Journal articles on the topic 'Wings – Mathematical models'
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1
Alexander, R. McN. "Modelling approaches in biomechanics." Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences 358, no. 1437 (August 6, 2003): 1429–35. http://dx.doi.org/10.1098/rstb.2003.1336.
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Conceptual, physical and mathematical models have all proved useful in biomechanics. Conceptual models, which have been used only occasionally, clarify a point without having to be constructed physically or analysed mathematically. Some physical models are designed to demonstrate a proposed mechanism, for example the folding mechanisms of insect wings. Others have been used to check the conclusions of mathematical modelling. However, others facilitate observations that would be difficult to make on real organisms, for example on the flow of air around the wings of small insects. Mathematical models have been used more often than physical ones. Some of them are predictive, designed for example to calculate the effects of anatomical changes on jumping performance, or the pattern of flow in a 3D assembly of semicircular canals. Others seek an optimum, for example the best possible technique for a high jump. A few have been used in inverse optimization studies, which search for variables that are optimized by observed patterns of behaviour. Mathematical models range from the extreme simplicity of some models of walking and running, to the complexity of models that represent numerous body segments and muscles, or elaborate bone shapes. The simpler the model, the clearer it is which of its features is essential to the calculated effect.
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Kobelev, Vladimir. "Approximate static aeroelastic analysis of composite wings." Multidiscipline Modeling in Materials and Structures 15, no. 2 (February 21, 2019): 365–86. http://dx.doi.org/10.1108/mmms-02-2018-0019.
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PurposeThe purpose of this paper is to consider divergence of composite plate wings as well as slender wings with thin-walled cross-section of small-size airplanes. The main attention is paid to establishing of closed-form mathematical solutions for models of wings with coupling effects. Simplified solutions for calculating the divergence speed of wings with different geometry are established.Design/methodology/approachThe wings are modeled as anisotropic plate elements and thin-walled beams with closed cross-section. Two-dimensional plate-like models are applied to analysis and design problems for wings of large aspect ratio.FindingsAt first, the equations of elastic deformation for anisotropic slender, plate-like wing with the large aspect ratio are studied. The principal consideration is delivered to the coupled torsion-bending effects. The influence of anisotropic tailoring on the critical divergence speed of the wing is examined in closed form. At second, the method is extended to study the behavior of the large aspect ratio, anisotropic wing with box-like wings. The static equations of the wing with box-like profile are derived using the theory of anisotropic thin-walled beams with closed cross-section. The solutions for forward-swept wing with box-like profiles are given in analytical formulas. The formulas for critical divergence speed demonstrate the dependency upon cross-sectional shape characteristics and anisotropic properties of the wing.Research limitations/implicationsThe following simplifications are used: the simplified aerodynamic theory for the wings of large aspect ratio was applied; the static aeroelastic instability is considered (divergence); according to standard component methodology, only the component of wing was modeled, but not the whole aircraft; the simplified theories (plate-lime model for flat section or thin-walled beam of closed-section) were applied; and a single parameter that defines the rotation of a stack of single layers over the face of the wing.Practical implicationsThe simple, closed-form formulas for an estimation of critical static divergence are derived. The formulas are intended for use in designing of sport aircraft, gliders and small unmanned aircraft (drones). No complex analysis of airflow and advanced structural and aerodynamic models is necessary. The expression for chord length over the span of the wing allows for accounting a board class of wing shapes.Social implicationsThe derived theory facilitates the use of composite materials for popular small-size aircraft, and particularly, for drones and gliders.Originality/valueThe closed-form solutions for thin-walled beams in steady gas flow are delivered in closed form. The explicit formulas for slender wings with variable chord and stiffness along the wing span are derived.
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Zafirov, Dimo. "Electric vertical take-off and landing fixed wing unmanned aerial vehicle for long endurance or long range?" Aerospace Research in Bulgaria 31 (2019): 99–107. http://dx.doi.org/10.3897/arb.v31.e08.
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An analysis of requirements to electric vertical take-off and landing unmanned aerial vehicle with fixed wings is carried out in this article. These aircraft have to fulfil requirements of users and to be convenient for operation in any field conditions. Long flight duration and long flight range are important for most missions. Mathematical models for both cases are presented and it has been found that the requirements for the wing load are different. It is recommended to use a type of UAV (Unmanned Aerial Vehicle) that is modular and allows performing flights with different configurations and payload depending on the mission in order to fulfill these requirements.
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Mosunov, V. A., R. V. Ryabykina, V. I. Smyslov, and A. V. Frolov. "Experience of computational research on the flutter of an unmanned aerial vehicle." Journal of «Almaz – Antey» Air and Space Defence Corporation, no. 2 (June 30, 2018): 18–25. http://dx.doi.org/10.38013/2542-0542-2018-2-18-25.
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The paper focuses on the sequence of computational and experimental investigations on the flutter. We set the initial data for the unmanned aerial vehicle and built the mathematical models. Furthermore, we did parametric analysis of symmetric and antisymmetric flutter shapes of the wings and the tail, studied the aerodynamics effect on the body of the vehicle, gave the examples of the calculation data on the base of KS-M and MSC. Nastran software.
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Bayly, P. V., and S. K. Dutcher. "Steady dynein forces induce flutter instability and propagating waves in mathematical models of flagella." Journal of The Royal Society Interface 13, no. 123 (October 2016): 20160523. http://dx.doi.org/10.1098/rsif.2016.0523.
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Cilia and flagella are highly conserved organelles that beat rhythmically with propulsive, oscillatory waveforms. The mechanism that produces these autonomous oscillations remains a mystery. It is widely believed that dynein activity must be dynamically regulated (switched on and off, or modulated) on opposite sides of the axoneme to produce oscillations. A variety of regulation mechanisms have been proposed based on feedback from mechanical deformation to dynein force. In this paper, we show that a much simpler interaction between dynein and the passive components of the axoneme can produce coordinated, propulsive oscillations. Steady, distributed axial forces, acting in opposite directions on coupled beams in viscous fluid, lead to dynamic structural instability and oscillatory, wave-like motion. This ‘flutter’ instability is a dynamic analogue to the well-known static instability, buckling. Flutter also occurs in slender beams subjected to tangential axial loads, in aircraft wings exposed to steady air flow and in flexible pipes conveying fluid. By analysis of the flagellar equations of motion and simulation of structural models of flagella, we demonstrate that dynein does not need to switch direction or inactivate to produce autonomous, propulsive oscillations, but must simply pull steadily above a critical threshold force.
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Eshghi, Shahab, Vahid Nooraeefar, Abolfazl Darvizeh, Stanislav N. Gorb, and Hamed Rajabi. "WingMesh: A Matlab-Based Application for Finite Element Modeling of Insect Wings." Insects 11, no. 8 (August 18, 2020): 546. http://dx.doi.org/10.3390/insects11080546.
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The finite element (FE) method is one of the most widely used numerical techniques for the simulation of the mechanical behavior of engineering and biological objects. Although very efficient, the use of the FE method relies on the development of accurate models of the objects under consideration. The development of detailed FE models of often complex-shaped objects, however, can be a time-consuming and error-prone procedure in practice. Hence, many researchers aim to reach a compromise between the simplicity and accuracy of their developed models. In this study, we adapted Distmesh2D, a popular meshing tool, to develop a powerful application for the modeling of geometrically complex objects, such as insect wings. The use of the burning algorithm (BA) in digital image processing (DIP) enabled our method to automatically detect an arbitrary domain and its subdomains in a given image. This algorithm, in combination with the mesh generator Distmesh2D, was used to develop detailed FE models of both planar and out-of-plane (i.e., three-dimensionally corrugated) domains containing discontinuities and consisting of numerous subdomains. To easily implement the method, we developed an application using the Matlab App Designer. This application, called WingMesh, was particularly designed and applied for rapid numerical modeling of complicated insect wings but is also applicable for modeling purposes in the earth, engineering, mathematical, and physical sciences.
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bin Ibrahim, Mohamad Faizul, Ovinis Mark, and Kamarudin bin Shehabuddeen. "An Underwater Glider for Subsea Intervention: A Technical Feasibility Study." Applied Mechanics and Materials 393 (September 2013): 561–66. http://dx.doi.org/10.4028/www.scientific.net/amm.393.561.
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An underwater glider is a type of autonomous underwater vehicle that moves based on small changes in its buoyancy, maneuvering using it wings as it glides through the water. These gliders, currently used in oceanographic sampling, may potentially be used to deliver payloads for subsea intervention at a lower net transport economy (NTE). Net transport economy, is a measure of the cost of transport in terms of the energy consumed per meter traveled, for each kilogram of loaded mass in air or net buoyancy underwater. The current method of payload delivery is either by using customized support vessel or remotely operated vehicle. This paper presents a technical feasibility study of extending the use of these gliders for subsea intervention, with emphasis on payload delivery. Important aspects of an underwater glider such as its volume (size), speed, wing area, wing span, operational depth and net transport economy were considered. The analysis was based on mathematical models governing existing gliders such as legacy gliders and the XRAY Liberdade. The results obtained were validated by extrapolating the present state of the art in underwater gliders to the proposed future use of these gliders, which is for payload delivery. In conclusion, the use of underwater gliders for subsea intervention is feasible based on factors considered in this study.
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Jaworski, Justin W., and N. Peake. "Aeroacoustics of Silent Owl Flight." Annual Review of Fluid Mechanics 52, no. 1 (January 5, 2020): 395–420. http://dx.doi.org/10.1146/annurev-fluid-010518-040436.
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The ability of some species of owl to fly in effective silence is unique among birds and provides a distinct hunting advantage, but it remains a mystery as to exactly what aspects of the owl and its flight are responsible for this dramatic noise reduction. Crucially, this mystery extends to how the flow physics may be leveraged to generate noise-reduction strategies for wider technological application. We review current knowledge of aerodynamic noise from owls, ranging from live owl noise measurements to mathematical modeling and experiments focused on how owls may disrupt the standard routes of noise generation. Specialized adaptations and foraging strategies are not uniform across all owl species: Some species may not have need for silent flight, or their evolutionary adaptations may not be effective for useful noise reduction for certain species. This hypothesis is examined using mathematical models and borne out where possible by noise measurements and morphological observations of owl feathers and wings.
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Dececchi, T. Alexander, Hans C. E. Larsson, and Michael B. Habib. "The wings before the bird: an evaluation of flapping-based locomotory hypotheses in bird antecedents." PeerJ 4 (July 7, 2016): e2159. http://dx.doi.org/10.7717/peerj.2159.
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Background:Powered flight is implicated as a major driver for the success of birds. Here we examine the effectiveness of three hypothesized pathways for the evolution of the flight stroke, the forelimb motion that powers aerial locomotion, in a terrestrial setting across a range of stem and basal avians: flap running, Wing Assisted Incline Running (WAIR), and wing-assisted leaping.Methods:Using biomechanical mathematical models based on known aerodynamic principals and in vivo experiments and ground truthed using extant avians we seek to test if an incipient flight stroke may have contributed sufficient force to permit flap running, WAIR, or leaping takeoff along the phylogenetic lineage from Coelurosauria to birds.Results:None of these behaviours were found to meet the biomechanical threshold requirements before Paraves. Neither was there a continuous trend of refinement for any of these biomechanical performances across phylogeny nor a signal of universal applicability near the origin of birds. None of these flap-based locomotory models appear to have been a major influence on pre-flight character acquisition such as pennaceous feathers, suggesting non-locomotory behaviours, and less stringent locomotory behaviours such as balancing and braking, played a role in the evolution of the maniraptoran wing and nascent flight stroke. We find no support for widespread prevalence of WAIR in non-avian theropods, but can’t reject its presence in large winged, small-bodied taxa likeMicroraptorandArchaeopteryx.Discussion:Using our first principles approach we find that “near flight” locomotor behaviors are most sensitive to wing area, and that non-locomotory related selection regimes likely expanded wing area well before WAIR and other such behaviors were possible in derived avians. These results suggest that investigations of the drivers for wing expansion and feather elongation in theropods need not be intrinsically linked to locomotory adaptations, and this separation is critical for our understanding of the origin of powered flight and avian evolution.
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Aideo, Swati N., and Dambarudhar Mohanta. "Unusually diverse surface-wettability features found in the wings of butterflies across Lepidoptera order and evaluation of generic and vertical gibbosity-based models." Physica Scripta 96, no. 8 (May 14, 2021): 085004. http://dx.doi.org/10.1088/1402-4896/abe82e.
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Klein Heerenbrink, M., L. C. Johansson, and A. Hedenström. "Power of the wingbeat: modelling the effects of flapping wings in vertebrate flight." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 471, no. 2177 (May 2015): 20140952. http://dx.doi.org/10.1098/rspa.2014.0952.
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Animal flight performance has been studied using models developed for man-made aircraft. For an aeroplane with fixed wings, the energetic cost as a function of flight speed can be expressed in terms of weight, wing span, wing area and body area, where more details are included in proportionality coefficients. Flying animals flap their wings to produce thrust. Adopting the fixed wing flight model implicitly incorporates the effects of wing flapping in the coefficients. However, in practice, these effects have been ignored. In this paper, the effects of reciprocating wing motion on the coefficients of the fixed wing aerodynamic power model for forward flight are explicitly formulated in terms of thrust requirement, wingbeat frequency and stroke-plane angle, for optimized wingbeat amplitudes. The expressions are obtained by simulating flights over a large parameter range using an optimal vortex wake method combined with a low-level blade element method. The results imply that previously assumed acceptable values for the induced power factor might be strongly underestimated. The results also show the dependence of profile power on wing kinematics. The expressions introduced in this paper can be used to significantly improve animal flight models.
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Pupyshev, A. A. "Spectral interferences and their correction in atomic emission spectral analysis." Industrial laboratory. Diagnostics of materials 85, no. 1II) (February 15, 2019): 15–32. http://dx.doi.org/10.26896/1028-6861-2019-85-1-ii-15-32.
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The main sources of spectral interferences in atomic emission spectral analysis (AESA) are considered, including both wide-range (bremsstrahlung and recombination continuum, radiation of hot condensed particles and electrode ends, scattered light in the spectrometer, overlapping of the analytical line by the wings of the neighbor strong spectral lines of interfering elements, imposition of the components of molecular bands with the very close lines) and narrow-band (partial or complete overlapping of the analytical line with atomic or ionic lines of the sample elements, electrodes and discharge atmosphere; superposition of spectra from higher orders of reflection in conventional diffraction spectrometers and from neighboring orders in two-dimensional echelle spectrometers). The features of their manifestation in various sources of spectrum excitation (flames, DC arc, spark discharges, arc plasma discharges, inductively coupled plasma, microwave plasma, low-pressure electric discharges, laser spark) are considered. The possibilities of reducing the level of spectral interferences or elimination of the spectral noise at the stage of design and manufacturing of AESA devices, as well as upon selecting and adjusting of operation conditions of the analysis are shown. Much attention is paid to the most easily implemented in practice off-peak correction of wide-range spectral interferences. The modern methods of background correction under the spectral peak (under-peak) using a software for atomic emission spectrometers and providing creation of various mathematical models of the background signal in the vicinity of the analytical line at the stage of developing a specific AESA technique are considered. The issues of the choice of spectral lines for analytical measurements, tables and atlases of spectral lines, electronic databases used for this purpose are considered in detail. Specific features of application of the method of inter-element correction with direct spectral overlapping of the lines are given. The operating sequence for taking into account spectral interferences when developing the analysis techniques is proposed.
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Betyaev, S. K., and O. P. Brysov. "Mathematical models and topological methods in wing aerodynamics." Journal of Applied Mechanics and Technical Physics 36, no. 1 (January 1995): 38–44. http://dx.doi.org/10.1007/bf02369671.
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Berci, Marco. "On Aerodynamic Models for Flutter Analysis: A Systematic Overview and Comparative Assessment." Applied Mechanics 2, no. 3 (July 29, 2021): 516–41. http://dx.doi.org/10.3390/applmech2030029.
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This work reviews different analytical formulations for the time-dependent aerodynamic load of a thin aerofoil and clarifies numerical flutter results available in the literature for the typical section of a flexible wing; inviscid, two-dimensional, incompressible, potential flow is considered in all test cases. The latter are investigated using the exact theory for small airflow perturbations, which involves both circulatory and non-circulatory effects of different nature, complemented by the p-k flutter analysis. Starting from unsteady aerodynamics and ending with steady aerodynamics, quasi-unsteady and quasi-steady aerodynamic models are systematically derived by successive simplifications within a unified approach. The influence of the aerodynamic approximations on the aeroelastic stability boundary is then rigorously assessed from both physical and mathematical perspectives. All aerodynamic models are critically discussed and compared in the light of the numerical results as well, within a comprehensive theoretical framework in practice. In all cases, results accuracy depends on the aero-structural arrangement of the flexible wing; however, simplified unsteady and simplified quasi-unsteady aerodynamic approximations are suggested for robust flutter analysis whenever the wing’s elastic axis lies ahead of the aerofoil’s control point.
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Zhekov, Svetozar A., A. V. Myasnikov, and N. A. Belov. "Radiative colliding winds models: the stagnation point singularity." Symposium - International Astronomical Union 193 (1999): 402. http://dx.doi.org/10.1017/s0074180900205949.
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The singularity at the stagnation point in steady-state colliding winds has a big influence on the structure of the radiative interaction region. None of the existing numerical models treats properly this mathematical problem. As a result, all the available models cannot be used for deriving the stellar winds parameters by making a comparison with the observed X-ray properties.
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Xie, Liang, Han, Niu, Wei, Su, and Tang. "Experimental Study on Plasma Flow Control of Symmetric Flying Wing Based on Two Kinds of Scaling Models." Symmetry 11, no. 10 (October 9, 2019): 1261. http://dx.doi.org/10.3390/sym11101261.
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The symmetric flying wing has a simple structure and a high lift-to-drag ratio. Due to its complicated surface design, the flow field flowing through its surface is also complex and variable, and the three-dimensional effect is obvious. In order to verify the effect of microsecond pulse plasma flow control on the symmetric flying wing, two different sizes of scaling models were selected. The discharge energy was analyzed, and the force and moment characteristics of the two flying wings and the particle image velocimetry (PIV) results on their surface flow field were compared to obtain the following conclusions. The microsecond pulse surface dielectric barrier discharge energy density is independent of the actuator length but increases with the actuation voltage. After actuation, the stall angle of attack of the small flying wing is delayed by 4°, the maximum lift coefficient is increased by 30.9%, and the drag coefficient can be reduced by 17.3%. After the large flying wing is actuated, the stall angle of attack is delayed by 4°, the maximum lift coefficient is increased by 15.1%, but the drag coefficient is increased. The test results of PIV in the flow field of different sections indicate that the stall separation on the surface of the symmetric flying wing starts first from the outer side, and then the separation area begins to appear on the inner side as the angle of attack increases.
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Utomo, Rukmono Budi. "MODEL MATEMATIKA SEDERHANA REDAMAN GETARAN PADA SAYAP PESAWAT TERBANG." Jurnal Ilmiah Matematika dan Pendidikan Matematika 8, no. 1 (June 24, 2016): 8. http://dx.doi.org/10.20884/1.jmp.2016.8.1.2881.
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We have known that when the plane encountered turbulence or in a hard landing, the aircraft engine will swing to dampen vibrations of the aircraft wing. Thus, based on rights, this research is investigating and constructing mathematical model of aircraft wing vibration. In this research, we described not only the creation of mathematical models, but also the analysis of the model and its interpretation.
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TAKAHASHI, L., N. MAIDANA, W. FERREIRAJR, P. PULINO, and H. YANG. "Mathematical models for the dispersal dynamics: travelling waves by wing and wind." Bulletin of Mathematical Biology 67, no. 3 (May 2005): 509–28. http://dx.doi.org/10.1016/j.bulm.2004.08.005.
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Sen, Indrajit. "The effect of time-dilation on Bell experiments in the retrocausal Brans model." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 476, no. 2234 (February 2020): 20190546. http://dx.doi.org/10.1098/rspa.2019.0546.
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The possibility of using retrocausality to obtain a fundamentally relativistic account of the Bell correlations has gained increasing recognition in recent years. It is not known, however, the extent to which these models can make use of their relativistic properties to account for relativistic effects on entangled systems. We consider here a hypothetical relativistic Bell experiment, where one of the wings experiences time-dilation effects. We show that the retrocausal Brans model ( Found. Phys. , 49 (2), 2019) can be easily generalized to analyse this experiment, and that it predicts less separation of eigenpackets in the wing experiencing the time-dilation. This causes the particle distribution patterns on the photographic plates to differ between the wings—an experimentally testable prediction of the model. We discuss the difficulties faced by other hidden variable models in describing this experiment, and their natural resolution in our model due to its relativistic properties. In particular, we discuss how a ψ -epistemic interpretation may resolve several difficulties encountered in relativistic generalizations of de Broglie–Bohm theory and objective state reduction models. Lastly, we argue that it is not clear at present, due to technical difficulties, if our prediction is reproduced by quantum field theory. We conclude that if it is, then the retrocausal Brans model predicts the same result with great simplicity in comparison. If not, the model can be experimentally tested.
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Tang, J. H., J. Y. Su, C. H. Wang, and J. T. Yang. "Numerical Investigation of the Ground Effect for a Small Bird." Journal of Mechanics 29, no. 3 (May 9, 2013): 433–41. http://dx.doi.org/10.1017/jmech.2013.18.
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AbstractAn investigation with computational fluid dynamics of the ground effect on a small bird revealed quantitatively the obstruction of the vortex expansion resulting from the presence of the ground at varied distance. Preceding authors focused mainly on the bird's wings, generally neglecting the bird's body; we discuss specifically the distinction of the aerodynamic effect between cases with and without the presence of the bird's body. The results of simulation show that, considering only two wings, for a distance between the wing model and the ground smaller than a semi-span, the smaller is the ground clearance, the more significant is the ground effect. At clearance 0.37 times a semi-span, the drag is decreased 11%, and the lift is increased 5.6%. The ground effect for an intact bird model composed of both wings and body is less effective than that for a simplified model with body omitted, because a suction was observed on the lower surface of the intact bird's trunk at clearance 0.37 times a semi-span; for this reason the intact bird model benefits less from the ground effect than the model with body excluded, but increased lift and decreased drag remain observable. This research treating the ground effect on a gliding bird reveals the importance of the presence of the bird's body in both computational and experimental models.
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Ren, Hong Ying, Pei Ting Sun, Tong Li, Gui Tao Wu, and Lian Zhong Huang. "Simulation on Disturbance Characteristics of Marine Diesel Engine with Wing-Assisted System." Advanced Materials Research 347-353 (October 2011): 3564–70. http://dx.doi.org/10.4028/www.scientific.net/amr.347-353.3564.
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In order to research on the disturbance characteristics of marine diesel engine with wing-assisted system, mathematical models of ship, diesel engine, propeller and wing were established. Disturbance characteristics of marine diesel engine which using the wing-assisted system was simulated by matlab/simulink software. The output torque and speed curves of the marine diesel engine at different conditions were obtained, by inputting different wing thrust fluctuation signal. The results can provide some reference value to the wing-assisted technology in the application of ocean transport ships, and which has a certain dominating significance for dynamic coupling of diesel-wing ship.
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Chen, Chun Ping, Chuan Sheng Wang, and Meng Zhang. "Dynamic Simulation of 3D Fluid Field for Four-Wing Synchronous Mixer Rotor and Four-Wing Asynchronous Mixer Rotor." Key Engineering Materials 501 (January 2012): 76–81. http://dx.doi.org/10.4028/www.scientific.net/kem.501.76.
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The physical, mathematical and finite element models for the four-wing synchronous rotors and four-wing asynchronous rotors in internal mixer were established in this paper. By comparative analysis of the two types of processes involved in mixing process the pressure field, the velocity field and the concentration field, the viscosity field and the mixed exponential distribution on its 3D fluid field dynamic simulation were computed by the polyflow software. The results showed that the four-wing synchronous rotors were better than the four-wing asynchronous rotors in a number of performance parameters.
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PETROV, VALKO, and CHRISTOF AEGERTER. "INTEGRATING MECHANICAL CONTROL THEORY INTO MODELS OF BIOLOGICAL DEVELOPMENT — ANALYTICAL REVIEW." Journal of Mechanics in Medicine and Biology 11, no. 04 (September 2011): 713–34. http://dx.doi.org/10.1142/s0219519411004162.
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This paper presents both a general review on developmental biomechanics and a concrete proposition for the computation of a symmetry breaking instability of a model of biological development in terms of self-organization theory. The necessary biological and physical facts taken from the literature are described and discussed in the context of a unified statement of the problems for mathematical modeling of pattern formation. This is then applied to planar cell polarization (PCP) of the Drosophila wing. In this way, the process is modeled by an elastopolarization equation. In terms of this statement, the mechanical specificity (interaction with basal plate) of wing PCP is characterized. Some aspects of modeling somite formation as well as other developmental processes are also concerned.
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Spencer, S. J., and L. E. Cram. "Magnetic Field Generation by Galactic Winds." Symposium - International Astronomical Union 157 (1993): 357–65. http://dx.doi.org/10.1017/s007418090017442x.
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A new mechanism is presented for the local amplification and possible global dynamo maintenance of non-axisymmetric large-scale magnetic fields in disk galaxies. Shear in a galactic wind or large-scale flow of ionised gas with components axial and radial to the disk plane may regenerate large-scale magnetic fields.Numerical results are presented from kinematic mathematical models based on a local (thin disk) approximation and an exact three-dimensional formulation. The one-dimensional thin-disk model illustrates the possibility of exponential amplification and the resulting local axial spatial structure of large-scale galactic magnetic fields. Three-dimensional results support the possibility of global wind dynamo action.
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Madangopal, Rajkiran, Zaeem A. Khan, and Sunil K. Agrawal. "Biologically Inspired Design Of Small Flapping Wing Air Vehicles Using Four-Bar Mechanisms And Quasi-steady Aerodynamics." Journal of Mechanical Design 127, no. 4 (October 4, 2004): 809–16. http://dx.doi.org/10.1115/1.1899690.
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In this paper, the energetics of a flapping wing micro air vehicle is analyzed with the objective of design of flapping wing air vehicles. The salient features of this study are: (i) design of an energy storage mechanism in the air vehicle similar to an insect thorax which stores part of the kinetic energy of the wing as elastic potential energy in the thorax during a flapping cycle; (ii) inclusion of aerodynamic wing models using blade element theory and inertia of the mechanism using rigid body modeling techniques; (iii) optimization of parameters of the energy storage mechanism using the dynamic models so that the peak power input from the external actuators during a flapping cycle is minimized. A series of engineering prototypes based on these studies have been fabricated which justify the use of these mathematical techniques.
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O. T., Bolaji, Olalusi A. P., and Adesina B. S. "Mathematical Modeling of Drying Pattern of Ogi Produced From Two Types of Maize Grain." Journal of Food Research 4, no. 1 (December 29, 2014): 174. http://dx.doi.org/10.5539/jfr.v4n1p174.
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<p>This paper presents thin layer modeling of <em>ogi</em> produced from yellow and white maize at varying soaking period and dried in the cabinet and oven at 50 ºC. The moisture decrease for cabinet dried o<em>gi</em> produced from white maize from 49.0 11.5%, 49.5 to 11.32%, 46.5 to 12.33% and 46.12.29%. The drying rate for both oven and cabinet dried <em>ogi</em> produced from yellow maize decreased from 4.6 to 0.0525 kg/min, 4.5 to 0.0513 kg/min, 4.35 to 0.049 kg/min and 4.4 to 0.047 kg/min while for oven dried <em>ogi</em> followed a similar trend. The experimental data obtained were fitted to five thin layer models: Newton, Page, Herderson and Pabis, Two term and Wingh and Singh models. The values obtained for <em>ogi</em> produced from white maize and dried in the cabinet and oven at 50 ºC for Newton model gave a lower R<sup>2</sup>, ?<sup>2</sup>, RMSE compared with respective values obtained from Page, Herderson and Pabis, two term, Wing and Singh models. The two terms model appear to be the best model among the five models used in this work and had higher R<sup>2</sup>, lower ?<sup>2</sup>, and RMSE. The <em>ogi</em> produced from yellow maize at varying soaking period of 24, 48, 72 and 96 hours and dried in cabinet dryer and fitted with two term showed model constants a, K<sub>0,</sub> b, K<sub>1</sub> 0.04315, 0.0388995, 0.919, 2.2 × 10<sup>-3</sup> while the R<sup>2</sup>, ?<sup>2 </sup>RMSE were 0.9933, 5.85 × 10<sup>-4</sup> and 4.85 × 10<sup>5 </sup>for <em>ogi</em> produced for 24 hours soaking, respectively. The soaking period does not seem to affect the moisture ratio and the thin layer drying model. However, the initial moisture and equipment seems to affect significantly.</p>
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Fonzi, N., S. L. Brunton, and U. Fasel. "Data-driven nonlinear aeroelastic models of morphing wings for control." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 476, no. 2239 (July 2020): 20200079. http://dx.doi.org/10.1098/rspa.2020.0079.
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Accurate and efficient aeroelastic models are critically important for enabling the optimization and control of highly flexible aerospace structures, which are expected to become pervasive in future transportation and energy systems. Advanced materials and morphing wing technologies are resulting in next-generation aeroelastic systems that are characterized by highly coupled and nonlinear interactions between the aerodynamic and structural dynamics. In this work, we leverage emerging data-driven modelling techniques to develop highly accurate and tractable reduced-order aeroelastic models that are valid over a wide range of operating conditions and are suitable for control. In particular, we develop two extensions to the recent dynamic mode decomposition with control (DMDc) algorithm to make it suitable for flexible aeroelastic systems: (1) we introduce a formulation to handle algebraic equations, and (2) we develop an interpolation scheme to smoothly connect several linear DMDc models developed in different operating regimes. Thus, the innovation lies in accurately modelling the nonlinearities of the coupled aerostructural dynamics over multiple operating regimes, not restricting the validity of the model to a narrow region around a linearization point. We demonstrate this approach on a high-fidelity, three-dimensional numerical model of an airborne wind energy system, although the methods are generally applicable to any highly coupled aeroelastic system or dynamical system operating over multiple operating regimes. Our proposed modelling framework results in real-time prediction of nonlinear unsteady aeroelastic responses of flexible aerospace structures, and we demonstrate the enhanced model performance for model predictive control. Thus, the proposed architecture may help enable the widespread adoption of next-generation morphing wing technologies.
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Donkoh, Elvis Kobina, Rebecca Davis, Emmanuel D. J. Owusu-Ansah, Emmanuel A. Antwi, and Michael Mensah. "Application of Combinatorial Techniques to the Ghanaian Board Game Zaminamina Draft." European Journal of Pure and Applied Mathematics 12, no. 1 (January 31, 2019): 159–75. http://dx.doi.org/10.29020/nybg.ejpam.v12i1.3308.
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Games happen to be a part of our contemporary culture and way of life. Often mathematical models of conflict and cooperation between intelligent rational decision-makers are studied in these games. Example is the African board game ’Zaminamina draft’ which is often guided by combinatorial strategies and techniques for winning. In this paper we deduce an intelligent mathematical technique for playing a winning game. Two different starting strategies were formulated; center starting and edge or vertex starting. The results were distorted into a 3x3 matrix and elementary row operations were performed to establish all possible wins. MatLab was used to distort the matrix to determine the diagonal wins. A program was written using python in artificial intelligence (AI) to help in playing optimally
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Zlenko, Nikolay Alekseevich, Evgenii Sergeevich Matyash, Sergey Vladimirovich Mikhaylov, and Andrey Aleksandrovich Savelyev. "EMPIRICAL MATHEMATICAL MODELS IN OPTIMAL DESIGN OF THE ENGINE NACELLE SUSPENSION UNIT UNDER AN AIRCRAFT WING." TsAGI Science Journal 49, no. 2 (2018): 175–90. http://dx.doi.org/10.1615/tsagiscij.2018027031.
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Bose, S. K., P. Ray, and B. K. Dutta. "Mathematical Models for Mixing and Dispersion in Forecasting and Management of Estuarine Water Quality." Water Science and Technology 19, no. 9 (September 1, 1987): 183–93. http://dx.doi.org/10.2166/wst.1987.0079.
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The dispersion or spread of a dissolved or suspended substance in an estuarine system occurs mainly due to the non-uniformity of velocity distribution, including turbulent fluctuations, shear stress at the boundary and surface stress caused by winds. The mixing and dispersion phenomena in rivers and estuaries are extremely important in water quality management and control. The development of a dispersion model in harmony with the nature of the flow field in a river or estuary is necessary in the estimation and correlation of dispersion parameters, called dispersion coefficients, which may, in general, be anisotropic in a multidimensional transport process. The earlier one-dimensional models have gradually given way to higher dimensional models for better description of the phenomena as well as for more accurate estimation of parameters. Field studies of dispersion of tracers have been the most important method of generating data for parameter estimation. A number of correlations for mixing and dispersion coefficients in terms of flow rates and other fundamental system parameters are available. The present study incorporates the analysis, assessment and applications of various dispersion and mixing models available. Also, a critical appraisal of the validity, inherent degree of uncertainty and the range of applications of different correlations has been incorporated.
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Ganesh A, Deiva. "A Nonlinear Model to Study Selectively Deformable Wing of an Aircraft." IAES International Journal of Robotics and Automation (IJRA) 4, no. 4 (December 1, 2015): 316. http://dx.doi.org/10.11591/ijra.v4i4.pp316-325.
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<p>Aeroelasticity of an aircraft includes the study of dynamics of prime movers, structural dynamics, and aerodynamics. Research efforts are on in every area to improve the overall performance of an aircraft. In this paper preliminary studies conducted on the dynamics of selectively deformable wing using an under actuated nonlinear model is reported. First, the literature related to the design and analysis of selectively deformable structure (SDS) wing is reviewed. Second, a single degree of freedom (DOF) model to represent a fixed wing and a two DOF under-actuated model to represent SDS are discussed and their mathematical models are derived. Third, the effect of deformable wing portion on the wing dynamics is studied by varying the excitation frequency and stiffness of the model. Fourth, an experimental setup consisting of two rigid links connected by spring and subjected to sinusoidal displacement is investigated. Final section summarizes the research and provides directions for future work.</p>
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Ma, Zhenyu, Xiaoping Zhu, and Zhou Zhou. "Taxiing Characteristic Analysis and Control for Full-Wing Solar-Powered Unmanned Aerial Vehicle." Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University 37, no. 1 (February 2019): 7–12. http://dx.doi.org/10.1051/jnwpu/20193710007.
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To solve the taxiing control problem of the full-wing solar-powered unmanned aerial vehicle (UAV) without front wheel steering servo and rudder, a control approach using differential propeller thrust to control the taxiing is proposed in this paper. Firstly, the taxiing mathematical models of two kinds of full-wing solar-powered UAVs with the front wheels turning freely or fixed are established. Meanwhile, the taxiing characteristics of full-wing solar-powered UAV in different taxiing speeds are analyzed. Secondly, based on the linear active disturbance rejection control (LADRC) theory, a yaw angle controller is designed by using differential propeller thrust as the control output. Finally, a straight line trajectory tracking scheme which is suitable for take-off and landing taxiing is designed on the base of improved vector field theory. Simulation results show that the designed controller has a good control effect on full-wing solar-powered UAV's take-off and landing taxiing periods, and better robustness.
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Alam, MD Erfanul, Dazhong Wu, and Andrew K. Dickerson. "Predictive modelling of drop ejection from damped, dampened wings by machine learning." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 476, no. 2241 (September 2020): 20200467. http://dx.doi.org/10.1098/rspa.2020.0467.
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The high frequency, low amplitude wing motion that mosquitoes employ to dry their wings inspires the study of drop release from millimetric, forced cantilevers. Our mimicking system, a 10-mm polytetrafluoroethylene cantilever driven through ±1 mm base amplitude at 85 Hz, displaces drops via three principal ejection modes: normal-to-cantilever ejection, sliding and pinch-off. The selection of system variables such as cantilever stiffness, drop location, drop size and wetting properties modulates the appearance of a particular ejection mode. However, the large number of system features complicate the prediction of modal occurrence, and the transition between complete and partial liquid removal. In this study, we build two predictive models based on ensemble learning that predict the ejection mode, a classification problem, and minimum inertial force required to eject a drop from the cantilever, a regression problem. For ejection mode prediction, we achieve an accuracy of 85% using a bagging classifier. For inertial force prediction, the lowest root mean squared error achieved is 0.037 using an ensemble learning regression model. Results also show that ejection time and cantilever wetting properties are the dominant features for predicting both ejection mode and the minimum inertial force required to eject a drop.
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Spedding, G. R. "Comparing fluid mechanics models with experimental data." Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences 358, no. 1437 (August 12, 2003): 1567–76. http://dx.doi.org/10.1098/rstb.2003.1352.
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The art of modelling the physical world lies in the appropriate simplification and abstraction of the complete problem. In fluid mechanics, the Navier–Stokes equations provide a model that is valid under most circumstances germane to animal locomotion, but the complexity of solutions provides strong incentive for the development of further, more simplified practical models. When the flow organizes itself so that all shearing motions are collected into localized patches, then various mathematical vortex models have been very successful in predicting and furthering the physical understanding of many flows, particularly in aerodynamics. Experimental models have the significant added convenience that the fluid mechanics can be generated by a real fluid, not a model, provided the appropriate dimensionless groups have similar values. Then, analogous problems can be encountered in making intelligible but independent descriptions of the experimental results. Finally, model predictions and experimental results may be compared if, and only if, numerical estimates of the likely variations in the tested quantities are provided. Examples from recent experimental measurements of wakes behind a fixed wing and behind a bird in free flight are used to illustrate these principles.
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Jean Ross, A., and Geraldine F. Edwards. "Correlation of predicted and free-flight responses near departure conditions of a high incidence research model." Aeronautical Journal 91, no. 909 (November 1987): 397–405. http://dx.doi.org/10.1017/s0001924000021631.
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Summary The mathematical model of aerodynamic forces and moments is described, based on results from various wind-tunnel experiments with the RAE High Incidence Research Model (HIRM). Simulations of the responses due to longitudinal and lateral control inputs at high angles of attack are compared with the responses measured on free-flight models of the configuration. It is shown that the main features of the flight behaviour are reproduced, in particular such phenomena as roll-off, wing rock and nose slice.
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Lewicka, Marta, L. Mahadevan, and Mohammad Reza Pakzad. "Models for elastic shells with incompatible strains." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 470, no. 2165 (May 8, 2014): 20130604. http://dx.doi.org/10.1098/rspa.2013.0604.
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The three-dimensional shapes of thin lamina, such as leaves, flowers, feathers, wings, etc., are driven by the differential strain induced by the relative growth. The growth takes place through variations in the Riemannian metric given on the thin sheet as a function of location in the central plane and also across its thickness. The shape is then a consequence of elastic energy minimization on the frustrated geometrical object. Here, we provide a rigorous derivation of the asymptotic theories for shapes of residually strained thin lamina with non-trivial curvatures, i.e. growing elastic shells in both the weakly and strongly curved regimes, generalizing earlier results for the growth of nominally flat plates. The different theories are distinguished by the scaling of the mid-surface curvature relative to the inverse thickness and growth strain, and also allow us to generalize the classical Föppl–von Kármán energy to theories of prestrained shallow shells.
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Antonenko, Mikhail, Tatiana Guguchkina, Olga Antonenko, Alla Abakumova, and Anton Khrapov. "Research of mechanisms of transformation and removal of antibiotics from wine by sorbents of different nature." BIO Web of Conferences 34 (2021): 06006. http://dx.doi.org/10.1051/bioconf/20213406006.
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On the basis of own research, the authors experimentally confirmed the reliability of the hypothesis expressed in the scientific literature about the possibility of effective removal of nisin and natamycin from wines and wine materials. New knowledge has been obtained about the possible mechanisms of sorption of nisin and natamycin through the use of sorbents of various nature. Comparative experimental data on the interaction of sorbents with antibiotics in wines are presented. In this work, experimental data are presented that indicate different efficiency of antibiotic removal during wine processing, which is due to the structure and properties of sorbents. It has been shown that the sorption capacity of sorbents for natamycin and nisin decreases in the series: activated carbon, bentonite, and colloidal silicon dioxide. Mathematical models have been obtained for decontamination of antibiotics from wine production using sorbents of various nature.
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Tan, Szu-Ying, and C. Edward Lan. "Frequency-Domain Optimal Estimator for Wing Rock Models." Journal of Guidance, Control, and Dynamics 20, no. 4 (July 1997): 748–53. http://dx.doi.org/10.2514/2.4107.
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Benaim, Shalom, and Peter Friz. "Smile Asymptotics II: Models with Known Moment Generating Functions." Journal of Applied Probability 45, no. 01 (March 2008): 16–32. http://dx.doi.org/10.1017/s0021900200003922.
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The tail of risk neutral returns can be related explicitly with the wing behaviour of the Black-Scholes implied volatility smile. In situations where precise tail asymptotics are unknown but a moment generating function is available we establish, under easy-to-check Tauberian conditions, tail asymptotics on logarithmic scales. Such asymptotics are enough to make the tail-wing formula (see Benaim and Friz (2008)) work and so we obtain, under generic conditions, a limiting slope when plotting the square of the implied volatility against the log strike, improving a lim sup statement obtained earlier by Lee (2004). We apply these results to time-changed exponential Lévy models and examine several popular models in more detail, both analytically and numerically.
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Benaim, Shalom, and Peter Friz. "Smile Asymptotics II: Models with Known Moment Generating Functions." Journal of Applied Probability 45, no. 1 (March 2008): 16–32. http://dx.doi.org/10.1239/jap/1208358948.
Full textAbstract:
The tail of risk neutral returns can be related explicitly with the wing behaviour of the Black-Scholes implied volatility smile. In situations where precise tail asymptotics are unknown but a moment generating function is available we establish, under easy-to-check Tauberian conditions, tail asymptotics on logarithmic scales. Such asymptotics are enough to make the tail-wing formula (see Benaim and Friz (2008)) work and so we obtain, under generic conditions, a limiting slope when plotting the square of the implied volatility against the log strike, improving a lim sup statement obtained earlier by Lee (2004). We apply these results to time-changed exponential Lévy models and examine several popular models in more detail, both analytically and numerically.
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Sakhnenko, O. I. "Results of calculation of wave-wind water dynamics at the Tiligul Estuary." Ukrainian hydrometeorological journal, no. 18 (October 29, 2017): 140–49. http://dx.doi.org/10.31481/uhmj.18.2016.16.
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Features of spatial distribution of the main parameters of wind waves, such as height, average orbital velocities of wave motions determining transportation of bottom material were specified. Maximum heights of significant waves were obtained in the central, most deep-water part of the estuary, as well as in the southern part and near the windward shores. At the time of storm winds maximum heights of significant waves, according to the simulation results, constitute up to 0,83 m. On the basis of calculations of wind waves with application of the SWAN numerical model (Simulating Waves Nearshore) made using wind observations during 2012, regime functions of wind waves’ heights for different parts of the estuary were built. Statistical estimates of wind waves’ heights at typical points of the estuary waters were analyzed. Spatial fields of wind-wave flows in the estuary under the influence of steady winds of the southern and western directions calculated using the complex of numerical mathematical models of wind wave generation and models of wind-wave water circulation based on Reynolds equations and supplemented with com-ponents of the wave radiation stresses were specified.
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En Chao, Joshua Jang. "Extractor X — Autonomous Tilt Rotor UAV." Unmanned Systems 01, no. 02 (October 2013): 177–98. http://dx.doi.org/10.1142/s2301385013400025.
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This paper looks into conceptualization, implementation and validation of the potential role that hybrid quad tilt rotor unmanned aerial vehicles (UAV) may undertake in the near future, especially so in military applications. A tilt rotor is designed, built and analyzed with wind tunnel data, theoretical calculations and flight log data. In addition, the paper will discuss the flight mechanics involved during its transition from hover to forward flight. As the tandem wing tilt rotor encompasses two unconventional designs, numerous mathematical models were developed in the design of the UAV.
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Yoshioka, S., T. Nakano, Y. Nozue, and S. Kinoshita. "Coloration using higher order optical interference in the wing pattern of the Madagascan sunset moth." Journal of The Royal Society Interface 5, no. 21 (November 13, 2007): 457–64. http://dx.doi.org/10.1098/rsif.2007.1268.
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Colour patterns of animals' bodies are usually produced by the spatial distribution of pigments with different colours. However, some animals use the spatial variation of colour-producing microstructures. We have studied one distinctive example of such structurally produced colour patterns, the wing of the Madagascan sunset moth, to clarify the physical rules that underlie the colour variation. It is known that the iridescent wing scale of the sunset moth has the alternate air–cuticle multilayer structure that causes optical interference. The microscopic and optical investigations of various parts of the wing have confirmed that the thickness of the cuticle layers within the scale largely varies to produce the colour pattern. However, it varies in very different ways between the dorsal and ventral sides of the hind wing; the thickness gradually varies on the dorsal side from scale to scale, while the abrupt changes are found on the ventral side to form distinctive borders between differently coloured areas. It is also revealed that an unusual coloration mechanism is involved in the green part of the ventral hind wing: the colour is caused by higher order optical interference of the highly non-ideal multilayer structure. The physical mechanism of the colour pattern formation is briefly discussed with the several mathematical models proposed so far.
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Lancellotti, Lisa, Simona Sighinolfi, Andrea Marchetti, and Lorenzo Tassi. "Use of Lead Isotopic Ratios as Geographical Tracer for Lambrusco PDO Wines." Molecules 25, no. 7 (April 2, 2020): 1641. http://dx.doi.org/10.3390/molecules25071641.
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In this study, the lead isotope signature was tested with the aim to verify its potential as geographic tracer for wine production and particularly for the Lambrusco PDO wines of the province of Modena (Italy). A solid phase extraction procedure, for separating lead from the investigated matrices, soil and wine, was optimized. Furthermore, different mathematical models, based on an exponential law and internal or external correction approach, were evaluated for the correction of instrumental mass dependent fractionation. The optimized analytical procedure yielded isotopic ratio data relative to the lead NIST 981 standard, 208Pb/206Pb = 2.16664 and 207Pb/206Pb = 0.914645, in good agreement both with the tabulated values and with the most recent literature data. Measured isotope ratio data highlight the contribute of multiple lead sources in bottled wine but different from the one present in soils.
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Meng, Guang Lei. "Control Architecture and Control Laws Design for Multiple UAVs Formation Flight." Applied Mechanics and Materials 246-247 (December 2012): 853–57. http://dx.doi.org/10.4028/www.scientific.net/amm.246-247.853.
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An autonomous formation-flight method for multiple UAVs (Unmanned Aerial Vehicle) was designed. First the mathematical representation of formation shape was analyzed. Then the control architecture was devised for multiple UAVs formation flight based on finite state machine. The flight states of the wing UAV were built through the formation flight and the transformation relationships of these flight states were defined. So the automated transformation among these flight states could be achieved and the intelligence of the pilots could be mimicked by this way. Aiming at the typical flight state which is capable of maintaining the formation shape, the control laws were contrived for the wing UAVs. Finally, two nonlinear fighter models which have 6 degrees of freedom were selected to carry out autonomous formation-flight experiments. And the results show the control laws designed for maintaining the formation shape are valid.
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Santana, Juan J., Víctor Cano, Helena C. Vasconcelos, and Ricardo M. Souto. "The Influence of Test-Panel Orientation and Exposure Angle on the Corrosion Rate of Carbon Steel. Mathematical Modelling." Metals 10, no. 2 (January 29, 2020): 196. http://dx.doi.org/10.3390/met10020196.
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The effects of both test-panel orientation and exposure angle on the atmospheric corrosion rates of carbon steel probes exposed to a marine atmosphere were investigated. Test samples were exposed in a tree-shape metallic frame with either three exposure angles of 30°, 45° and 60° and orientation north-northeast (N-NE), or eight different orientation angles around a circumference. It was found that the experimental corrosion rates of carbon steel decreased for the specimens exposed with greater exposure angles, whereas the highest corrosion rates were found for those oriented to N-NE due to the influence of the prevailing winds. The obtained data obtained were fitted using the bi-logarithmic law and its variations as to take in account the amounts of pollutants and the time of wetness (TOW) for each particular case with somewhat good agreement, although these models failed when all the effects were considered simultaneously. In this work, we propose a new mathematical model including qualitative variables to account for the effects of both exposure and orientation angles while producing the highest quality fits. The goodness of the fit was used to determine the performance of the mathematical models.
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Тиняков, Дмитрий Васильевич, and Виктор Иванович Рябков. "МЕТОД ПОПЕРЕДНЬОГО ФОРМУВАННЯ ОСНОВНИХ ПАРАМЕТРІВ ПІД ЧАС ГЛИБОКИХ МОДІФІКАЦІЙНИХ ЗМІН У ЛІТАКАХ ТРАНСПОРТНОЇ КАТЕГОРІЇ." Aerospace technic and technology, no. 7 (November 10, 2018): 62–67. http://dx.doi.org/10.32620/aktt.2018.7.09.
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The method of a preliminary development of main performances during deep variation in variants of a transport category aircraft, that is, when changing a wing area and a powerplant output, has been proposed. The main performance of any aircraft on the stage of its modifying is takeoff mass to, its value depends on structural members’ masses, in which modifications changes are present. The method is based on the com-parative evaluation of take-off mass increments of a basic aircraft and it’s variant. That allows qualitatively and quantitatively to evaluate the specific value of the take-off mass increment of an airplane variant depending on engineering and economical requirements changes. Also, it is obvious that changes in the combination of performances their changes in the process of an aircraft variant creation, move the solution of an existence equation at new point, which corresponds to a new takeoff mass. The analysis of the method was implemented on the example of the regional passenger aircraft variant with two turboprop engines. The method of a preliminary development of main performances of a transport category aircraft subject to deep modification, i.e. when changing a wing area or a powerplant output, is proposed. The mathematical model for the estimation of the takeoff mass increment, depending on requirement groups realized in modifications, is developed by using the models of calculation of required mass (due to change of modification) and available mass (constant for a base variant). Statistical equations for the preliminary estimation of a takeoff mass increment, that create the relationship between the constituent masses and the takeoff mass for a regional aircraft, are used. For middle-range and long-range airplanes an adjustment is needed. The proposed method and the mathematical models allow at a preliminary designing stage of an airplane variant not only typical required quantitative change in structure, but the necessary changes of a wing area and a powerplant output to satisfy the required engineering and economical requirements, which aircraft and air-lines’ markets dictate.
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Chen, Jiqing, Shaorong Xie, Jun Luo, and Hengyu Li. "Wind-driven land-yacht robot mathematical modeling and verification." Industrial Robot: An International Journal 43, no. 1 (January 18, 2016): 77–90. http://dx.doi.org/10.1108/ir-03-2015-0052.
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Purpose – The purpose of this paper was to solve the shortage of carrying energy in probing robot and make full use of wind resources in the Antarctic expedition by designing a four-wheel land-yacht. Land-yacht is a new kind of mobile robot powered by the wind using a sail. The mathematical model and trajectory of the land-yacht are presented in this paper. Design/methodology/approach – The mechanism analysis method and experimental modeling method are used to establish a dual-input and dual-output mathematical model for the motion of land-yacht. First, the land-yacht’s model structure is obtained by using mechanism analysis. Then, the models of steering gear, servomotors and force of wing sail are analyzed and validated. Finally, the motion of land-yacht is simulated according to the mathematical model. Findings – The mathematical model is used to analyze linear motion and steering motion. Compared with the simulation results and the actual experimental tests, the feasibility and reliability of the proposed land-yacht modeling are verified. It can travel according to the given signal. Practical implications – This land-yacht can be used in the Antarctic, outer planet or for harsh environment exploration. Originality/value – A land-yacht is designed, and the contribution of this research is the development of a mathematical model for land-yacht robot. It provides a theoretical basis for analysis of the land-yacht’s motion.
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Nardi, Tiziana, Maurizio Petrozziello, Raffaele Girotto, Michele Fugaro, Raffaele Antonio Mazzei, and Stefano Scuppa. "Wine aging authentication through Near Infrared Spectroscopy: a feasibility study on chips and barrel aged wines." OENO One 54, no. 1 (March 26, 2020): 165–73. http://dx.doi.org/10.20870/oeno-one.2020.54.1.2921.
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Aim: This research primarily focuses on exploring the suitability of near infrared (NIR) spectroscopy with multivariate data analysis as a tool to classify commercial wines depending on the aging process. It is aimed at discriminating between wines aged in barrels and those obtained using alternative products (chips).Methods and Results: Around 75 commercial barrel-aged red wines issued from the appellation “Valpolicella” (Italy) were analyzed. Moreover, 15 wines were aged at the experimental winery of the Research Centre of Viticulture and Enology in Asti using different types of commercial oak chips. Wines were analyzed in transmittance using NIR regions of the electromagnetic spectrum. Principal component analysis (PCA) and partial least squares (PLS) analyses were used to classify wines: a preliminary step was carried out using PCA that showed interesting groups in the whole data set. Next, in order to test if combined explanatory variables made it possible to discriminate treatments and how they are useful to predict which group a new observation will belong to, an orthogonal partial least squares discriminant analysis (OPLS-DA) was carried out. Several wine groups were considered, defined by factors including the aging process, the type of oak used for aging (wood barriques, barrels or chips) and the wine typologies (differing for some enological parameters).Conclusions: Overall, OPLS-DA models correctly classified >90 % of the wines. These results demonstrate the potential of combining spectroscopy with chemometric data analysis as a rapid method to classify wines according to their aging process. Nevertheless, the development of a mathematical model for predictive purposes is a complex task: indeed, large databases for different wines should be constructed, and other spectral IR zones might be evaluated for improving the method performance in determining wine aging process.Significance and impact of the study: This study contributes to the development of an easy-to-use and easily applicable NIR method for correlating the infrared “fingerprint” spectrum with the aging process in wines, aimed at implementing a technique able to discriminate wines aged with different wood types, that can be progressively used in the laboratory for routine fraud inspection.
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Taylor, Graham K., and Rafał Żbikowski. "Nonlinear time-periodic models of the longitudinal flight dynamics of desert locusts Schistocerca gregaria." Journal of The Royal Society Interface 2, no. 3 (May 18, 2005): 197–221. http://dx.doi.org/10.1098/rsif.2005.0036.
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Previous studies of insect flight control have been statistical in approach, simply correlating wing kinematics with body kinematics or force production. Kinematics and forces are linked by Newtonian mechanics, so adopting a dynamics-based approach is necessary if we are to place the study of insect flight on its proper physical footing. Here we develop semi-empirical models of the longitudinal flight dynamics of desert locusts Schistocerca gregaria . We use instantaneous force–moment measurements from individual locusts to parametrize the nonlinear rigid body equations of motion. Since the instantaneous forces are approximately periodic, we represent them using Fourier series, which are embedded in the equations of motion to give a nonlinear time-periodic (NLTP) model. This is a proper mathematical generalization of an earlier linear-time invariant (LTI) model of locust flight dynamics, developed using previously published time-averaged versions of the instantaneous force recordings. We perform various numerical simulations, within the fitted range of the model, and across the range of body angles used by free-flying locusts, to explore the likely behaviour of the locusts upon release from the tether. Solutions of the NLTP models are compared with solutions of the nonlinear time-invariant (NLTI) models to which they reduce when the periodic terms are dropped. Both sets of models are unstable and therefore fail to explain locust flight stability fully. Nevertheless, whereas the measured forces include statistically significant harmonic content up to about the eighth harmonic, the simulated flight trajectories display no harmonic content above the fundamental forcing frequency. Hence, manoeuvre control in locusts will not directly reflect subtle changes in the higher harmonics of the wing beat, but must operate on a coarser time-scale. A state-space analysis of the NLTP models reveals orbital trajectories that are impossible to capture in the LTI and NLTI models, and inspires the hypothesis that asymptotic orbital stability is the proper definition of stability in flapping flight. Manoeuvre control on the scale of more than one wing beat would then consist in exciting transients from one asymptotically stable orbit to another. We summarize these hypotheses by proposing a limit-cycle analogy for flapping flight control and suggest experiments for verification of the limit-cycle control analogy hypothesis.