Fanwing Aircraft- Scope as an Agricultural Aircraft

The objective of this paper is to apply the concept of fan wing to agricultural aircrafts which are conventionally fixed wings aircrafts or multi-rotor drones. Fan wing is capable of producing good amount of lift at a sufficiently low speed without stalling, thus is apt for agricultural processes of irrigation, spraying pesticides, etc. Fan wing has a special ability that it doesn’t stalls (for the practical range of AOA), making this spraying method reliable. A fanwing aircraft is modelled using CATIA V5 and the flow visualizations for the same are performed on the ANSYS. This aircraft is then compared with three different existing agricultural aircrafts on different parameters, namely payload capacity, work efficiency and ease of operation. The comparison shows that such fanwing vehicle is a good substitute over the conventional fixed wings and multi-rotor drones.

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Influence of Leading Edge Tubercles in an Annular Compressor Cascade With Different Hub-Tip Ratios and Aspect Ratios

Volume 2A: Turbomachinery ◽

10.1115/gt2017-64054 ◽

2017 ◽

Author(s):

Tan Zheng ◽

Mingmin Zhu ◽

Xiaoqing Qiang ◽

Jinfang Teng ◽

Jinzhang Feng

Keyword(s):

Numerical Study ◽

Incidence Angle ◽

Leading Edge ◽

Compressor Cascade ◽

Corner Separation ◽

Low Speed ◽

Passive Flow Control ◽

Passive Flow ◽

Aspect Ratios ◽

Flow Visualizations

Humpback whale flippers’ scalloped tubercles on the leading edge are thought to enhance the whale’s underwater maneuverability. Inspired by the flippers, leading edge tubercles are applied in a low speed annular compressor cascade as a type of passive flow control techniques in this paper. A numerical study is performed to investigate the influence of tubercles on the aerodynamic losses and corner separation in the low speed cascades. Different low speed cascades based on a CDA airfoil profile are built with several hub-tip ratios and aspect ratios. Steady RANS simulations are carried out for these cascades with and without leading edge tubercles. The aerodynamic performance and corner separation features are subsequently investigated in these cascades. The influence of tubercles under the variation of hub-tip ratio and aspect ratio is understood and concluded from the comparison of the performance attained by different cascades. Flow visualizations at a post-stall incidence angle show that the interaction between the tubercle-induced streamwise vortices and corner separation vortices plays a crucial role in attenuating the corner separation and reducing losses. By combining the performance analysis and flow visualizations, this paper discusses the mechanism of leading edge tubercles in a low speed annular compressor cascade with different hub-tip ratios and aspect ratios.

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New ultrastructural findings about Borrelia burgdorferi by cryofixation, negative staining, thin sectioning and scanning techniques

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100160467 ◽

1990 ◽

Vol 48 (3) ◽

pp. 582-583

Author(s):

S. F. Hayes ◽

M. D. Corwin ◽

T. G. Schwan ◽

D. W. Dorward ◽

W. Burgdorfer

Keyword(s):

Lyme Disease ◽

Borrelia Burgdorferi ◽

Structural Characterization ◽

Negative Staining ◽

Low Speed ◽

Thin Sectioning ◽

Ultrastructural Findings

Characterization of Borrelia burgdorferi strains by means of negative staining EM has become an integral part of many studies related to the biology of the Lyme disease organism. However, relying solely upon negative staining to compare new isolates with prototype B31 or other borreliae is often unsatisfactory. To obtain more satisfactory results, we have relied upon a correlative approach encompassing a variety EM techniques, i.e., scanning for topographical features and cryotomy, negative staining and thin sectioning to provide a more complete structural characterization of B. burgdorferi.For characterization, isolates of B. burgdorferi were cultured in BSK II media from which they were removed by low speed centrifugation. The sedimented borrelia were carefully resuspended in stabilizing buffer so as to preserve their features for scanning and negative staining. Alternatively, others were prepared for conventional thin sectioning and for cryotomy using modified procedures. For thin sectioning, the fixative described by Ito, et al.

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