The Experts below are selected from a list of 1932 Experts worldwide ranked by ideXlab platform
Calvin B. Sawyer - One of the best experts on this subject based on the ideXlab platform.
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Autonomous In Situ Measurements of Noncontaminant Water Quality Indicators and Sample Collection with a UAV
Water, 2019Co-Authors: Cengiz Koparan, A. B. Koc, Charles V. Privette, Calvin B. SawyerAbstract:The objective of this research was to conduct in situ measurements of electrical conductivity (EC), pH, dissolved oxygen (DO), and temperature, and collect water samples simultaneously at different depths using an unmanned aerial vehicle (UAV). The UAV system consists of a hexacopter, water sampling cartridges (WSC), and a sensor node. Payload capacity and endurance of the UAV were determined using an indoor test station. The UAV was able to produce 106 N of thrust for 10 min with 6.3 kg of total Takeoff Weight. The thrust-to-Weight ratio of the UAV was 2.5 at 50% throttle. The decision for activating the water sampling cartridges and sensor node was made autonomously from an onboard microcontroller. System functions were verified at 0.5 m and 3.0 m depths in 6 locations over a 1.1 ha agricultural pond. Average measurements of EC, pH, DO, and temperature at 0.5 m depth were 42 µS/cm, 5.6, 8.2 mg/L, and 31 °C, while the measurements at 3 m depth were 80 µS/cm, 5.3, 5.34 mg/L, and 24 °C, respectively. The UAV-assisted autonomous water sampling system (UASS) successfully activated the WSC at each sampling location. The UASS would reduce the duration of water quality assessment and help practitioners and researchers to conduct observations with lower operational costs. The developed system would be useful for sampling and monitoring of water reservoirs, lakes, rivers, and ponds periodically or after natural disasters.
Holzäpfel Frank - One of the best experts on this subject based on the ideXlab platform.
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Wake Turbulence Evolution and Hazard Analysis for General Aviation Takeoff Accident
'American Institute of Aeronautics and Astronautics (AIAA)', 2019Co-Authors: Schwarz Carsten, Fischenberg Dietrich, Holzäpfel FrankAbstract:Wake turbulence is commonly a commercial aviation topic involving relatively heavy transport aircraft. However, wake turbulence is also safety relevant for business and general aviation flight operations. A detailed analysis has been conducted for a specific accident involving two aircraft of the wake turbulence category light. A four-seat aircraft with 1 ton maximum Takeoff Weight took off behind a biplane with 5.5 ton maximum Takeoff Weight. This led to a fatal accident. Based on available information and several assumptions, the wake turbulence aspects for the specific accident scenario have been assessed. The roll axis was the dominating factor in this case. Accordingly, the wake induced rolling moment was analyzed and related to the assumed available roll control power. Furthermore, the wake vortex behavior was simulated and analyzed in detail. The results indicate that wake turbulence can be considered to be the cause of the accident. The theoretical results and the conclusions regarding the accident are also supported by the results of flight tests, which were conducted in the context of the accident Investigation
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Wake Turbulence Evolution and Hazard Analysis for a General Aviation Takeoff Accident
'American Institute of Aeronautics and Astronautics (AIAA)', 2018Co-Authors: Schwarz Carsten, Fischenberg Dietrich, Holzäpfel FrankAbstract:Wake turbulence is commonly a commercial aviation topic involving relatively heavy transport aircraft. However, wake turbulence is also safety relevant for business and general aviation flight operations. A detailed analysis has been conducted for a specific accident involving two aircraft of the wake turbulence category light. A four-seat aircraft with one ton maximum Takeoff Weight took off behind a biplane with 5.5 tons maximum Takeoff Weight. This led to a fatal accident. Based on available information and several assumptions the wake turbulence aspects for the specific accident scenario have been assessed. The roll axis was the dominating factor in this case. Accordingly, the wake induced rolling moment was analyzed and related to the assumed available roll control power. Furthermore, the wake vortex behavior was simulated and analyzed in detail. The results indicate that wake turbulence can be considered to be the cause for the accident. The theoretical results and the conclusions regarding the accident are also supported by the results of flight tests, which were conducted in the context of the accident investigation
Cengiz Koparan - One of the best experts on this subject based on the ideXlab platform.
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Autonomous In Situ Measurements of Noncontaminant Water Quality Indicators and Sample Collection with a UAV
Water, 2019Co-Authors: Cengiz Koparan, A. B. Koc, Charles V. Privette, Calvin B. SawyerAbstract:The objective of this research was to conduct in situ measurements of electrical conductivity (EC), pH, dissolved oxygen (DO), and temperature, and collect water samples simultaneously at different depths using an unmanned aerial vehicle (UAV). The UAV system consists of a hexacopter, water sampling cartridges (WSC), and a sensor node. Payload capacity and endurance of the UAV were determined using an indoor test station. The UAV was able to produce 106 N of thrust for 10 min with 6.3 kg of total Takeoff Weight. The thrust-to-Weight ratio of the UAV was 2.5 at 50% throttle. The decision for activating the water sampling cartridges and sensor node was made autonomously from an onboard microcontroller. System functions were verified at 0.5 m and 3.0 m depths in 6 locations over a 1.1 ha agricultural pond. Average measurements of EC, pH, DO, and temperature at 0.5 m depth were 42 µS/cm, 5.6, 8.2 mg/L, and 31 °C, while the measurements at 3 m depth were 80 µS/cm, 5.3, 5.34 mg/L, and 24 °C, respectively. The UAV-assisted autonomous water sampling system (UASS) successfully activated the WSC at each sampling location. The UASS would reduce the duration of water quality assessment and help practitioners and researchers to conduct observations with lower operational costs. The developed system would be useful for sampling and monitoring of water reservoirs, lakes, rivers, and ponds periodically or after natural disasters.
Jingwen Lu - One of the best experts on this subject based on the ideXlab platform.
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Impact of 1.5 °C and 2.0 °C global warming on aircraft Takeoff performance in China
Science Bulletin, 2018Co-Authors: Tianjun Zhou, Liwen Ren, Haiwen Liu, Jingwen LuAbstract:Associated with global warming, climate extremes such as extreme temperature will significantly increase. Understanding how climate change will impact the airflights is important to the planning of future flight operations. In this study, the impacts of 1.5 and 2 degree's global warming on the aircraft Takeoff performance in China are investigated using a unique climate projection data from an international collaboration project named HAPPI. It is found that the mean summer daily maximum temperature, which is a major factor that affects the flight through changing the aircraft's Takeoff Weight, will increase significantly with magnitude less than 1.5 °C over most parts of China except for the Tibetan Plateau. The half a degree additional global warming will lead to higher extreme temperature in the arid and semi-arid western China, the Tibetan Plateau and the northeastern China, while the change in eastern China is weak. Five airports including Beijing, Shanghai, Kunming, Lasa and Urumqi will see ∼1.0°–2.0 °C (1.4°–3.0 °C) higher daily maximum temperature under 1.5 °C (2.0 °C) scenario. The half-degree additional warming will lead to a shift toward higher extreme temperature in these five sites. For both 1.5° and 2.0 °C scenarios, the number of Weight-restriction days will increase significantly at 3 airports including Beijing, Shanghai, and Lasa. Urumqi will witness an increase of Weight-restriction days only in 2.0 °C future.
Schwarz Carsten - One of the best experts on this subject based on the ideXlab platform.
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Wake Turbulence Evolution and Hazard Analysis for General Aviation Takeoff Accident
'American Institute of Aeronautics and Astronautics (AIAA)', 2019Co-Authors: Schwarz Carsten, Fischenberg Dietrich, Holzäpfel FrankAbstract:Wake turbulence is commonly a commercial aviation topic involving relatively heavy transport aircraft. However, wake turbulence is also safety relevant for business and general aviation flight operations. A detailed analysis has been conducted for a specific accident involving two aircraft of the wake turbulence category light. A four-seat aircraft with 1 ton maximum Takeoff Weight took off behind a biplane with 5.5 ton maximum Takeoff Weight. This led to a fatal accident. Based on available information and several assumptions, the wake turbulence aspects for the specific accident scenario have been assessed. The roll axis was the dominating factor in this case. Accordingly, the wake induced rolling moment was analyzed and related to the assumed available roll control power. Furthermore, the wake vortex behavior was simulated and analyzed in detail. The results indicate that wake turbulence can be considered to be the cause of the accident. The theoretical results and the conclusions regarding the accident are also supported by the results of flight tests, which were conducted in the context of the accident Investigation
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Wake Turbulence Evolution and Hazard Analysis for a General Aviation Takeoff Accident
'American Institute of Aeronautics and Astronautics (AIAA)', 2018Co-Authors: Schwarz Carsten, Fischenberg Dietrich, Holzäpfel FrankAbstract:Wake turbulence is commonly a commercial aviation topic involving relatively heavy transport aircraft. However, wake turbulence is also safety relevant for business and general aviation flight operations. A detailed analysis has been conducted for a specific accident involving two aircraft of the wake turbulence category light. A four-seat aircraft with one ton maximum Takeoff Weight took off behind a biplane with 5.5 tons maximum Takeoff Weight. This led to a fatal accident. Based on available information and several assumptions the wake turbulence aspects for the specific accident scenario have been assessed. The roll axis was the dominating factor in this case. Accordingly, the wake induced rolling moment was analyzed and related to the assumed available roll control power. Furthermore, the wake vortex behavior was simulated and analyzed in detail. The results indicate that wake turbulence can be considered to be the cause for the accident. The theoretical results and the conclusions regarding the accident are also supported by the results of flight tests, which were conducted in the context of the accident investigation
