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Topic Review
Air Mass
In astronomy, air mass or airmass is a measure of the amount of air along the line of sight when observing a star or other celestial source from below Earth's atmosphere (Green 1992). It is formulated as the integral of air density along the light ray. As it penetrates the atmosphere, light is attenuated by scattering and absorption; the thicker atmosphere through which it passes, the greater the attenuation. Consequently, celestial bodies when nearer the horizon appear less bright than when nearer the zenith. This attenuation, known as atmospheric extinction, is described quantitatively by the Beer–Lambert law. "Air mass" normally indicates relative air mass, the ratio of absolute air masses (as defined above) at oblique incidence relative to that at zenith. So, by definition, the relative air mass at the zenith is 1. Air mass increases as the angle between the source and the zenith increases, reaching a value of approximately 38 at the horizon. Air mass can be less than one at an elevation greater than sea level; however, most closed-form expressions for air mass do not include the effects of the observer's elevation, so adjustment must usually be accomplished by other means. Tables of air mass have been published by numerous authors, including Bemporad (1904), Allen (1976), and Kasten and Young (1989).
  • 1.8K
  • 11 Oct 2022
Topic Review Peer Reviewed
Aircraft Icing Severity Evaluation
Aircraft icing refers to the ice buildup on the surface of an aircraft flying in icing conditions. The ice accretion on the aircraft alters the original aerodynamic configuration and degrades the aerodynamic performances and may lead to unsafe flight conditions. Evaluating the flow structure, icing mechanism and consequences is of great importance to the development of an anti/deicing technique. Studies have shown computational fluid dynamics (CFD) and machine learning (ML) to be effective in predicting the ice shape and icing severity under different flight conditions. CFD solves a set of partial differential equations to obtain the air flow fields, water droplets trajectories and ice shape. ML is a branch of artificial intelligence and, based on the data, the self-improved computer algorithms can be effective in finding the nonlinear mapping relationship between the input flight conditions and the output aircraft icing severity features.
  • 1.3K
  • 13 Apr 2022
Topic Review
Airframe In-Service Pitting Corrosion
Pitting corrosion is a major maintenance problem for aircraft aluminium alloys, and is also a problem for other materials. It has been considered that some service examples of corrosion-induced pitting or cracks exposed to service environments. These examples support the contention that fatigue crack growth, which is mainly due to in-flight dynamic loads, is not significantly influenced by the environment, unlike the largely static exposure on the ground.
  • 491
  • 22 Jun 2022
Topic Review
Alternative Aviation Fuels/Pathways
The Paris Agreement’s objectives related to climate change put aviation under great pressure and environmental inspection. In particular, the aviation industry is committed to achieving a 50% reduction in CO2 emissions by 2050 compared to 2005 levels. A shift to alternative aviation fuels seems imperative. The International Air Transport Association (IATA) has identified the production of drop-in sustainable liquid fuels (SAFs) as the most promising strategy, at least short term, to reduce the environmental impact of the sector.
  • 942
  • 03 Mar 2023
Topic Review
Applications of Sustainable Hybrid Energy Harvesting
The potential usage of self-powered wireless sensor (WSN) systems has drawn a lot of attention to sustainable energy harvesting. Hybrid energy harvesting involves collecting energy from multiple sources and converting it into electrical energy using various transduction mechanisms. By properly integrating different energy conversion technologies, hybridization can significantly increase power outputs and improve space utilization efficiency.
  • 410
  • 28 Nov 2023
Topic Review
Applications of Unmanned Aerial Vehicles
Unmanned aerial vehicles (UAVs), also known as drones, have come in a great diversity of several applications such as military, construction, image and video mapping, medical, search and rescue, parcel delivery, hidden area exploration, oil rigs and power line monitoring, precision farming, wireless communication and aerial surveillance. The drone industry has been getting significant attention as a model of manufacturing, service and delivery convergence, introducing synergy with the coexistence of different emerging domains. 
  • 19.8K
  • 27 Jul 2022
Topic Review
Applications of Unmanned Aerial Vehicles during COVID-19
Unmanned aerial vehicles (UAVs), also referred to as drones, have received momentous attention in various domains of civil and military operations because of their high mobility, enhanced stability, low cost, and high endurance in multiple tasks.
  • 766
  • 21 Oct 2022
Topic Review
Ariane Flight VA241
Ariane flight VA241 was an Ariane 5 space launch that occurred from the Guiana Space Centre on 25 January 2018 at 22:20 UTC.
  • 264
  • 14 Oct 2022
Topic Review
Artificial Intelligence in Aviation: NextGen for NextTech
The rapid advancement and adoption of artificial intelligence technologies are fundamentally transforming the landscape of the aviation industry. From flight planning to aircraft maintenance, AI-driven tools like machine learning, natural language processing, and computer vision are being integrated across nearly every aspect of modern aviation. While AI innovation holds great promise for augmenting human capabilities and enhancing safety and efficiency, it also poses new challenges for aviation education and training. This paradigm shift requires aviation professionals to possess competencies in emerging technologies and their applications in order to be effective in increasingly AI-mediated work environments. An analytical methodology and competency framework is provided to help educators address this gap. Producing graduates equipped with AI literacy and collaboration skills will be key to aviation’s intelligent future.
  • 213
  • 24 Nov 2023
Topic Review
Astrophotography
Astrophotography, also known as astronomical imaging, is the photography or imaging of astronomical objects, celestial events, or areas of the night sky. The first photograph of an astronomical object (the Moon) was taken in 1840, but it was not until the late 19th century that advances in technology allowed for detailed stellar photography. Besides being able to record the details of extended objects such as the Moon, Sun, and planets, modern astrophotography has the ability to image objects invisible to the human eye such as dim stars, nebulae, and galaxies. This is done by long time exposure since both film and digital cameras can accumulate and sum photons over these long periods of time. Photography using extended exposure-times revolutionized the field of professional astronomical research, recording hundreds of thousands of new stars, and nebulae invisible to the human eye. Specialized and ever-larger optical telescopes were constructed as essentially big cameras to record images on photographic plates. Astrophotography had an early role in sky surveys and star classification but over time it has given way to more sophisticated equipment and techniques designed for specific fields of scientific research, with image sensors becoming just one of many forms of sensor. Today, astrophotography is mostly a subdiscipline in amateur astronomy, usually seeking aesthetically pleasing images rather than scientific data. Amateurs use a wide range of special equipment and techniques.
  • 1.6K
  • 22 Nov 2022
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