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Journal articles on the topic 'Variable sweep wing'
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1
Xu, Lai Bin, Shu Xing Yang, and Bo Mo. "Controllability Analysis of Flexible Variable Sweep Control Wing." Advanced Materials Research 542-543 (June 2012): 873–77. http://dx.doi.org/10.4028/www.scientific.net/amr.542-543.873.
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Variable Sweep Control Wing (VSCW) was introduced to generate the rolling control moment with the sweep angle differences between the left and the right wings. Influence flexible matrixes were generated to obtain the deflection of the effective angle of attack (AOA) of the flexible swept wing. Comparison between aileron control surface and VSCW shows that VSCW can get benefit from wing flexibility, which degrades the control effectiveness of the traditional aileron. The main advantage and difference from the traditional aircraft is that VSCW has higher control effectiveness and can prevent control reversal especially at high flight speed range; and at low speed, with an AOA variation device VSCW can get similar rolling control performance compared with traditional aileron control surface.
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Tong, L., and H. Ji. "Multi-body dynamic modelling and flight control for an asymmetric variable sweep morphing UAV." Aeronautical Journal 118, no. 1204 (2014): 683–706. http://dx.doi.org/10.1017/s000192400000943x.
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AbstractIn this paper, the multi-body dynamic model of an asymmetric variable sweep wing morphing UAV is built based on Kane’s method. This model describes the UAV’s transient behaviour during morphing process and the dynamic characteristic of the variable sweep wings. An integrated design of trajectory tracking control via constrained backstepping method is presented then. The idea of aircraft roll control through asymmetric wing sweep angle changes rather than traditional aileron is explored and used in the fight control design. The control of variable sweep wings is designed as well based on the presented dynamic model. Command filters are used in the backstepping design procedure to accommodate magnitude, rate and bandwidth constraints on virtual states and actuator signals. Stability of the closed-loop system can be proved in the sense of Lyapunov. Simulation of tracking a desired trajectory which contains two manoeuvres demonstrates the feasibility of the proposed protocol and the morphing wing roll controller.
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Xu, Lai Bin, Shu Xing Yang, and Bo Mo. "Pitching Dynamic Response of Variable Sweep Wing Aircraft." Applied Mechanics and Materials 197 (September 2012): 159–63. http://dx.doi.org/10.4028/www.scientific.net/amm.197.159.
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The dynamic response of Variable Sweep Wing Aircraft (VSWA) with the wing sweeping is presented. The center of gravity (cg) of the aircraft, location of each wing partition , and moment of inertia alter significantly due to the wing morphing, resulting in considerably change of the dynamics of the aircraft. The extended equations of motion (EOMs) suitable for morphing wing aircraft are derived. Compared with the traditional EOMs, there are 4 additional forces and moments exhibiting in the extended EOMs due to the wing morphing. The results show that the additional forces and moments can affect the flight control considerably.
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An, Jiguang, Ming Yan, Wenbo Zhou, Xianghai Sun, Zhen Yan, and Chuanren Qiu. "Aircraft dynamic response to variable wing sweep geometry." Journal of Aircraft 25, no. 3 (1988): 216–21. http://dx.doi.org/10.2514/3.45580.
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Radhakrishnan P, Ramanan G, Chandan Gowda H R, Meghana C K, and Chaithra A N. "Aerodynamic Performance Analysis of a Variable Sweep Wing for Commercial Aircraft Applications." ACS Journal for Science and Engineering 1, no. 1 (2021): 31–37. http://dx.doi.org/10.34293/acsjse.v1i1.5.
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This study presents a detailed study on wing and its configurations and the morphing techniques for the wing. The morphing methods of the wing such as variable chord, variable span variable cambers have been studied in detail. In this study in detail about the effects of morphable sweep wing, the commercial aircraft wing has been designed and it‘s been modelled using the solid works software. To study the aerodynamic performance the wing, the wing has been analysed in ANSYS Fluent software and the results are interpreted in detail to analyze the effect of wing and its shapes. From the results it‘s been clear that at low speed (Mach=0.8) straight wing has high L/D ratio and at the sonic speed (Mach=1) sweep wing has higher L/D ratio and in Supersonic Speed (Mach=1.2) delta wing tends to have higher L/D ratio. Based on these results the wing can be morphed to the configurations to obtain a better performance in each flight regime. Based on these morphing, aircraft performance can be improved in all flight regimes.
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Greatwood, Colin, Antony Waldock, and Thomas Richardson. "Perched landing manoeuvres with a variable sweep wing UAV." Aerospace Science and Technology 71 (December 2017): 510–20. http://dx.doi.org/10.1016/j.ast.2017.09.034.
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Zong, Ning, Guang Jun Yang, and Sheng Li Lv. "Experimental Research on Aerodynamic Characteristics of Large Aspect Ratio Wing in Unfolding Process." Applied Mechanics and Materials 421 (September 2013): 56–61. http://dx.doi.org/10.4028/www.scientific.net/amm.421.56.
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For an unmanned aerial vehicle, in order to study the aerodynamic characteristics of the large aspect ratio wing during the deployment process with variable sweep angles, the scaled model was tested in the wind tunnel at different angles of attack with various sweep angles of wing. Experimental results indicate that the aerodynamic configuration satisfies the cruise design requirements, providing favorable longitudinal and lateral-directional stability. Fuselage of multi-plane combination brings beneficial effect for lift. Analysis have been made on the cases including wing flow separation which lead to the step of lift curve, and the existence of longitudinal unstable range during wing unfolding, which make the foundation for next optimum of configuration. The work described in this paper can be applied in the design of unmanned aerial vehicles, missiles and other research areas.
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Landfield, Joseph P., and Dario Rajkovic. "Canard/tail comparison for an advanced variable-sweep-wing fighter." Journal of Aircraft 23, no. 6 (1986): 449–54. http://dx.doi.org/10.2514/3.45328.
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Newman, Brett A., and Robert L. Swaim. "Classical flight dynamics of a variable forward-sweep-wing aircraft." Journal of Guidance, Control, and Dynamics 9, no. 3 (1986): 352–56. http://dx.doi.org/10.2514/3.20113.
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tarabi, abbas, sajjad ghasemloo, and mahmood mani. "Aerodynamic and Performance Evaluation of a Variable-Sweep Morphing Wing." Scientia Iranica 23, no. 6 (2016): 2694–703. http://dx.doi.org/10.24200/sci.2016.3978.
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Li, Yu, Lin Yi, Yuntu Ao, Liangzheng Ma, and Ying wang. "Simulation analysis the aerodynamic characteristics of variable sweep wing missile." Journal of Physics: Conference Series 1570 (June 2020): 012073. http://dx.doi.org/10.1088/1742-6596/1570/1/012073.
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Ma, Hang, Yuxue Ge, Bifeng Song, and Yang Pei. "Stability Analysis and Augmentation Design of a Bionic Multi-Section Variable-Sweep-Wing UAV Based on the Centroid Self-Trim Compensation Morphing." Applied Sciences 11, no. 19 (2021): 8859. http://dx.doi.org/10.3390/app11198859.
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In this study, a design scheme for a high-aspect-ratio bionic multi-section variable-sweep wing unmanned aerial vehicle (UAV) that utilizes the reverse coordinated change in the sweep angle of the inner and outer wing sections is proposed, which improves the aerodynamic performance and realizes the self-trim compensation of the wing’s centroid. According to the layout characteristics of this type of UAV, a reasonable distribution design of the wingspan ratio of the inner and outer sections is explored, to reduce the impact of aerodynamic center movement and moment of inertia change. The calculation and analysis results show that the coordinated variable-sweep scheme can significantly improve the influence of sweep angle change on the longitudinal static stability margin of UAVs with a high aspect ratio. The coordinated sweep angle change in the inner and outer wing sections can not only reduce the drag during high-speed flight, but also play a significant role in improving the performance of the aircraft at different stages in the mission profile. Appropriately increasing the wingspan proportion of the inner section can reduce the trim resistance of the V-tail, reduce the thrust of the engine, and increase the range and duration of the UAV. From the perspective of stability change, the multi-section variable-sweep wing UAV with a wingspan ratio of the inner and outer sections that is between 1.41 and 1.78 has better dynamic stability performance. Among them, the UAV with a wingspan ratio of the inner and outer sections that is equal to 1.41 has better longitudinal stability performance, while the UAV with a wingspan ratio of the inner and outer sections that is equal to 1.78 has better lateral/directional stability performance.
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Saravanan, P., S. Nadaraja Pillai, and K. M. Parammasivam. "Aerodynamic Characteristics of Hypersonic Vehicle with Variable Sweep back Wing Configuration." i-manager's Journal on Future Engineering and Technology 5, no. 1 (2009): 44–50. http://dx.doi.org/10.26634/jfet.5.1.1018.
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Chen, Shichun, Kuizhi Yue, Bing Hu, and Rui Guo. "Numerical Simulation on the Radar Cross Section of Variable-Sweep Wing Aircraft." Journal of Aerospace Technology and Management 7, no. 2 (2015): 170–78. http://dx.doi.org/10.5028/jatm.v7i2.416.
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Cangelosi, John. "VARIABLE SWEEP WING PLUS V/STOL - A NEW ERA IN AIRCRAFT DESIGN." Annals of the New York Academy of Sciences 107, no. 1 (2006): 280–99. http://dx.doi.org/10.1111/j.1749-6632.1963.tb13283.x.
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Kazan, E. "VARIABLE SWEEP WING PLUS V/STOL - A NEW ERA IN AIRCRAFT DESIGN." Annals of the New York Academy of Sciences 107, no. 1 (2006): 300–335. http://dx.doi.org/10.1111/j.1749-6632.1963.tb13284.x.
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Dai, Pei, Binbin Yan, Wei Huang, Yifei Zhen, Mingang Wang, and Shuangxi Liu. "Design and aerodynamic performance analysis of a variable-sweep-wing morphing waverider." Aerospace Science and Technology 98 (March 2020): 105703. http://dx.doi.org/10.1016/j.ast.2020.105703.
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Elelwi, M., M. A. Kuitche, R. M. Botez, and T. M. Dao. "Comparison and analyses of a variable span-morphing of the tapered wing with a varying sweep angle." Aeronautical Journal 124, no. 1278 (2020): 1146–69. http://dx.doi.org/10.1017/aer.2020.19.
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ABSTRACTThis work presents a comparative study of design and development, in addition, of analyses of variable span morphing of the tapered wing (VSMTW) for the unmanned aerial vehicle (UAV). The proposed concept consists in the sliding of the inner section into the fixed part along the wing with varying the angle of the inner section inside the fixed part (parallel with the leading edge and the moving-wing axis is coincident to the fixed-wing axis) within two configurations. The wing design is based on a NACA 4412 aerofoil with the root chord of 0.675m and the tip chord of 0.367m for the fixed segment and 0.320m for the moving segment. Morphing wing analysis occurs at three selected locations that have been specified for extending and modifying span length by (25%, 50%, and 75%) of its original length to fulfill various flight mission requirements. The main objective of this paper is to compare the aerodynamic characteristics for several span lengths and sweep angles and to find their most efficient combinations. The wing is optimised for different velocities during all phases of flight (min speed, loiter, cruise, and max speed) which are 17, 34, 51, and 68m/s, respectively. The analyses are performed by computing forces (drag and lift) and moments at various altitudes, such as at the sea level, at 5,000 and 10,000ft. Two-dimensional aerodynamic analyses are carried out using XFLR5 code, and the ANSYS Fluent solver is used for investigating the flow field on the three-dimensional wing structure. It has been observed that a variable span morphing of tapered wing technology with a variable sweep angle can deliver up to 32.93% improved aerodynamic efficiency. This concept design can also be used for the aircraft roll motion technique instead of conventional control devices. Furthermore, the range flight mission increases up to 46.89% when the wing is placed at its full length compared to an original position. Finally, it has been concluded from this study that the wing design is more sensitive to the changing angle of the inner section and more efficient in terms of aerodynamic characteristics.
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Moigne, A. Le, and N. Qin. "Aerofoil profile and sweep optimisation for a blended wing-body aircraft using a discrete adjoint method." Aeronautical Journal 110, no. 1111 (2006): 589–604. http://dx.doi.org/10.1017/s0001924000001457.
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Abstract Aerodynamic optimisations of a blended wing-body (BWB) aircraft are presented. A discrete adjoint solver is used to calculate efficiently the gradients, which makes it possible to optimise for a large number of design variables. The optimisations employ either a variable-fidelity method that combines low- and high-fidelity models or a direct sequential quadratic programming (SQP) method. Four Euler optimisations of a BWB aircraft are then presented. The optimisation is allowed to change a series of master sections defining the aircraft geometry as well as the sweep angle on the outer wing for two of the optimisations. Substantial improvements are obtained, not only in the Euler mode but also when the optimised geometries are evaluated using Reynolds-averaged Navier-Stokes solutions. Some interesting features of the optimised wing profiles are discussed.
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Dai, Pei, Binbin Yan, Ruifan Liu, Shuangxi Liu, and Mingang Wang. "Modeling and Nonlinear Model Predictive Control of a Variable-Sweep-Wing Morphing Waverider." IEEE Access 9 (2021): 63510–20. http://dx.doi.org/10.1109/access.2021.3074912.
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Guerrero, J. E., M. Sanguineti, and K. Wittkowski. "Variable cant angle winglets for improvement of aircraft flight performance." Meccanica 55, no. 10 (2020): 1917–47. http://dx.doi.org/10.1007/s11012-020-01230-1.
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Abstract Traditional winglets are designed as fixed devices attached at the tips of the wings. The primary purpose of the winglets is to reduce the lift-induced drag, therefore improving aircraft performance and fuel efficiency. However, because winglets are fixed surfaces, they cannot be used to control lift-induced drag reductions or to obtain the largest lift-induced drag reductions at different flight conditions (take-off, climb, cruise, loitering, descent, approach, landing, and so on). In this work, we propose the use of variable cant angle winglets which could potentially allow aircraft to get the best all-around performance (in terms of lift-induced drag reduction), at different flight phases. By using computational fluid dynamics, we study the influence of the winglet cant angle and sweep angle on the performance of a benchmark wing at Mach numbers of 0.3 and 0.8395. The results obtained demonstrate that by adjusting the cant angle, the aerodynamic performance can be improved at different flight conditions.
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Guerrero, Joel, Marco Sanguineti, and Kevin Wittkowski. "CFD Study of the Impact of Variable Cant Angle Winglets on Total Drag Reduction." Aerospace 5, no. 4 (2018): 126. http://dx.doi.org/10.3390/aerospace5040126.
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Winglets are commonly used drag-reduction and fuel-saving technologies in today’s aviation. The primary purpose of the winglets is to reduce the lift-induced drag, therefore improving fuel efficiency and aircraft performance. Traditional winglets are designed as fixed devices attached at the tips of the wings. However, because they are fixed surfaces, they give their best lift-induced drag reduction at a single design point. In this work, we propose the use of variable cant angle winglets which could potentially allow aircraft to get the best all-around performance (in terms of lift-induced drag reduction), at different angle-of-attack values. By using computational fluid dynamics, we study the influence of the winglet cant angle and sweep angle in the performance of a benchmark wing at a Mach number of 0.8395. The results obtained demonstrate that by carefully adjusting the cant angle, the aerodynamic performance can be improved at different angles of attack.
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Durmus, Seyhun. "Theoretical model proposal on direct calculation of wetted area and maximum lift-to-drag ratio." Aircraft Engineering and Aerospace Technology 93, no. 6 (2021): 1097–103. http://dx.doi.org/10.1108/aeat-02-2021-0038.
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Purpose As measuring flight performance by experimental methods requires a lot of effort and cost, theoretical models can bring new perspectives to aircraft design. This paper aims to propose a model on the direct calculation of wetted area and L/Dmax. Design/methodology/approach Model is based on idea that the wetted area is proportional to aircraft gross weight to the power of 2/3 (Wg2/3). Aerodynamic underpinning of this method is based on the square–cube law and the claim that parasitic drag is related to the Swet/Swing. The equation proposed by Raymer was used to find the L/Dmax estimate based on the calculated wetted area. The accuracy of the theoretical approach was measured by comparing the L/Dmax values found in the reference literature and the L/Dmax values predicted by the theoretical approach. Findings Proposed theoretical L/Dmax estimate matches with the actual L/Dmax data in different types of aircraft. Among the conventional tube-wing design, only the sailplanes have a very low Swet/Swing. The Swet/Swing of flying wings, blended wing bodies (BWBs) and large delta wings are lower than conventional tube-wing design. Lower relative wetted area (Swet/Swing) is the key design criterion in high L/Dmax targeted designs. Originality/value The proposed model could be used in wing sizing according to the targeted L/Dmax value in aircraft design. The approach can be used to estimate the effect of varying gross weight on L/Dmax. In addition, the model contributes to the L/Dmax estimation of unusual designs, such as variable-sweep wing, large delta wings, flying wings and BWBs. This study is valuable in that it reveals that L/Dmax value can be predicted only with aspect ratio, gross weight (Wg) and wing area (Swing) data.
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Reymer, Piotr, Marcin Kurdelski, Andrzej Leski, and Krzysztof Jankowski. "The Definition of the Load Spectrum for SU-22 Fighter-Bomber Full Scale Fatigue Test." Fatigue of Aircraft Structures 2015, no. 7 (2015): 28–33. http://dx.doi.org/10.1515/fas-2015-0005.
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Abstract The Su-22 fighter-bomber is a military aircraft used in the Polish Air Force since the mid 1980’s. By the decision of the Polish Ministry of Defense the predicted service life for this type of aircraft will be extended to 3200 flight hours. Due to the fact that some aircraft were nearing the end of the service life guaranteed by the manufacturer, the actual service life, determined based on the flight profile in the Polish Air Force, had to be validated. Consequently, the Full Scale Fatigue Test (FSFT) had to be carried out in order to verify that the required service life was attainable. This article describes the process of preparation of the load spectra used in the Su-22 FSFT. Due to the fact that the Su-22 has a variable sweep wing the whole test was divided into three Stages (landing, flight and flap loads) carried out at different wing sweep angles (30°/45°/30°). The spectra were developed using the historical data gathered from Flight Data Recorders (FDR), strain signals acquired during the Operational Load Monitoring program (OLM) and aerodynamic calculations.
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Lamar, J. "A career in vortices and edge forces." Aeronautical Journal 116, no. 1176 (2012): 101–52. http://dx.doi.org/10.1017/s0001924000006667.
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Abstract This lecture recognises the background and distinguished work of Frederick William Lanchester, and notes that my background has a few similarities with his. These include a shared interest in wings, lift and vortices. My career at the NASA Langley Research Center spans the time-frame from America’s Super Sonic Transport through 2009. An early emphasis involved wind-tunnel testing of research aircraft models and the development of computer codes for subsonic aerodynamics of wing planforms. These attached-flow codes were applied to various configurations, including those with variable-sweep, dihedral, and more than one planform in both the analysis- and design-modes. These codes were used to provide a connection between leading-edge-forces and the associated additional lift on delta-wings with shed-vortex systems through the leading-edge suction analogy of Edward C. Polhamus. Subsequently, I extended the suction analogy to configurations with side-edges to predict the vortical-flow aerodynamics on complex configurations, including wing-strake combinations. These analysis codes could also be used in a design-by-analysis mode for configurations with leading-edge shed vortices. Later, I was involved in vortical-flow flight research with the F-106B and the F-16XL aircraft at cruise and maneuver conditions. Associated CFD predictions, generated by me and other members of the RTO/AVT-113 task group, have increased our understanding of the flight flow-physics measured on the F-16XL aircraft.
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Gao, Liang, Hongzhe Jin, Jie Zhao, Hegao Cai, and Yanhe Zhu. "Flight Dynamics Modeling and Control of a Novel Catapult Launched Tandem-Wing Micro Aerial Vehicle With Variable Sweep." IEEE Access 6 (2018): 42294–308. http://dx.doi.org/10.1109/access.2018.2858293.
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Wen, Nuan, Zhenghua Liu, and Lingpu Zhu. "Linear-parameter-varying-based adaptive sliding mode control with bounded L2 gain performance for a morphing aircraft." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 233, no. 5 (2018): 1847–64. http://dx.doi.org/10.1177/0954410018764472.
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Large-scale morphing aircraft can adaptively alter configuration according to the different flight conditions or a variety of missions to ensure the optimal aerodynamic performance. However, this will certainly put forward a higher request to modeling method and controller performance. In this paper, we propose an adaptive sliding mode control strategy with bounded L2 gain performance based on linear-parameter-varying methodology for the robust control of a morphing aircraft with variable span and variable sweep angle. Using the Kane method, the longitudinal dynamic model of the morphing aircraft is derived. Moreover, the linearized linear-parameter-varying model of the aircraft in the wing varying process is formulated for controller synthesis. The adaptive sliding mode control synthesis for this uncertain linear-parameter-varying system consists of two steps. Firstly, based on the full block S-procedure, the sufficient condition in form of linear matrix inequality constrains is derived for the existence of a reduced-order sliding mode dynamics. Then, the synthesized adaptive sliding mode control is proved to drive the linear-parameter-varying system trajectories onto the predefined switching surface without the information of upper bound of external disturbances. The performance and robustness of the proposed controller are verified by the numerical results.
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Hang, Chengguang, Xijie Gao, Botao Wang, Mengchan Yuan, Yuxiang Huang, and Ruixiang Zhu. "Optimization of the Wing Parameters for a Winged Subsoiler." Applied Engineering in Agriculture 33, no. 3 (2017): 313–19. http://dx.doi.org/10.13031/aea.12068.
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ABSTRACT. The wing parameters of a subsoiler, such as the location and angle of the wings, have an important impact on the operating performance of the winged subsoilers. To study the comprehensive effect of wing parameters and to determine the optimal parameters of a winged subsoiler, a field experiment was conducted. The experimental factors were the mounting height (50, 100, 150, 200, and 250 mm), sweep angle(5°, 15°, 25°, 35°, and 45°) and mounting angle(5°, 15°, 25°, 35°, and 45°). The draft force of the subsoiler and the disturbed soil area were measured; these two variables defined the Specific Draft Force (SDF). The SDF was used as the response index to evaluate the performance of the winged subsoiler. The mathematical model of regression between experimental factors and SDF was established. The results showed that the normal probability distribution of the predicted and measured values of SDF tended to be linear, indicating that the credibility of the results of the analysis was higher. The mounting height, mounting angle, and sweep angle had interactive effects on SDF. The order of significance was mounting height, mounting angle, and sweep angle. The experimental parameters were optimized by Design-Expert 8.0 software: 124 mm for the mounting height, 45° for the mounting angle, and 45° for the sweep angle. This optimal combination of parameters resulted in a SDF of 69.9 kN/m2. The winged subsoiler designed using the optimization results showed that the average value of SDF was 78.73 kN/m2: significantly lower than SDF (79.34-95.33 kN/m2) before optimization. Keywords: Mounting angle, Mounting height, Optimization, Parameter, Specific Draft Force (SDF), Subsoiler, Sweep angle, Wing.
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Ashikhmina, E. R., and P. V. Prosuntsov. "Wing Shape Optimization and Selecting Rational Re-Entry Trajectory for Reusable Spacecraft of Tourist Class." Proceedings of Higher Educational Institutions. Маchine Building, no. 8 (737) (August 2021): 74–86. http://dx.doi.org/10.18698/0536-1044-2021-8-74-86.
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The article considers solving the interrelated problems of wing shape optimization and synthesis of the re-entry trajectory control law for the reusable spacecraft of tourist class. To ensure a high aerodynamic quality of the wing, increase its bearing properties, as well as improve the maneuverability and controllability of the spacecraft as a whole, the wing shape has been optimized for sub- and supersonic flight modes. The problem of minimizing the wing area is solved for subsonic flight speed while ensuring the level of lift sufficient for landing, with the introduction of restrictions on the minimum wing sweep angle. For supersonic flight speed, maximization of the aerodynamic quality of the wing is used as an objective function. The length and taper of the wing, leading-edge sweep angle, the size of the root and tip chords, and the position of the wing relative to the fuselage were chosen as variables. For the wing shape selected on the basis of the parametric analysis, the calculation of the dependences of the spacecraft aerodynamic coefficients on the Mach number, used for selecting a rational program for the descent control in the atmosphere, was carried out. The choice of a rational control program is made with restrictions on the level of overloads, kinetic pressure and maximum heat flux.
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Wang, Chen, De Zhou Meng, and Xu Fang Bo. "The Research about the Wind Turbines Pitch Control." Advanced Materials Research 773 (September 2013): 87–90. http://dx.doi.org/10.4028/www.scientific.net/amr.773.87.
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Based on the background of wind power, considering the wind blade sweep area on the uneven distribution, this paper is using the PID control algorithm to control the pitch system. At the same time, this paper is using Siemens SCL to programming, simulating on the experimental platform. Simulation results show the validity of the theory and the feasibility of the system, realizing variable pitch control of fan blade.
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Drofelnik, Jernej, Andrea Da Ronch, Matteo Franciolini, and Andrea Crivellini. "Fast identification of transonic buffet envelope using computational fluid dynamics." Aircraft Engineering and Aerospace Technology 91, no. 2 (2019): 309–16. http://dx.doi.org/10.1108/aeat-01-2018-0057.
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Purpose This paper aims to present a numerical method based on computational fluid dynamics that allows investigating the buffet envelope of reference equivalent wings at the equivalent cost of several two-dimensional, unsteady, turbulent flow analyses. The method bridges the gap between semi-empirical relations, generally dominant in the early phases of aircraft design, and three-dimensional turbulent flow analyses, characterised by high costs in analysis setups and prohibitive computing times. Design/methodology/approach Accuracy in the predictions and efficiency in the solution are two key aspects. Accuracy is maintained by solving a specialised form of the Reynolds-averaged Navier–Stokes equations valid for infinite-swept wing flows. Efficiency of the solution is reached by a novel implementation of the flow solver, as well as by combining solutions of different fidelity spatially. Findings Discovering the buffet envelope of a set of reference equivalent wings is accompanied with an estimate of the uncertainties in the numerical predictions. Just over 2,000 processor hours are needed if it is admissible to deal with an uncertainty of ±1.0° in the angle of attack at which buffet onset/offset occurs. Halving the uncertainty requires significantly more computing resources, close to a factor 200 compared with the larger uncertainty case. Practical implications To permit the use of the proposed method as a practical design tool in the conceptual/preliminary aircraft design phases, the method offers the designer with the ability to gauge the sensitivity of buffet on primary design variables, such as wing sweep angle and chord to thickness ratio. Originality/value The infinite-swept wing, unsteady Reynolds-averaged Navier–Stokes equations have been successfully applied, for the first time, to identify buffeting conditions. This demonstrates the adequateness of the proposed method in the conceptual/preliminary aircraft design phases.
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Widodo, Aris Slamet. "The Influence of Risk Production Level toward Optimization Conservation Farming at Coastal Land in Yogyakarta Special Province, Indonesia." KnE Life Sciences 3, no. 3 (2016): 67. http://dx.doi.org/10.18502/kls.v3i3.402.
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<p>This research study aimed to analyse the influence of joint-well irrigation technology and windbarrier vegetation to the risk-production as well as to analyse the optimum resource allocation of conservation farming at coastal land influenced by risk-production. The research method applied in this study was a survey method. The location of study was along Samas coastal line in Yogyakarta Special Province, Indonesia. The risk-analysis technique used was maximum likelihood estimation method. The analysis of optimizing done by linier programming method by concluding variable of risk-production (windbarrier and joint-well irrigation technology). The research findings concluded that conservation farming at coastal land was that farming done at coastal land aiming to get farming profit and conserve coastal land by cultivating windbarrier plants and providing joint-well irrigation system as well. The analysis of risk-production concluded that variable of windbarrier on rainy season could significantly decrease risk-production against cultivating shallots worth 29.92%, eggplants worth 14.99%, and sweet potatoes worth 6.96% for every adding 1% of windbarier unit, while variable of joint-well only influenced toward risk-production on farming eggplants worth 2.61%. On rainy season 1, variable of jointwell influenced risk-production toward farming shallots worth 18,67% and sweet potatoes worth 20.07%, while variable of wind-barrier influenced significantly toward the farming shallots worth 21.63%, red chillies with 14.05% and sweet potatoes with 4.16%. On dry season 2, variable of joint-well only influenced risk-production on farming sweet potatoes with 13.69%, while variable of wind-barrier only infuenced farming shallots worth 28.21%. Allocation of conservation farming resources at coastal lands by concluding variable of riskproduction (wind-barier and joint-well irrigation technology) has been optimal. Maximum income earned by farmers was Rp 11,647,110.-/year. </p><p><strong>Key words</strong>: optimising, risk-production, conservation farming, coastal land. 1</p>
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Knörnschild, Mirjam, Marion Feifel, and Elisabeth K. V. Kalko. "Male courtship displays and vocal communication in the polygynous bat Carollia perspicillata." Behaviour 151, no. 6 (2014): 781–98. http://dx.doi.org/10.1163/1568539x-00003171.
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Male courtship behaviour towards choosy females often comprises elaborate displays that address multiple sensory channels. In bats, detailed quantitative descriptions of multimodal courtship displays are still fairly scarce, despite the taxon’s speciose nature. We studied male courtship behaviour in a polygynous Neotropical bat, Seba’s short-tailed fruit bat Carollia perspicillata, by monitoring harem males in a captive colony. Courting male C. perspicillata performed stereotypic tactile, visual and acoustic displays. A courtship sequence, directed at one female at a time, lasted up to 120 s. During courtship, males approached females by brachiating or flying, hovered in front of them, pursued them on the wing, sniffed them and repeatedly poked the females with one or both folded wings; the latter behaviour was the most conspicuous male courtship display. Immediately before copulation, males wrapped their wings around the females and bit their necks. As acoustic display, courting male C. perspicillata produced highly variable, monosyllabic courtship trills. The species’ vocal repertoire consisted of ten different social vocalisation types, three for benign interactions (courtship trills, wobbles, isolation calls), four for aggressive encounters (aggressive trills, down-sweeps, warbles, distress calls) and the remaining three for unknown behavioural contexts (V-shaped calls, flat down-sweeps, hooks). Courtship trills and aggressive trills were exclusively produced by males. We measured 245 courtship trills of five males and found statistical evidence for a strong individual signature which has the potential to facilitate female choice, mate recognition or neighbour–stranger recognition among male competitors.
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Pandorfi, Héliton, Alan C. Bezerra, Roberto T. Atarassi, Frederico M. C. Vieira, José A. D. Barbosa Filho, and Cristiane Guiselini. "Artificial neural networks employment in the prediction of evapotranspiration of greenhouse-grown sweet pepper." Revista Brasileira de Engenharia Agrícola e Ambiental 20, no. 6 (2016): 507–12. http://dx.doi.org/10.1590/1807-1929/agriambi.v20n6p507-512.
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ABSTRACT This study aimed to investigate the applicability of artificial neural networks (ANNs) in the prediction of evapotranspiration of sweet pepper cultivated in a greenhouse. The used data encompass the second crop cycle, from September 2013 to February 2014, constituting 135 days of daily meteorological data, referring to the following variables: temperature and relative air humidity, wind speed and solar radiation (input variables), as well as evapotranspiration (output variable), determined using data obtained by load-cell weighing lysimeter. The recorded data were divided into three sets for training, testing and validation. The ANN learning model recognized the evapotranspiration patterns with acceptable accuracy, with mean square error of 0.005, in comparison to the data recorded in the lysimeter, with coefficient of determination of 0.87, demonstrating the best approximation for the 4-21-1 network architecture, with multilayers, error back-propagation learning algorithm and learning rate of 0.01.
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Thelen, Andrew, Leifur Leifsson, Anupam Sharma, and Slawomir Koziel. "RANS-based design optimization of dual-rotor wind turbines." Engineering Computations 35, no. 1 (2018): 35–52. http://dx.doi.org/10.1108/ec-10-2016-0354.
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Purpose An improvement in the energy efficiency of wind turbines can be achieved using dual rotors. Because of complex flow physics, the design of dual-rotor wind turbines (DRWTs) requires repetitive evaluations of computationally expensive partial differential equation (PDE) simulation models. Approaches for solving design optimization of DRWTs constrained by PDE simulations are investigated. The purpose of this study is to determine design optimization algorithms which can find optimal designs at a low computational cost. Design/methodology/approach Several optimization approaches and algorithms are compared and contrasted for the design of DRWTs. More specifically, parametric sweeps, direct optimization using pattern search, surrogate-based optimization (SBO) using approximation-based models and SBO using kriging interpolation models with infill criteria are investigated for the DRWT design problem. Findings The approaches are applied to two example design cases where the DRWT fluid flow is simulated using the Reynolds-averaged Navier−Stokes (RANS) equations with a two-equation turbulence model on an axisymmetric computational grid. The main rotor geometry is kept fixed and the secondary rotor characteristics, using up to three variables, are optimized. The results show that the automated numerical optimization techniques were able to accurately find the optimal designs at a low cost. In particular, SBO algorithm with infill criteria configured for design space exploitation required the least computational cost. The widely adopted parametric sweep approach required more model evaluations than the optimization algorithms, as well as not being able to accurately find the optimal designs. Originality/value For low-dimensional PDE-constrained design of DRWTs, automated optimization algorithms are essential to find accurately and efficiently the optimal designs. More specifically, surrogate-based approaches seem to offer a computationally efficient way of solving such problems.
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Asplen, Mark K. "Proximate Drivers of Migration and Dispersal in Wing-Monomorphic Insects." Insects 11, no. 1 (2020): 61. http://dx.doi.org/10.3390/insects11010061.
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Gains in our knowledge of dispersal and migration in insects have been largely limited to either wing-dimorphic species or current genetic model systems. Species belonging to these categories, however, represent only a tiny fraction of insect biodiversity, potentially making generalization problematic. In this perspective, I present three topics in which current and future research may lead to greater knowledge of these processes in wing-monomorphic insects with limited existing molecular tools. First, threshold genetic models are reviewed as testable hypotheses for the heritability of migratory traits, using the sweet potato whitefly (Bemisia tabaci) as a case study of a behaviorally-polymorphic migratory species lacking morphological or physiological differentiation. In addition, both adaptive and non-adaptive explanations for the empirically variable relationship between egg production and flight in wing-monomorphic insects are discussed. Finally, with respect to the largest order of insects (Hymenoptera), the role of sex determination mechanisms for haplodiploidy as a driver for natal dispersal (for inbreeding avoidance) versus philopatry (such as in local mate competition) is discussed.
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Allen, N., S. Lawson, M. Maina, and J. Alderman. "Qualification of the ARA TWT for laminar flow testing." Aeronautical Journal 118, no. 1209 (2014): 1349–58. http://dx.doi.org/10.1017/s0001924000010009.
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Abstract The current drive towards reducing the environmental impact of aircraft necessitates the ability to evaluate techniques for promoting natural laminar flow in a large scale wind tunnel facility. A test was undertaken on the M2355 variable sweep model to obtain temperature sensitive paint (TSP) and hot-film data from which the transition locations at a range of sweep angles and flow conditions could be identified. The TSP technique has been shown to be a reliable method for determining transition on suitably treated wind tunnel models. Pressure data were also acquired and interpolated to provide the input to the laminar boundary layer code, BL2D, the output from which was used in the linear stability analysis code, CoDS, to calculate the N-factor for the ARA TWT (Transonic Wind Tunnel) facility. Two sets of N-factors were calculated, firstly using incompressible analysis with stationary crossflow and secondly using compressible analysis with travelling crossflow. In both analyses the Tollmien-Schlichting and crossflow cases were calculated together, rather than separating the cases before running the analysis. The resulting N-factors indicate a degree of scatter typical for experimental data. The N-factor based on incompressible theory for crossflow was found to be approximately 7 and for Tollmien-Schlichting (T-S), approximately 11. The results of the wind tunnel test and the analysis carried out are considered to be the first steps towards establishing a methodology for performance testing, in atmospheric tunnels such as the TWT, for aircraft designed to have significant regions of laminar flow. The project has also provided a body of experimental test data which will be valuable for future research into development and validation of laminar flow methods.
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Chu, You-Hua. "Ring nebulae around massive stars throughout the Hertzsprung-Russell diagram." Symposium - International Astronomical Union 212 (2003): 585–95. http://dx.doi.org/10.1017/s0074180900212965.
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Massive stars evolve across the H-R diagram, losing mass along the way and forming a variety of ring nebulae. During the main sequence stage, the fast stellar wind sweeps up the ambient interstellar medium to form an interstellar bubble. After a massive star evolves into a red giant or a luminous blue variable, it loses mass copiously to form a circumstellar nebula. As it evolves further into a WR star, the fast WR wind sweeps up the previous mass loss and forms a circumstellar bubble. Observations of ring nebulae around massive stars not only are fascinating, but also are useful in providing templates to diagnose the progenitors of supernovae from their circumstellar nebulae. In this review, I will summarize the characteristics of ring nebulae around massive stars throughout the H-R diagram, show recent advances in X-ray observations of bubble interiors, and compare supernovae's circumstellar nebulae with known types of ring nebulae around massive stars.
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Stanley, Andrew P. J., Owen Roberts, Jennifer King, and Christopher J. Bay. "Objective and algorithm considerations when optimizing the number and placement of turbines in a wind power plant." Wind Energy Science 6, no. 5 (2021): 1143–67. http://dx.doi.org/10.5194/wes-6-1143-2021.
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Abstract. Optimizing turbine layout is a challenging problem that has been extensively researched in the literature. However, optimizing the number of turbines within a given boundary has not been studied as extensively and is a difficult problem because it introduces discrete design variables and a discontinuous design space. An essential step in performing wind power plant layout optimization is to define the objective function, or value, that is used to express what is valuable to a wind power plant developer, such as annual energy production, cost of energy, or profit. In this paper, we demonstrate the importance of selecting the appropriate objective function when optimizing a wind power plant in a land-constrained site. We optimized several different wind power plants with different wind resources and boundary sizes. Results show that the optimal number of turbines varies drastically depending on the objective function. For a simple, one-dimensional, land-based scenario, we found that a wind power plant optimized for minimal cost of energy produced just 72 % of the profit compared to the wind power plant optimized for maximum profit, which corresponded to a loss of about USD 2 million each year. This paper also compares the performance of several different optimization algorithms, including a novel repeated-sweep algorithm that we developed. We found that the performance of each algorithm depended on the number of design variables in the problem as well as the objective function.
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Ruiz-Bejarano, M. Jesús, Enrique Durán-Guerrero, Remedios Castro, Carmelo G. Barroso, and M. Carmen Rodríguez-Dodero. "Use of Sensory Analysis to Investigate the Influence of Climate Chambers and Other Process Variables in the Production of Sweet Wines." Foods 9, no. 4 (2020): 424. http://dx.doi.org/10.3390/foods9040424.
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In this study, a climate chamber, as an alternative method, has been used to dry raisins and the sensory profiles of the sweet sherry wines obtained have been evaluated. Other important factors, namely grape variety, vintage, vinification conditions, as well as the ageing method and its length of time, have also been considered. When heavy rainfall had been registered, the musts extracted from grapes dried under controlled conditions in a climate chamber showed a lower intensity of the musty off-odor compared to those elaborated with sun-dried grapes. The wine fermented at low temperature with Saccharomyces bayanus scored the highest in citric and floral notes, and this was preferred over all the other wines that were evaluated. The wines aged in oak barrels were preferred to both, wines aged in the presence of oak chips as well as those aged without any wood contact. The use of climate chambers to dry the grapes that are going to be used for the elaboration of sweet wines appears to be an advantageous alternative to the traditional method, since it allows a more precise control of the process and highly valued sweet wines from a sensory point of view are obtained thereby.
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Gong, Ligang, Qing Wang, Chaoyang Dong, and Kewei Zhong. "Prescribed performance control of morphing aircraft based on switched nonlinear systems and reinforcement learning." Measurement and Control 52, no. 5-6 (2019): 608–24. http://dx.doi.org/10.1177/0020294019830434.
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The prescribed performance control of a morphing aircraft with variable sweep wings is investigated based on switched nonlinear systems and reinforcement learning. Switched nonlinear systems in lower triangular form are first adopted to describe the longitudinal altitude motion, and an error transformation is applied to handle the prescribed performance bound. Then, the designed controller is divided into the basic part and supplementary part. For the basic part, the backstepping method with involvement of the modified dynamic surface control technique is utilized to avoid the “explosion of complexity” problem. Improved disturbance observers inspired from the idea of extended state observer are then designed to estimate the disturbances and combined with radial basis function neural networks to develop the common virtual control laws. Moreover, by using the error variables defined in the backstepping design, the reinforcement learning–based supplementary part controller is devised with the critic-action neural network structure, which can adjust its parameters online and further decrease the altitude tracking error. It is proved that all signals of the closed-loop system are uniformly ultimately bounded, and the prescribed performance bound for convergence of the altitude tracking error can be satisfied. Finally, comparative simulations demonstrate the effectiveness of the proposed control approach.
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Petronilho, Sílvia, Ricardo Lopez, Vicente Ferreira, Manuel A. Coimbra, and Sílvia M. Rocha. "Revealing the Usefulness of Aroma Networks to Explain Wine Aroma Properties: A Case Study of Portuguese Wines." Molecules 25, no. 2 (2020): 272. http://dx.doi.org/10.3390/molecules25020272.
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Wine aroma is the result of complex interactions between volatile compounds and non-volatile ones and individual perception phenomenon. In this work, an aroma network approach, that links volatile composition (chromatographic data) with its corresponding aroma descriptors was used to explain the wine aroma properties. This concept was applied to six monovarietal wines from Bairrada Appellation (Portugal) and used as a case study. A comprehensive determination of the wines’ volatile composition was done (71 variables, i.e., volatile components), establishing a workflow that combines extraction techniques and gas chromatographic analysis. Then, a bipartite network-based approach consisting of two different nodes was built, one with 19 aroma descriptors, and the other with the corresponding volatile compound(s). To construct the aroma networks, the odor active values were calculated for each determined compound and combined with the bipartite network. Finally, the aroma network of each wine was compared with sensory descriptive analysis. The analysis of the specific aroma network of each wine revealed that Sauvignon Blanc and Arinto white wines present higher fruity (esters) and sweet notes (esters and C13 norisoprenoids) than Bical wine. Sauvignon Blanc also exhibits higher toasted aromas (thiols) while Arinto and Bical wines exhibit higher flowery (C13 norisoprenoids) and herbaceous notes (thiols), respectively. For red wines, sweet fruit aromas are the most abundant, especially for Touriga Nacional. Castelão and Touriga Nacional wines also present toasted aromas (thiols). Baga and Castelão wines also exhibit fusel/alcohol notes (alcohols). The proposed approach establishes a chemical aroma fingerprint (aroma ID) for each type of wine, which may be further used to estimate wine aroma characteristics by projection of the volatile composition on the aroma network.
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Hennig, Ernest, and Dominique Mazzi. "Spotted Wing Drosophila in Sweet Cherry Orchards in Relation to Forest Characteristics, Bycatch, and Resource Availability." Insects 9, no. 3 (2018): 118. http://dx.doi.org/10.3390/insects9030118.
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Forest vegetation is essential for the population development of the spotted wing drosophila (SWD). Yet, little is known of how the structure of surrounding forest areas influence the abundance of SWD within orchards. In this work, we use data from a field trial at five sites in Switzerland to analyse the relationship between the extent of forest area, its edge density, and its distance from the orchard with the occurrence of SWD in sweet cherry orchards in a Bayesian hierarchical model. Availability of cherries and bycatch were also included in the model to account for effects of resource availability and trap attractiveness, respectively. For all main effects and their interactions, we accounted for potential temporal changes by adding interactions with time. We found that the closer an orchard was to a forest, the more SWD were trapped within the orchard. However, the interaction of forest proximity with forest area caused a disproportionate decrease of SWD catches. Also, the within orchard variables, trap catches of other drosophilid flies and resource availability affected SWD trap catches, but their relation changed in the course of the experiment. The findings imply that reducing SWD occurrence in orchards and other crop fields requires not only the consideration of processes outside and within the host crop field, but also of temporally changing relationships between SWD and other factors.
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Cattell, C., B. Short, A. Breneman, et al. "Narrowband oblique whistler-mode waves: comparing properties observed by Parker Solar Probe at <0.3 AU and STEREO at 1 AU." Astronomy & Astrophysics 650 (June 2021): A8. http://dx.doi.org/10.1051/0004-6361/202039550.
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Aims. Large amplitude narrowband obliquely propagating whistler-mode waves at frequencies of ~0.2 fce (electron cyclotron frequency) are commonly observed at 1 AU, and they are most consistent with the whistler heat flux fan instability. We want to determine whether similar whistler-mode waves occur inside 0.3 AU and how their properties compare to those at 1 AU. Methods. We utilized the waveform capture data from the Parker Solar Probe Fields instrument from Encounters 1 through 4 to develop a data base of narrowband whistler waves. The Solar Wind Electrons Alphas and Protons Investigation (SWEAP) instrument, in conjunction with the quasi-thermal noise measurement from Fields, provides the electron heat flux, beta, and other electron parameters. Results. Parker Solar Probe observations inside ~0.3 AU show that the waves are often more intermittent than at 1 AU, and they are interspersed with electrostatic whistler-Bernstein waves at higher-frequencies. This is likely due to the more variable solar wind observed closer to the Sun. The whistlers usually occur within regions when the magnetic field is more variable and often with small increases in the solar wind speed. The near-Sun whistler-mode waves are also narrowband and large amplitude, and they are associated with beta greater than 1. The association with heat flux and beta is generally consistent with the whistler fan instability. Strong scattering of strahl energy electrons is seen in association with the waves, providing evidence that the waves regulate the electron heat flux.
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Pittari, Elisabetta, Luigi Moio, Panagiotis Arapitsas, et al. "Exploring Olfactory–Oral Cross-Modal Interactions through Sensory and Chemical Characteristics of Italian Red Wines." Foods 9, no. 11 (2020): 1530. http://dx.doi.org/10.3390/foods9111530.
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This work aimed at investigating red wine olfactory–oral cross-modal interactions, and at testing their impact on the correlations between sensory and chemical variables. Seventy-four Italian red whole wines (WWs) from 10 varieties, and corresponding deodorized wines (DWs), were evaluated by sensory descriptive assessment. Total phenols, proanthocyanidins, ethanol, reducing sugars, pH, titratable and volatile acidity were determined. PCA results highlighted different sensory features of the 10 wine types. ANOVAs (p < 0.05) showed that olfactory cues might play modulation effects on the perception of in-mouth sensations with 7 (harsh, unripe, dynamic, complex, surface smoothness, sweet, and bitter) out of 10 oral descriptors significantly affected by odours. Three weak but significant positive correlations (Pearson, p < 0.0001) were statistically found and supported in a cognitive dimension: spicy and complex; dehydrated fruits and drying; vegetal and unripe. In the absence of volatiles, correlation coefficients between sensory and chemical parameters mostly increased. Proanthocyanidins correlated well with drying and dynamic astringency, showing highest coefficients (r > 0.7) in absence of olfactory–oral interactions. Unripe astringency did not correlate with polyphenols supporting the idea that this sub-quality is a multisensory feeling greatly impacted by odorants. Results support the significance of cross-modal interactions during red wine tasting, confirming previous findings and adding new insights on astringency sub-qualities and their predictive parameters.
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Žiarovská, Jana, Veronika Fialková, Lucia Zamiešková, Jana Bilčíková, Lucia Zeleňáková, and Miroslava Kačániová. "Expression pattern of thaumatin in the selected red varieties of Vitis vinifera, L." Potravinarstvo Slovak Journal of Food Sciences 13, no. 1 (2019): 547–52. http://dx.doi.org/10.5219/1057.
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Vitis vinifera L. is a specie that is adapted to a very variable range of climates, from cold up to the desert one, but especially it grows in the temperate Mediterranean regions and continental areas of Europe. Grape is a widespread consumed fruit as well as processed to musts, juices or wine. The health beneficial effects of grapes and wine are very well known due to their high nutritional value and unique phytochemical composition. Despite many health protective and beneficial effects of Vitis vinifera, a part of population suffer to allergic reactions to this fruit. Allergens of wine and grapes are: endochitinases, lipid-transfer protein and thaumatin. Thaumatin is a protein having a sweet taste belonging to the PR5-like proteins. These proteins are very difersified in their functions and were described to be involved in stress responses and fruit ripening, but are expressed in healthy grape fruits in a constitutive manner and needn´t to be expressed only as a answer to the stress. Thaumatin is a minor allergen in grape, but belonging to the suspected panallergens relevant to the food cross-allergy induction, its importance is quite high. Another importance of this protein is a technological one, as reported to aggregate in wine to form a visible haze unless removed prior to bottling. In this study, expression of thaumatin-like allergen was analysed in the grapes of selected varieties. Grapes of four red varieties of Vitis vinifera, L. were obtained in the season 2017 in the Sabo winery that belongs to the Malokarpatská wine region. Fresh maturated grapes of varieties Alibernet, Cabernet Sauvignon , Frankovka modrá and Dornfelder were analysed. Expression changes of thaumatin was calculated by delta delta Ct method. Dornfelder was found as to have the lowest activity in thaumatin-like gene activity, mainly when comparing to the Cabernet Sauvignon and Frankovka modrá. Alibernet, on the other side, has the expression level of thaumatin very similar when comparing to the Cabernet Sauvignon and Frankovka modrá.
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Zhou, Chenni, Mo Li, Lu Liu, Fangjie Zhao, Wenfeng Cong, and Fusuo Zhang. "Food Consumption and Dietary Patterns of Local Adults Living on the Tibetan Plateau: Results from 14 Countries along the Yarlung Tsangpo River." Nutrients 13, no. 7 (2021): 2444. http://dx.doi.org/10.3390/nu13072444.
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The distinct Tibetan regional diet is strongly influenced by the regional biogeography, indigenous traditions, popular religious beliefs and food taboos. In the context of the nutritional transition in Tibet, studies seldom report on the food consumption and dietary patterns of Tibetan residents. This is a cross-section study of 552 local adults (≥18 years old, 277 men and 275 women) living in 14 agricultural countries along the Yarlung Tsangpo River. Dietary intakes were assessed by a culturally specific FFQ and compared with the Chinese Dietary Pagoda (2016). Dietary Patterns were extracted by using PCA method. The binary logistic regression model was applied to assess the association between independent variables (genders, regions and age groups) and adherence to dietary patterns. With the exception of meat (100 ± 260 g/day) and soybean nuts (42 ± 12 g/day), which exceeded the recommended dietary intakes of CDP, the dietary intake of other foods were not up to the recommended value. In particular, the intake of aquatic products (2 ± 0.1 g/day), vegetables (90 ± 19 g/day), dairy products (114 ± 29 g/day), cereals (117 ± 27 g/day) and fruits (97 ± 25 g/day) were seriously inadequate, which were 95%, 70%, 62%, 53.2% and 51.5% lower than the recommended intakes, respectively. Four dietary patterns were identified. “Local traditional diet” was characterized by a high intake of tsampa (roasted highland barley flour), culturally specific beverages (sweet tea and yak buttered tea), potato and yak beef and was associated with female, rural and older adults (≥51 years old). The male, urban and 18~30 years old group had a higher adherence score with the “Han diet”, which was comprised of rice, pork, dumplings, eggs, milk and cabbage. The “Beverage diet”, which mainly include tsampa, chang (homemade barley wine) and sweet tea, was associated with the following group: female, urban and aged 18~30 years. The “Out-sourced diet” pattern, consisting of mainly rice, steam bread and some processed meat, was associated with being male, urban and 18–30 years of age. These findings indicate that the dietary practice of the Tibetan people still has strong local characteristics, but it is also undergoing a dietary transition with the penetration of the Chinese Han diet and the increased consumption of outsourced (processed) foods. The unbalanced dietary intake of Tibetan residents should be taken seriously by all parties.
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Cravero, Maria Carla, Monica Laureati, Sara Spinelli, et al. "Profiling Individual Differences in Alcoholic Beverage Preference and Consumption: New Insights from a Large-Scale Study." Foods 9, no. 8 (2020): 1131. http://dx.doi.org/10.3390/foods9081131.
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Alcoholic beverage consumption plays an important role in European culture, and in many contexts drinking alcohol is socially acceptable and considered part of the diet. Understanding the determinants of alcohol preference and consumption is important not only for disease prevention, intervention, and policy management, but also for market segmentation, product development, and optimization. The aim of the study was to investigate the effect of individual responsiveness to various oral sensations on self-reported liking and intake of 14 alcoholic and non-alcoholic beverages (including beers, wines, spirits, and cocktails) considering gender, age, and oral responsiveness (measured through response to 6-n-propyl-2-thiouracil -PROP, basic tastes, astringency, and pungency) in a large sample of Italian consumers. Data were collected from 2388 respondents (age range 18–60 years; mean age = 37.6, SD = 13.1; 58.2% women). These results indicate that notwithstanding the strong gender difference, with women generally liking and consuming fewer alcoholic beverages than men, liking patterns in the two genders were similar. Three liking patterns for different alcoholic beverages largely driven by orosensory properties were identified in both genders. “Spirit-lovers” constituted the smallest group (12%), consumed alcoholic beverages of any kind (not only spirits) more than the other segments, and were mainly men aged 30–45. “Beer/wine lovers” (44%) were the oldest group with no difference by gender. “Mild-drink lovers” (44%) liked alcoholic drinks with intense sweet taste and/or mixers that moderate ethanol perception. They were mainly women, aged 18–29, had a lower consumption of alcohol, and a higher orosensory responsiveness than the other two groups. The results also suggest the opportunity to develop personalized recommendations towards specific consumer segments based not only on socio-demographics but considering also perceptive variables. Finally, our data suggest that increased burning and bitterness from alcohol may act as a sensory hindrance to alcoholic beverage overconsumption.
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Tekeste, Mehari Z., Loran R. Balvanz, Firas Al-Aani, Adam Boesenberg, and Jerry L. Hatfield. "Hardened Edges Effects on Wear Characteristics of Cultivator Sweeps Using Circular Soil Bin Test." Journal of Tribology 144, no. 2 (2021). http://dx.doi.org/10.1115/1.4050805.
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Abstract Tillage tools are subject to friction and low-stress abrasive wear processes with the potential deterioration of the desired soil quality, loss of mechanical weed efficacy, and downtime for replacing worn tools. Limited experimental methods exist to quantify investigate the effect of wear-resistant coatings on shape parameters of soil-engaging tools. ASTM standard sand/rubber wheel abrasion and pin-on-disk tests are not able to simulate wear characteristics of the complex shape of the tillage tools. Even though the tribology of tillage tools can be realistic from field tests, tillage wear tests under field conditions are expensive and often challenging to generate repeatable engineering data due to variable soil conditions in the field. A technique that simulated tillage wear of cultivator sweep in a circular soil bin filled with abrasive gravel medium and moisture condition was developed and applied to quantify the wear characteristics of cultivator sweeps with and without hardfaced edges. The hardfaced cultivator sweep had a cemented carbide chip applied to the bottom cutting edge and front tip sections of a standard cultivator sweep according to a proprietary CADEN Edge welding process. The CADEN Edge hardfaced sweeps showed improved wear performance 1.7 times and 3.5 times on mass and shape (sweep length and sweep wing cutting width) dimensions, respectively, compared with the un-hardened standard sweep. The results implied hardfaced cultivator sweep with cemented carbide chips provide potential in maintaining tillage productivity and the desired soil quality for seed-bed preparation.
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Yang, Guang, Hongwei Guo, Hong Xiao, Huayi Jiang, and Rongqiang Liu. "Out-of-Plane Stiffness Analysis of Kevlar/Carbon Fiber Hybrid Composite Skins for a Shear Variable-Sweep Wing." Applied Composite Materials, July 26, 2021. http://dx.doi.org/10.1007/s10443-021-09926-7.
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