Search

This research provides a current benchmark of the cognitive skills and cognitive processes needed for flight path management (FPM) in current commercial air transportation flight operations. While some cognitive skills for aviation have been identified, it remains unclear which skills are most pertinent for different phases of flight, for different tasks, across different aircraft types, and during operational complexity. Further, there is concern that flight deck automation may contribute to cognitive skill degradation. Two expert pilots participated in cognitive walkthroughs to establish a current benchmark of the cognitive skills and cognitive processes needed for FPM. The tasks involved seven different phases of flight and two different aircraft; the results from two phases are reported--Preflight Briefing and Initial Climb. The findings indicate nineteen cognitive skills, and three metacognitive skills are used by pilots for FPM. In addition, the cognitive process models needed for FPM are all very similar, regardless of the aircraft type, task, phase of flight, or increased operational complexity. These results provide a foundation for future efforts on cognitive skill degradation, training of FPM cognitive skills, and may be used to inform the design of new automated systems to support pilot cognition. [ABSTRACT FROM AUTHOR]

Urban air mobility is an effective solution to address the current issue of ground traffic congestion in future cities. However, as the user scale continues to expand, the current civil aviation flight scheduling and control methods are becoming inadequate to meet the high-volume flight guarantee demands of future urban air transportation. In order to effectively handle and resolve potential issues in this field in the future, this paper proposes a method for planning urban air mobility route networks. The planning process is divided into two stages: construction and optimization. Methods for constructing urban air mobility route networks based on flight routes and global optimization methods based on node movement are proposed in each stage. In the construction stage, a complete construction process is designed to generate routes based on existing flight routes, in line with the trend of urban air transportation development. In the optimization stage, inspired by the ant colony algorithm, node transfer rules and information transfer rules are incorporated to design a global optimization process and algorithm for route networks. Experimental results demonstrate the effectiveness and advancement of the proposed planning method. [ABSTRACT FROM AUTHOR]

In the offensive operations of the red and blue sides, in order to fully seize the battlefield air superiority, the blue side air defense fire units are usually taken as the first key targets. Therefore, it is of great significance to accurately predict the activity law of the blue side air defense fire units and scientifically design the joint reconnaissance and attack actions. Firstly, the maneuver support mode adopted by the air defense fire unit is systematically analyzed, the defense capability calculation formula is given based on the definition of defense capability, and the grid network model is introduced to complete the quantitative calculation. Based on the support scope constraint, position resource constraint and maneuver process constraint, the shortest maneuver route and the highest defense capability are taken as the optimization objectives for the actual support requirements. A prediction model for maneuvering route of ground air defense fire units is established. Secondly, aiming at the problem of solving the nonlinear model, the model linearization transformation and solving method are proposed. Then, on the basis of the optimal transfer route, an algorithm for constructing maneuver route library is designed to generate the probabilistic prediction scheme of blue side maneuver route and analyze the maneuver law of blue side air defense fire units. Finally, based on the case simulation, the feasibility and global efficiency of the designed model and method are verified, which can effectively predict the maneuvering route of blue side anti-aircraft fire units. [ABSTRACT FROM AUTHOR]

In this paper, we consider a wireless sensor network consisting of an unmanned aerial vehicle (UAV) acting as a sink node and a number of sensor nodes scattered uncertainly on the ground. In the network, the UAV flies to a spatial point called point of interest and hovers to collect environmental data from neighboring sensor nodes. Then, the UAV proceeds to the next point of interest. The UAV must gather data from all the sensor nodes. On the other hand, a shorter round-trip air route of the UAV is more preferred since a battery-operated UAV needs regular recharging. To satisfy the requirement and to adhere to the recommendation as well, especially in the situation where only vague locational information about sensor nodes is available, we propose a scheme that follows three steps. First, it covers the sensor field of the wireless sensor network with three categories of hexagonal tessellations. Secondly, it establishes a point of interest at the centroid of each tile. Thirdly, it constructs an air route of the UAV, which visits every point of interest along a Hamiltonian cycle on the induced graph. Next, we develop a closed-form expression for the exact flight distance attained by the proposed scheme. For comparative evaluation, we discover some optimal schemes that minimize the flight distance by completely inspecting all patterns and corroborating the property of Hamiltonicity. The flight distance along the air route constructed by the proposed scheme is found to be only slightly longer than the flight distance yielded by an optimal scheme. Furthermore, the proposed scheme is proven to be practically valid when a common multicopter is employed as the sink node. [ABSTRACT FROM AUTHOR]

The Ca0.6−xSr0.4HoxMnO3−δ (x = 0.05, 0.10, and 0.15) manganites with an orthorhombic crystal structure (space group Pbnm) have been produced via citrate–nitrate route in air. The electron donor holmium (Ho3+) and oxygen nonstoichiometry strongly affect the electrical conductivity (σ), Seebeck coefficient (S), thermal conductivity (κ), and thermal expansion. The increase in the absolute values of S with temperature and the decline of σ above 500 K are explained by the decrease in the concentration of Mn3+ ions due to their disproportionation into Mn2+ and Mn4+ ions. The equilibrium constant of disproportionation, the concentration and mobility of charge carriers depend on temperature and can be derived from the data for S(T) and σ(T). The formation of Mn3+ ions as a result of partial removal of oxygen from the manganites has a strong influence on their properties above 1000 K. Temperature-activated character of mobility and the values of S are consistent with the adiabatic small polaron transport mechanism in Ca0.6−xSr0.4HoxMnO3−δ. [ABSTRACT FROM AUTHOR]

A sustainable transport system is one which offers economical solutions and causes no/little damage to the environment. We usually categorize transport into three sections - roads, airways and water. Such systems need to be set up in order to have a transportation medium or ecosystem with minimum environmental impact. Public buses are an excellent example of sustainable road transportation. They can accommodate a large number of people economically and help ease the financial burden on individuals. Unfortunately, the majority of public buses are powered by non-renewable energy sources such as diesel. This results in the release of hazardous pollutants, leading to a degraded environment. Although the cost of using this form of transportation is relatively affordable, it nonetheless has an adverse effect on the environment. Therefore, it cannot be considered sustainable in that regard. We are constantly pushing the boundaries of innovation by introducing new technologies such as IoT, AI, Blockchain and 5G into our smart and sustainable transportation system. This way we can ensure its sustainability from all angles. The impact of transportation on our society is undeniable- both in terms of economic, social and environmental implications. To ensure a better quality of life for all, we must shift to smart and sustainable transport solutions. This research seeks to present a clever and eco-friendly transport system that brings economic and social advantages for developing countries. [ABSTRACT FROM AUTHOR]

The Ca0.6−xSr0.4HoxMnO3−δ (x = 0.05, 0.10, and 0.15) manganites with an orthorhombic crystal structure (space group Pbnm) have been produced via citrate–nitrate route in air. The electron donor holmium (Ho3+) and oxygen nonstoichiometry strongly affect the electrical conductivity (σ), Seebeck coefficient (S), thermal conductivity (κ), and thermal expansion. The increase in the absolute values of S with temperature and the decline of σ above 500 K are explained by the decrease in the concentration of Mn3+ ions due to their disproportionation into Mn2+ and Mn4+ ions. The equilibrium constant of disproportionation, the concentration and mobility of charge carriers depend on temperature and can be derived from the data for S(T) and σ(T). The formation of Mn3+ ions as a result of partial removal of oxygen from the manganites has a strong influence on their properties above 1000 K. Temperature-activated character of mobility and the values of S are consistent with the adiabatic small polaron transport mechanism in Ca0.6−xSr0.4HoxMnO3−δ. [ABSTRACT FROM AUTHOR]

This research aims to quantify the effect of air transport capacity on tourism demand by examining their long-term (cointegrating) relationship, accounting for cross-sectional dependence and endogeneity. Panel time series data from 2008Q1 to 2019Q4 for international tourist arrivals from 16 main origins to six Australian states are investigated. The study finds 1% increase in Available-Seat-Kilometers, seat capacity, or flight frequency can result in 0.4%–0.7% increase in tourist arrivals to Australia, adding to the body of evidence that shows a non-negligible aviation-led generative effect on tourism demand. The study finds ignoring cross-sectional dependence can result in significantly different, and potentially incorrect, coefficient estimates. Although using pre-COVID data, the results are useful in highlighting the likely aviation supply—tourism demand relations under reasonably well-performing market conditions. For greater tourism demand, findings call for more liberal international air services agreements, and direct/indirect air route development subsidies with minimum commitment of several years. [ABSTRACT FROM AUTHOR]

There is increasing adoption of cost-effective nonmetric camera-equipped unmanned aerial vehicles due to the perceived benefits of timesaving, ease of use, and the accuracy of the digital elevation models that can be produced using structure from motion software. The introduction of systematic elevation errors, doming and bowing, has been evidenced by several authors, and various methods have been identified to reduce these errors. This paper aims to analyse the impact of flight plans on these systematic errors using the especially challenging case of a corridor survey. Two sites were flown for the survey using a DJI Zenmuse. The first site, a car park, was utilised for on-the-job pre-calibration of the camera and consisted of several orbit flights and a double grip flight. Subsequently, an adjacent road (a corridor survey overall 428 m long) was also surveyed at 60 m and 80 m heights using varying flight configurations. This study confirms that pre-calibrating the camera's IOPs significantly reduces the root mean squared elevation error (from 0.268 m to 0.034 m) compared to self-calibrated IOPs using the corridor flights. The impact of flight design on elevation errors confirms a single flight path's risk and the benefits of two or more flight paths, including a point-of-interest orbit flight. [ABSTRACT FROM AUTHOR]

The installation of successional heating devices in industrial buildings will result in thermal corridors. To improve the thermal environment in and around these corridors, buoyancy-driven ventilation is commonly utilized to dissipate heat, which is based on the natural convection design for buildings. However, the flow and heat exchange patterns of natural convection related to thermal corridors have not been clearly clarified, and no relevant correlations have been established to quantify them. The conducted numerical study aimed to analyze the flow and heat transfer characteristics of natural convection within thermal corridors in industrial buildings. Experimental data were utilized to validate a computational fluid dynamics (CFD) model developed for this purpose. The study considered the influence of various parameters on the results obtained. In the side corridor, the prevalence of reverse flow dominates much of the channel, while in the middle corridor, reverse flow near the bottom corner is observed. The ambient air temperature significantly impacts the temperature distribution in both corridors. Increasing the ambient air temperature at the inlet from 22 to 28 °C results in a substantial temperature rise within the corridor, by approximately 6–7 °C. When the outlet size is constant and the inlet size drops by 30%, the air temperature in the corridor increases by 3 °C. Finally, correlations were established based on the simulation data to predict the surface-averaged N u ¯ of the heated wall and the induced mass flow rate, m ˙ , of the natural convection. The correlations have relative errors of less than 16% when compared to the simulation data. [ABSTRACT FROM AUTHOR]

The article considers the application of the analysis method using graph theory to determine critical points in the air networks of Ukraine, Turkey and Moldova. The goal is to identify critical points in the above-mentioned aerial networks. The reason is the probability of resuming air traffic between Ukraine and neighboring countries (with the exception of the Russian Federation). The data on the network is obtained from collections of aeronautical information. Modeling was performed in the Python software environment using libraries for processing and visualizing the received data. The main criteria used to determine the criticality of a radio navigation point are Betweenness centrality and Closeness centrality. In addition, the collection and comparison of statistical data on the number of routes and radio navigation points in each of the studied countries will be performed. The obtained data are useful, because it will give an opportunity to compare the results with those obtained during the study of the Ukrainian network and for air navigation service providers to improve the existing network. [ABSTRACT FROM AUTHOR]

To fully leverage the spatiotemporal dynamic correlations in air traffic flow and enhance the accuracy of traffic flow prediction models, thereby providing a more precise basis for perceiving congestion situations in the air route network, a study was conducted on a traffic flow prediction method based on deep learning considering spatiotemporal factors. A waypoint network topology graph was constructed, and a neural network model called graph convolution and self-attention-based long short-term memory neural network (GC-SALSTM) was proposed. This model utilized waypoint flow and network efficiency loss rate as input features, with graph convolution extracting spatial features from the waypoint network. Additionally, a long short-term memory network based on a self-attention mechanism was used to extract temporal features, achieving accurate prediction of waypoint traffic. An example analysis was performed on a typical busy sector of airports in the Central and Southern China region. The effectiveness of adding the network efficiency loss rate as an input feature to improve the accuracy of critical waypoint traffic prediction was validated. The performance of the proposed model was compared with various typical prediction models. The results indicated that, with the addition of the network efficiency loss rate, the root mean square error (RMSE) for eight waypoints decreased by more than 10%. Compared to the historical average (HA), autoregressive integrated moving average (ARIMA), support vector regression (SVR), long short-term memory (LSTM), and graph convolution network and long short-term memory network (GCN-LSTM) models, the RMSE of the proposed model decreased by 11.78%, 5.55%, 0.29%, 2.53%, and 1.09%, respectively. This suggests that the adopted network efficiency loss rate indicator effectively enhances prediction accuracy, and the constructed model exhibits superior predictive performance in short-term waypoint traffic forecasting compared to other prediction models. It contributes to optimizing flight paths and high-altitude air routes, minimizing flight delays and airborne congestion to the greatest extent, thus enhancing the overall efficiency of the entire aviation system. [ABSTRACT FROM AUTHOR]

The BIO-MAÏDO (Bio-physicochemistry of tropical clouds at Maïdo: processes and impacts on secondary organic aerosols formation) campaign was conducted from 13 March to 4 April 2019 on the tropical island of Réunion. The main objective of the project was to improve understanding of cloud impacts on the formation of secondary organic aerosols (SOA) from biogenic volatile organic compound (BVOC) precursors in a tropical environment. Instruments were deployed at five sites: a receptor site, Maïdo Observatory (MO) at 2165 m a.s.l. and four sites along the slope of the Maïdo mountain. Observations include measurements of volatile organic compounds (VOCs) and characterization of the physical, chemical and biological (bacterial diversity and culture-based approaches) properties of aerosols and cloud water. Turbulent parameters of the boundary layer, radiative fluxes and emissions fluxes of BVOCs from the surrounding vegetation were measured to help interpret observed chemical concentrations in the different phases. Dynamical analyses showed two preferred trajectory routes for air masses arriving at MO during the daytime. Both trajectories correspond to return branches of the trade winds associated with upslope thermal breezes, where air masses likely encountered cloud processing. The highest mixing ratios of oxygenated VOCs (OVOCs) were measured above the site located in the endemic forest and the highest contribution of OVOCs to total VOCs at MO. Chemical compositions of particles during daytime showed higher concentrations of oxalic acid, a tracer of cloud processing and photochemical aging, and a more oxidized organic aerosol at MO than at other sites. Approximately 20 % of the dissolved organic compounds were analyzed. Additional analyses by ultra-high-resolution mass spectrometry will explore the complexity of the missing cloud organic matter. [ABSTRACT FROM AUTHOR]

This paper examines the effect of bilateral air connectivity on bilateral service trade flows. Our service trade data includes 'commercial', 'transport', 'travel', and 'government' services. We developed a reduced-form gravity-type model using the Chinese data. An instrument variable (IV) approach is adopted to address the endogeneity issue between bilateral air connectivity and the service trade variables. Our key results are: (a) increasing the number of direct routes can significantly promote bilateral service export and import trades; (b) the average route-level traffic density has only marginal positive effects; (c) improving air connectivity would enlarge China's overall service trade deficit, because the transport and travel services imports are promoted more than their exports; (d) The 'commercial' service exports can be stimulated more than the imports, making China achieve larger commercial service trade surplus by improving bilateral air connectivity. •Increasing the number of direct air routes significantly promotes bilateral service trades in China. •Improving air connectivity enlarges China's overall service trade deficit. •Enhancing bilateral air connectivity stimulates China's commercial service exports more than imports. •China's growing international air transport, facilitated by the Belt-and-Road Initiative, has had a substantial impact on bilateral service trade. [ABSTRACT FROM AUTHOR]

Uncrewed aircraft systems (UAS), also known as drones, have become increasingly popular in various applications due to their ability to access remote or challenging locations. A crucial aspect of UAS operations is flight path planning, which determines the trajectory the aircraft takes to achieve its mission objectives. However, the diverse use cases of UAS demand different planning approaches tailored to their specific requirements. This paper presents an overview over current research in UAS flight path planning and proposes a categorization of use cases based on their distinct goals and considerations. The terminology differentiates the goals of tasks between navigation-centric and data acquisition and also considers their context, domain, perspective, and sensors. We analyze existing approaches with a focus on UAS flight path planning for data acquisition using cameras, highlighting their strengths and limitations. This structured overview facilitates the understanding of the diverse landscape of UAS flight path planning and paves the way for the development of more targeted and effective solutions for various applications and their use cases. The analysis shows, that the term "UAS flight path planning" is currently used in a variety of distinct use cases with diverging requirements, so a unified terminology should be established for clear communication. [ABSTRACT FROM AUTHOR]

Two severe dust storm (DS) events (15–17 March and 28–29 March) hit northern China in 2021 consecutively. The lower atmospheric vertical dynamic and thermal structures during the two cases were compared using the ground-based sensor data from the microwave radiometer and radar wind profiler, combined with the environmental and meteorological observations data in Jinan, China. It was found that both cases occurred under the background of cold vortexes over northeastern China. The dust was transported through the cold air on the northwest route. During the dust period, 2–3 km was the west or northwest airflow, and below 2 km was the northeast wind. The variation in the dynamic structure determined the duration of the DS. During the DS maintenance phase, the vertical wind shear (VWS) below 3 km measured approximately 10 m∙(s∙km)−1. The increased VWS during the dust intrusion period facilitated the transportation of dust. In contrast, the more significant VWS was not conducive to the maintenance of DS, and the shift to south wind control in the upper middle layer indicated the weakening of DS. In both cases, we observed a cliff-like decrease in relative humidity as a prominent indicator of dust outbreaks, occurring approximately 2–5 h beforehand. The diurnal difference between the vertical temperature and relative humidity during the dust maintenance period was found to be insignificant. [ABSTRACT FROM AUTHOR]

Seve Ballesteros-Santander Airport (SDR/LEXJ) is a success story among Europe's small regional airports. This success is due, among other factors, to: 1) the commitment to the promotion of connectivity and tourism by the successive regional governments of Cantabria, one of the 17 regions making up Spain; 2) the management of the infrastructure carried out by Aena, with intense modernisation and expansion of the airport; and 3) the commitment of the airlines to Cantabria through the development of a large network of air routes, especially Ryanair, but also Air Nostrum, Vueling, Iberia, Volotea, Wizz Air and Binter. In the last 20 years, the airport's traffic volume has quadrupled from 250.000 passengers to one million. The number of destinations has increased from just a few frequencies to Madrid and Barcelona to 30 destinations covering the whole of Spain and providing connectivity to the main European capitals and major cities. This paper will analyse some of the factors, including supply and demand, that have given rise to this success. It will also discuss the economic impact of the airport on the region and some of the main opportunities and challenges it will face throughout the coming years. [ABSTRACT FROM AUTHOR]

The assessment of collision risk at intersecting air routes is a crucial method for determining safe separation during aircraft route flights. This paper employs the Monte Carlo method to analyze the operational characteristics of aircraft on intersecting air routes in two stages, integrating the influence of the human-operated adjustment process on the distance between the two aircrafts, so as to propose a collision risk assessment model more aligned with the actual operational process. The initial stage considers the positional errors to establish a distance distribution function between trailing and leading aircraft when the latter reaches the intersection. The subsequent stage calculates the minimum distance between the aircraft by combining the kinematic equations with the controller's thinking and reactions, communications, the pilot's reactivity, and time required for aircraft maneuvering. Ultimately, based on the intersection course configuration, Monte Carlo simulations were employed to assess the impact of variables, such as magnetic course and aircraft speed distribution, on collision risk. The study's findings highlight the significance of aircraft positioning capabilities and speed maintenance performance. It also reveals that the collision risk results, simulated from various perspectives, offer a theoretical foundation for the development of intersecting air routes. [ABSTRACT FROM AUTHOR]

Both cruising ability and safety should be considered in the 3D inspection path planning of agricultural unmanned aerial vehicles (UAVs). Specific to a complex working environment, the 3D inspection environment of agricultural UAVs was simulated through terrain modeling and threat modeling. First, the dynamic constraints of flight approaching rate and response time were added to the threat cost, and the 3D mission space model and flight path cost function were constructed considering the influence of UAVs' turning performance. Second, the offset estimation strategy, variable spiral search strategy, quasi-reverse learning strategy and dimension-by-dimension mutation strategy were introduced into the dung beetle optimizer (DBO) algorithm to improve the global optimization ability and convergence rate of the algorithm. By establishing a three-dimensional trajectory planning model for unmanned aerial vehicles, the trajectory planning is transformed into a multi-objective function optimization problem, and an improved algorithm is used to solve the three-dimensional trajectory planning of unmanned aerial vehicles. The fitness is evaluated by considering the objective function of trajectory cost, terrain cost, and danger level, and the trajectory planning is iteratively optimized. The results indicate that the proposed improved dung beetle algorithm for trajectory planning has lower overall cost and stability in adapting to different complex terrain environments. [ABSTRACT FROM AUTHOR]

The global navigation satellite system (GNSS) signals are vulnerable to disruption sources, such as signal jamming. This, in turn, can cause severe degradation or discontinuities of the GNSS-based position, navigation, and timing services. The availability of multi-frequency signals from multi-constellation GNSS systems, such as Galileo and GLONASS, along with the modernization of GPS with multi-frequency signals, has the potential to increase the immunity of GNSS-based navigation systems to signal jamming. Despite various studies completed on the utilization of multi-frequency and multi-constellation global navigation satellite system (GNSS) signals to resist receiver jamming, there is still an urge to further investigate this concern under different circumstances. This paper presents an experimental evaluation of the advantages of the employment of multi-frequency multi-constellation GNSS signals for better GNSS receivers' performance during signal jamming situations for high-dynamic platforms such as aircraft/drones. Additionally, the study examines the effects of both simulated and real jamming signals on all possible combinations of the GPS, Galileo, and GLONASS signal frequencies and constellations. Two airplane trajectory routes were built, and their corresponding RF signals were generated using the Spirent and Orolia GNSS signal simulators. The results indicated that the GPS multi-frequency-based solution maintains reliable positioning performance to some extent under low jamming scenarios. However, the combination of GPS, Galileo, and GLONASS signals proved its ability to provide a continuous and accurate positioning solution during both low and high jamming scenarios. [ABSTRACT FROM AUTHOR]

Biochar always suffers from low porosity and/or poor surface functionality, which limit its performances. Among various surface engineering strategies, air oxidation favors both pore development and surface oxygenation for biochar. However, there is still a lack of systematic knowledge and critical perspective on air oxidation in surface engineering of biochar-based materials for various applications. Herein, this review analyzed the mechanisms of air oxidation, summarized the routes of air oxidation in surface engineering of biochar-based materials, investigated the impacts of controlling factors (including operation parameters and intrinsic biochar structure) on pore development and surface oxygenation during air oxidation, and discussed the performances of the resultant materials in pollution control, biomass catalytic conversion and energy storage. This review suggested that air oxidation could be conducted in oxidative torrefaction/pyrolysis, and applied as post-modification or pretreatment processes. Interestingly, air oxidation is efficient in enriching the heteroatoms in the heteroatom-doped biochar, and promoting the doping of metal species on biochar by enriching the anchor sites. This review also highlighted the future challenges concerning air oxidation in the surface engineering of biochar-based materials. Finally, this review was intended to attract broad attention and inspire new discoveries for promoting the application of air oxidation in surface engineering of biochar-based materials for various advanced applications. Highlights: • Air oxidation favors pore development and/or surface oxygenation for biochar. • Air oxidation can be conducted in oxidative torrefaction/pyrolysis, and applied as post-modification or pretreatment processes. • Mechanisms and controlling factors for air oxidation were analyzed, and future challenges were highlighted. [ABSTRACT FROM AUTHOR]

High performance carbon containing castables have always been pursued by researchers and steelmaking producers, unfortunately, poor water‐wettability of graphite flakes was greatly limited their application in castables. To respond this, we proposed a large‐scale and low‐cost modified molten salt shielding synthesis technique for fabricating TiC coated graphite in air atmosphere using graphite flake and Ti powder as raw materials. Microstructure, wettability and oxidation resistance of TiC@C powders, and effect of TiC@C powders on the properties of Al2O3‐MgO‐C castables were investigated. The results demonstrate that TiC coated graphite was synthesized via modified molten salt shielding synthesis route in air atmosphere. A uniform and continuous TiC layer was formed on the surface of graphite, thereby significantly improving the water‐wettability and oxidation resistance of graphite flakes. The castables with 5% TiC@C powders possessed lower apparent porosity, higher cold strength, good oxidation resistance, and slag resistance in comparison with the castables with graphite flakes, and slag resistance were also better than Al2O3‐MgO castables. The as‐fabricated TiC@C powders have good water‐wettability and oxidation resistance, making them as a prime carbon source for producing carbon containing castables for steel ladle linings. [ABSTRACT FROM AUTHOR]

With the EU regulation of drone operations varying based on the specific type of drone, path planning can be done to consider risk mitigation. This paper proposes a transition-based rapidly exploring random tree star (T-RRT*) path planning algorithm for fixed-wing drone operations over rural areas. Risk is decoded in the cost function, which mainly considers population density and special infrastructure types. It was found that the algorithm is capable of finding paths that minimize exposure of the general population and infrastructure. However, path and computational inefficiencies were found. Usage of another data structure or algorithm might improve performance. [ABSTRACT FROM AUTHOR]

This study investigates the effect of dread and unknown risks on individuals' cognitive and affective responses and decision-making related to particulate matter (PM) air pollution. In particular, we investigate how dread and unknown risks play different roles in forming the cognitive and affective routes that affect the South Korean public's intentions to reduce PM air pollution by adopting risk mitigation behaviors. One thousand South Korean adults participated in the study via a professional research company in 2022. Statistical analysis was performed using PROCESS Marco. Indirect effects and their significance were estimated using bias-corrected bootstrap (n = 5,000 resampling) confidence intervals (CIs). According to the results, perceived dread of PM air pollution had significant and positive associations with perceived health risks and negative emotion, and perceived risks had a significant and positive association with negative emotion. Moreover, the perceived unknown-ness of PM air pollution had a significant and positive association with perceived uncertainty, which had a significant and negative association with negative emotion. Our mediation models demonstrate that the cognitive and affective routes associated with the two risk dimensions had different effects on behavioral intentions to reduce PM air pollution. These distinct cognitive and affective routes have significant theoretical implications for the effective application of the psychometric paradigm in addressing various risk-related issues. The findings also imply that an appropriate level of negative emotion is crucial to motivate the public's engagement in risk-reduction behaviors. While employing campaign messages that integrate perceived risk and negative emotional appeals derived from dread can be effective, caution should be taken not to diminish the public's negative emotions when addressing the risk-related uncertainty in campaigns or interventions. Overall, our findings not only have several practical implications for environmental communication strategies but also make important theoretical contributions to the literature on risk perceptions and the psychometric paradigm. [ABSTRACT FROM AUTHOR]

The topological structure of the world air transportation network has been the subject of much research. However, to better understand the reality of air networks, one can consider the traffic, the number of passengers, or the distance between flights. This paper studies the weighted world air transportation network through the component structure, recently introduced in the network literature, by using the number of flights. The component structure is based on the community or multiple core-periphery structures and splits the network into local and global components. The local components capture the regional flights of these two mesoscopic structures (dense parts). The global components capture the inter-regional flights (links between the dense parts). We perform a comparative analysis of the world air transportation network and its components with their weighted counterparts. Moreover, we explore the strength and the s-core of these networks. Results display fewer local components well delimited and more global components covering the world than the unweighted world air transportation network. Centrality analysis reveals the difference between the top airports with high traffic and the top airports with high degrees. This difference is more pronounced in the global air network and the largest global component. Core analysis shows similitude between the s-core and the k-core for the local and global components, even though the latter includes more airports. For the world air network, the North and Central America-Caribbean airports dominate the s-core, whereas the European airports dominate the k-core. [ABSTRACT FROM AUTHOR]

In the current accelerated process of global warming, forest conservation is becoming more difficult to address in developing countries, where woodlands are often fueling the illegal economy. In Colombia, the issue of narcodeforestation is of great concern, because of the ramification of narcoactivities that are affecting forests, such as agribusinesses and cattle ranching for money laundering. In this study, we use spatially explicit regressions incorporating a factor decomposition of predictors through principal component analysis to understand the impact of coca plantations on global and local-scale deforestation in Colombia. At national level we find a positive and statistically significant relationship between coca crops and deforestation. At the regional level, in two out of four regions, it appears that coca is causing deforestation, especially in the Department of Northern Santander and on the Pacific coast. The spatial models used reveal not only a direct effect but also positive and significant spillover effects, in line with the conjecture that narcodeforestation is not only due to the quest for new areas to expand coca-cultivation, which would determine a loss of forest only in the municipality where coca cultivation increases, but also to the need to launder illegal profits, or create clandestine routes and airplane strips, which can affect forests also in nearby municipalities. [ABSTRACT FROM AUTHOR]

A 19-year-old with blunt trauma and repeated nose blowing presented with orbital emphysema and orbital compartment syndrome. Orbital emphysema is the abnormal presence of air within the orbit, typically secondary to trauma. Most cases will resolve with observation alone, however orbital compartment syndrome is a feared complication that necessitates urgent decompression. A superior fornix, trans-conjunctival approach was safely utilized to decompress the orbit while avoiding unwanted complications. Various decompression techniques have previously been described, most of which describe trans-palpebral approaches. The key safety benefit to the trans-conjunctival approach is direct visualization of the needle tip adjacent to the superior fornix, therefore posterior to the equator of the globe. With the needle positioned parallel to the curvature of the globe at the equator, the posterior sclera surface curves away from the tip, rendering it difficult to pierce the globe. In addition, the needle needs to be advanced only 3–4 millimeters and traverses only the conjunctiva and Tenon's to enter the central surgical space – the most direct route to the air pocket. The trans-conjunctival approach lowers the risk of damage to eyelid neurovascular structures and is less painful. [ABSTRACT FROM AUTHOR]

The BIO-MAÏDO (Bio-physicochemistry of tropical clouds at Maïdo (Réunion Island): processes and impacts on secondary organic aerosols formation) campaign was conducted from the 13th of March to the 4th of April 2019 on the tropical Réunion Island and implied several scientific teams and state-of-the-art instrumentation. The campaign was part of the BIO-MAÏDO project with the main objective is to improve our understanding of cloud impacts on the formation of secondary organic aerosols (SOA) from biogenic volatile organic compounds (BVOC) precursors in a tropical environment. Instruments were deployed at five sites: a receptor site, the Maïdo observatory (MO) at 2165 m asl, and four sites along the slope of the Maïdo mountain. The obtained dataset includes measurements of the gas-phase mixing ratio of volatile organic compounds (VOC), the characterization of the physical, chemical, and biological (bacterial diversity) properties of aerosols and the characterization of the physical, chemical and biological (identification of viable bacteria through culture-based approaches) properties of the cloud water. In addition, the turbulent parameters of the boundary layer, radiative fluxes, and emissions fluxes of BVOC from the surrounding vegetation were measured to help with the interpretation of the observed chemical concentrations in the different phases. Dynamical analyses show two preferred trajectories routes for air masses arriving at MO during the daytime both corresponding to the return branches of the trade winds associated with the up-slopes thermal breezes. These air masses likely encountered cloud processing during transport along the slope. The highest mixing ratio of oxygenated VOC (OVOC) were measured above the site located in the endemic forest and the highest contribution of OVOC to total VOC at MO. Chemical composition of particles during the daytime shows a higher concentration of oxalic acid and a more oxidized organic aerosol at MO than at other sites along the slope. This is a signature of photochemical aerosols aging along the slope potentially influenced by cloud processing. Despite an in-depth analysis of organic compounds in cloud water, around 80 % on average of dissolved organic compounds is undefined highlighting the complexity of the cloud organic matter. [ABSTRACT FROM AUTHOR]

The traveling salesman problem (TSP) is a very popular combinatorics problem. This problem has been widely applied to various real problems. The TSP problem has been classified as a Non-deterministic Polynomial Hard (NP-Hard), so a non-deterministic algorithm is needed to solve this problem. However, a non-deterministic algorithm can only produce a fairly good solution but does not guarantee an optimal solution. Therefore, there are still opportunities to develop new algorithms with better optimization results. This research develops a new algorithm by hybridizing three local search algorithms, namely, iterated local search (ILS) with simulated annealing (SA) and hill climbing (HC), to get a better optimization result. This algorithm aimed to solve TSP problems in the transportation sector, using a case study from the Traveling Salesman Challenge 2.0 (TSC 2.0). The test results show that the developed algorithm can optimize better by 15.7% on average and 11.4% based on the best results compared to previous studies using the Tabu-SA algorithm. [ABSTRACT FROM AUTHOR]

Application of formation flights to civil aviation is gaining interest, primarily due to the fuel burn reduction achieved by flying through another aircraft's wake. However, it is emerging that there are additional, less‐recognized climate benefits via reduction in ozone and contrail warming through this concept. The NOx threshold level is defined as when the loss rate for OH by reaction with NO2 is equal to the loss rates for OH with CO and CH4, beyond which level, ozone formation will decrease. In this study, The NOx threshold level was calculated at different altitudes and found that at cruise altitude (∼10 km), the amount of NO2 required for parity in OH loss with loss due to reaction with CO and CH4 is around 2 ppb. The spatial and temporal NOx threshold levels were estimated by STOCHEM‐Common Representative Intermediate (CRI) global chemical transport model and In‐service Aircraft for Global Observing System (IAGOS) measurement data and found that northern midlatitudes of the atmosphere are the most favorable region existing with the smallest NOx thresholds (0.5 ppb) needed before reduction in ozone formation is likely to occur at cruise altitude of aircraft. Incorporating the major air traffic corridors into the coarse spatial resolution of the chemical transport model overestimated the NOx compensation point, that is, increased photochemical ozone production. Thus, a simple one‐dimensional (1D) aircraft plume dispersion model was developed with higher spatial and temporal resolution for considering aircraft plumes and its chemistry more accurately. The model run shows that the impact of formation flying aircraft emissions on spatially averaged ozone could be halved if the aircraft could maintain separations inside 4 km relative to well separated flights of 10 km or more. [ABSTRACT FROM AUTHOR]

In this paper, a network coupling mechanism is studied to couple the air sector network, airport network, and air route network into a multilayer air network model. Then, the altitude layers are divided into three: high, medium, and low, and the arrival and departure flight procedures are also considered. By defining the association between the altitude layers and the waypoints, a multilayer air network model considering the altitude layer is constructed. Then, the line graph theory is used to redefine the nodes and edges, and the network is reconstructed to obtain a new single-layer one which is easy to calculate. Finally, a case study is carried out in Chengdu control area. The results show that the proposed model is closer to the reality, and the invulnerability performance is more referential. Besides, it also reflects the impact of altitude layers on the efficiency of airspace. The results are helpful for air traffic controllers to manage airspace better and have significance for promoting air traffic safety and stability. [ABSTRACT FROM AUTHOR]