressure altitude of about 24 km. The two combined experiments employing different shape and material models were carried out to examine the effect of aerothermodynamic phenomena. In the first experiment, the effect of ablation-induced shape change on the fluid-structure was investigated using a cone model manufactured of AL6061 material. The effect of surface roughness on the fluid-structure was examined in the second experiment, which used a hemisphere model constructed of STS303 material. Although substantial findings could not be validated due to the limits of qualitative evaluations utilizing visualization methods, however preheating-related changes in surface roughness were found. As a follow-up study, a force measuring experiment based on the test procedures is being carried out at this facility utilizing a preheated model with an accelerometer. The performance and experimental results obtained using this integrated setup are discussed in detail, highlighting the potential of this combined hypersonic test facility.The research of touch screen usability in civil aircraft cockpitXiaoli WangWei GuoZhenwei ZhongRui ZengJiong ZhangLijing Wang10.1371/journal.pone.02928492024-02-08T14:00:00Z2024-02-08T14:00:00Z<p>by Xiaoli Wang, Wei Guo, Zhenwei Zhong, Rui Zeng, Jiong Zhang, Lijing Wang</p>
With the advancement of touch screen technology, the application of touch screens in civil aircraft cockpits has become increasingly popular. However, further analysis and research are required to fully promote its applications. The paper researched the usability of touch screens in aircraft cockpit considering the operation performance and subjective NASA-TLX workload evaluation, conducted experimental research on three touch gestures: click, drag, and zoom. Additionally, a comparative analysis was conducted on the touch performance under different layouts, positions, touch sizes, dragging direction angles, and zoom multiples. The touch performance indicators include operation time, error rate, operation speed, and workload. The experimental results show that the 21 mm size has the minimum operation time and workload, and 18 mm size has the lowest error rate in the clicking tasks. Additionally, the performance and workload of the captain’s layout are better than those of the co-pilot’s layout, and the performance of the center console position is best. The operation speed of the dragging tasks is faster when performed at position R3 compared to other positions. The dragging moving angles with better operation speed are 80°-190° and 250°-290°. The operation performance and workload of the zooming tasks vary depending on the zoom multiples. As the multiple increases, the operation time and workload also increase. There is no difference in operation performance or workload between zooming in and zooming out. The paper provides experimental support and suggestions based on human operation and subjective NASA-TLX workload evaluation for the application of touch screens in civil aircraft cockpits.Effect of acute stress on working memory in pilots: Investigating the modulatory role of memory loadYaowei LiangXing PengYu MengYueying LiuQi ZhuZhi XuJiazhong Yang10.1371/journal.pone.02882212024-01-25T14:00:00Z2024-01-25T14:00:00Z<p>by Yaowei Liang, Xing Peng, Yu Meng, Yueying Liu, Qi Zhu, Zhi Xu, Jiazhong Yang</p>
Many practitioners, such as pilots, frequently face working memory (WM) demands under acute stress environments, while the effect of acute stress on WM has not been conclusively studied because it is moderated by a variety of factors. The current study investigated how acute stress affects pilots’ WM under different memory load conditions. There are 42 pilots conducting the experiments, consisting of 21 stress group participants experiencing the Trier Social Stress Test (TSST) and 21 control group participants experiencing the controlled TSST (C-TSST). Subsequently, both groups performed N-back tasks under three memory load conditions (0-back, 1-back, and 2-back). State Anxiety Inventory (S-AI), heart rate (HR), and salivary cortisol concentrations (SCC) were collected to analyze acute stress induction. The results revealed that (1) the TSST could effectively induce acute stress with higher S-AI, HR, and SCC; (2) higher memory load reduces WM accuracy (ACC) and delays response times (RT); (3) acute stress increases WM ACC under moderate load conditions (1-back task). These results suggest that acute stress may not necessarily impair WM and even improve WM performance under certain memory load conditions. Potential mechanisms of acute stress effects on WM and alternative explanations for the modulatory role of memory load consistent with the emotion and motivation regulation theory are discussed. These findings not only provide insight into the field of acute stress and WM but are also beneficial for pilot training and the development of stress management strategies.Optimization of cabin seating arrangement strategies based on the Wells–Riley risk theoryYanxi LiuXuan ChengDengzhao TangXinyue Wang10.1371/journal.pone.02943452023-11-20T14:00:00Z2023-11-20T14:00:00Z<p>by Yanxi Liu, Xuan Cheng, Dengzhao Tang, Xinyue Wang</p>
Civil aviation transport is an important source of global respiratory disease spread due to the closely-spaced environment. In order to reduce the probability of infection of passengers, an improved Wells-Riley model for cabin passenger risk assessment have been given in this work, the cabin ventilation and passenger nose and mouth orientation were considered. The model’s effectiveness has been verified with published data. Finally, how the load factor and use of an empty seat scheme are associated with the number of infected people was assessed. The results demonstrated that the number of infected people positively correlates with the passenger load factor, and the most suitable load factor can be determined by controlling the final number of infected people with the condition of the epidemic situation in the departure city. Additionally, infection risk was found to be lower among passengers in window seats than in those in aisle seats and middle seats, and keeping empty seats in the middle or aisle could reduce the cabin average probability of infection by up to 37.47%. Using the model developed here, airlines can determine the optimal load factor threshold and seating arrangement strategy to improve economic benefits and reduce the probability of passenger infection.Exploring factors affecting the adoption and continuance usage of drone in healthcare: The role of the environmentJohn Serbe MarfoKwadwo KyeremehPasty AsamoahMatilda Kokui Owusu-BioAfia Frimpomaa Asare Marfo10.1371/journal.pdig.00002662023-11-07T14:00:00Z2023-11-07T14:00:00Z<p>by John Serbe Marfo, Kwadwo Kyeremeh, Pasty Asamoah, Matilda Kokui Owusu-Bio, Afia Frimpomaa Asare Marfo</p>
Drone technologies and healthcare delivery have attracted scholarly attention over the years. Studies have acknowledged the positive impact of the adoption and usage of drone technologies for healthcare delivery. We argue however that, knowledge is lacking on the role of the environment in drone technologies adoption, usage and continuance usage. An examination of 330 health facilities that engage in the use of drone services from Zipline Ghana showed that the environment inversely moderates the relationship between actual usage and intention to continue usage, suggesting that reducing the influence of environmental factors will increase the impact actual usage has on the continuance usage of drone technology in healthcare delivery.Numerical study of the tire hydroplaning behavior of aircraft on grooved concrete pavementJing CaiNizhi DuNing ZhouYue LiXuan DaiHeng Zhang10.1371/journal.pone.02927012023-11-01T14:00:00Z2023-11-01T14:00:00Z<p>by Jing Cai, Nizhi Du, Ning Zhou, Yue Li, Xuan Dai, Heng Zhang</p>
Safe operation is crucial for civil aviation, and reducing the risk of aircraft tire hydroplaning is essential for civil aviation safety. Here, a new 3D aircraft tire-grooved (smooth) wet pavement model based on the coupled Eulerian-Lagrangian (CEL) algorithm for the A320 aircraft was developed, and the effect of the ground contact area of an aircraft tire on the hydrodynamic pressure and support force of the tire under smooth and grooved wet pavement conditions was investigated. The results indicate that at the same taxiing speed, the ground contact area of the aircraft tire under the grooved wet-pavement condition is reduced by 19.8% compared to the smoothed wet-pavement condition, which is reduced by 6.2%. Similar patterns are observed for the hydrodynamic pressure and the critical hydrodynamic speed during landing and taking-off procedures, with upper and lower limited values obtained through the simulation results. Additionally, the predicted correction factor of the hydroplaning speed at different water film thicknesses is compared with those values obtained via the NASA formula. A comparison shows that the NASA formula underestimates the critical hydroplaning speed during the landing procedure. The corresponding correction factor will be less than 1.0 when the water film thickness reaches a critical value of 7.66 mm.Joint duration-cost-quality optimization model for complex product supply chains under contingency conditionsYunzhe LiPeng DongWeimin Ye10.1371/journal.pone.02920102023-10-16T14:00:00Z2023-10-16T14:00:00Z<p>by Yunzhe Li, Peng Dong, Weimin Ye</p>
The Graphical Evaluation and Review Technique (GERT) and complex networks are used to simulate and analyse complex product supply chain networks based on the characteristics of complex product supply chain networks. And the traditional GERT is improved by constructing a grey parametric GERT network with restricted output results, taking into account the fact that the duration, product quality and product cost of each supplier in a complex product supply chain are interval values rather than definite values, and that customers have restrictions on the duration, product quality and product cost of the final product. The functional relationship between product quality, product cost and duration is analysed, and two satisfaction functions for duration and cost are constructed in order to quantify the multi-objective requirements of shortening duration, saving product cost and guaranteeing product quality for complex products under emergency situations. Then, a duration-cost-quality model for complex product supply chains in contingency situations is constructed to obtain the better duration, product cost and product quality of each supplier by optimising the indicator parameters in the network. Finally, the scientific validity and effectiveness of the model and method are verified by means of arithmetic example. The results show that the method is able to analyse the optimal duration, product quality and product cost of each supplier, and the main manufacturer can obtain an optimised combination of duration, cost and quality for a complex product supply chain in different contingency situation. To further promote the sustainable and secure development of complex product supply chains, this paper also suggests the integration of data sharing and blockchain technology with complex product supply chains to develop dynamic supply chain feedback management systems.Dynamic avoidance decision method for civil aircraft in a suborbital debris hazard zoneWantong ChenTianru DiaoShiyu RenShuguang SunRuihua Liu10.1371/journal.pone.02895002023-08-01T14:00:00Z2023-08-01T14:00:00Z<p>by Wantong Chen, Tianru Diao, Shiyu Ren, Shuguang Sun, Ruihua Liu</p>
Closing the static suborbital debris hazard zone method leads to low airspace resource utilization and long delays for civil aircraft, while the dynamic delineation of suborbital debris hazard zone method can solve the above phenomena. However, the existing research lacks the decision instruction for civil aircraft to avoid the dynamic suborbital debris hazard zone. To address the above problems, this paper creates probability ellipsoids of suborbital debris with different ballistic coefficients in the two-dimensional plane and use the divide-and-conquer algorithm for the dynamic delineation of the suborbital debris hazard zone. The suborbital debris hazard zone is extended outward by 10 km. Subsequently, the standard A* algorithm, the standard Lazy theta* algorithm, the improved Lazy theta* algorithm, and a flight path planning strategy are designed to avoid the suborbital debris hazard zone and provide safe dynamic avoidance commands for civil aircraft with fixed time intervals. The simulation results show that the average area of the dynamically delineated suborbital debris hazard zone is lower than the traditional static no-fly zone; the standard A* algorithm and improved Lazy theta* algorithm provides shorter flight path lengths and flight time and fewer waypoints in windless and windy conditions, respectively.Critical and steady-state characteristics of delay propagation in an airport networkHong-Guang YaoHang Zhang10.1371/journal.pone.02882002023-07-07T14:00:00Z2023-07-07T14:00:00Z<p>by Hong-Guang Yao, Hang Zhang</p>
In this work, we established a density equation for delayed airports to investigate the horizontal propagation mechanism of delays among airports in an airport network. We explored the critical conditions, steady-state features, and scale of the delay propagation, and designed a simulation system to verify the accuracy of the results. The results indicated that, due to the no-table scale-free feature of an airport network, the critical value of delay propagation is extremely small, and delays are prone to propagate among airports. Furthermore, as delay propagation reaches a steady state in an aviation network, the degree value of the node becomes highly correlated with its delay state. Hub airports with high degree values are the most prone to being affected by delay propagation. In addition, the number of airports that are initially delayed influences the time required for delay propagation to reach a steady state. Specifically, if there are fewer initially delayed airports, a longer time is required to reach a steady state. In the steady state, the delay ratios of airports with different degree values in the network converge to a balance point. The delay degree of the node is highly positively correlated with the delay propagation rate in the network, but negatively related to the degree distribution index of the network.Environmental inefficiencies for arrival flights at European airportsXavier OliveJunzi SunLuis BasoraEnrico Spinielli10.1371/journal.pone.02876122023-06-23T14:00:00Z2023-06-23T14:00:00Z<p>by Xavier Olive, Junzi Sun, Luis Basora, Enrico Spinielli</p>
In this paper, we analyze two months of trajectory data for aircraft landing in five major European airports. Based on open ADS-B data from the OpenSky Network and open performance models, we enrich all trajectories with automatically detected procedure information, fuel consumption, and emissions for supported aircraft types. To assess the inefficiencies associated with holding patterns, point merges, and continuous descent operations across different airports, we propose methodologies to quantify and compare these environmental inefficiencies. Holding patterns are found to have a higher negative impact on the environment than point merge and continuous descent operations. Furthermore, the paper provides recommendations for procedure evaluations of future airports, which could help policymakers and relevant stakeholders to evaluate the environmental performances of arrival procedures based on open data and open models.What drives the decoupling progress of China’s civil aviation transportation growth from carbon emissions? A new decomposition analysisXiao LiuYancai Zhang10.1371/journal.pone.02820252023-03-06T14:00:00Z2023-03-06T14:00:00Z<p>by Xiao Liu, Yancai Zhang</p>
Civil aviation carbon emission reduction is an inevitable requirement for achieving sustainable social development. Realizing the continuous expansion of air transportation scale while reducing the impact on the environment is particularly important. Therefore, it is necessary to accurately understand the relationship between civil aviation carbon emissions and the industry development. This study established a civil-aviation-pointed Tapio decoupling model to identify the decoupling state between transportation scale added and carbon dioxide emissions in China’s civil aviation sector. The index decomposition analysis method is further applied to decompose the factors influencing the changes in decoupling states. The empirical study generated three important findings. Firstly, the overall carbon emissions in the civil aviation sector are still growing, while the energy intensity has a tendency to fluctuate and decrease. Secondly, the relationship between carbon emissions and transport turnover is dominated by the expansive coupling, that is, the development of the civil aviation sector is still at the cost of the growth of energy consumption. Nevertheless, the overall decoupling stability is unstable, and the decoupling state is likely to be changed by many external factors. Thirdly, the energy intensity decoupling effect and industry structure decoupling effect are the main reasons for civil aviation carbon decoupling. Meanwhile, the improvement of national economic level during the research period is the dominant negative factor that restrains the carbon decoupling of the civil aviation sector.A novel resilience analysis methodology for airport networks system from the perspective of different epidemic prevention and control policy responsesJiuxia GuoZongxin YangQingwei ZhongXiaoqian SunYinhai Wang10.1371/journal.pone.02819502023-02-27T14:00:00Z2023-02-27T14:00:00Z<p>by Jiuxia Guo, Zongxin Yang, Qingwei Zhong, Xiaoqian Sun, Yinhai Wang</p>
As the COVID-19 pandemic fades, the aviation industry is entering a fast recovery period. To analyze airport networks’ post-pandemic resilience during the recovery process, this paper proposes a Comprehensive Resilience Assessment (CRA) model approach using the airport networks of China, Europe, and the U.S.A as case studies. The impact of COVID-19 on the networks is analyzed after populating the models of these networks with real air traffic data. The results suggest that the pandemic has caused damage to all three networks, although the damages to the network structures of Europe and the U.S.A are more severe than the damage in China. The analysis suggests that China, as the airport network with less network performance change, has a more stable level of resilience. The analysis also shows that the different levels of stringency policy in prevention and control measures during the epidemic directly affected the recovery rate of the network. This paper provides new insights into the impact of the pandemic on airport network resilience.