Results 31 to 40 of about 21,200 (250)

Variable-speed tail rotors for helicopters with variable-speed main rotors [PDF]

The Aeronautical Journal, 2017
ABSTRACTVariable tail rotor speed is investigated as a method for reducing tail rotor power, and improving helicopter performance. A helicopter model able to predict the main rotor and tail rotor powers is presented, and the flight test data of the UH-60A helicopter is used for validation. The predictions of the main and tail rotor powers are generally
Han, D., Barakos, G.N.
openaire   +1 more source

Electroactive 3D Porous Graphene Foam Impedimetric Biosensor for Ultrasensitive Detection of MCF‐7‐Cells‐Derived Extracellular Vesicles in Human Serum

Advanced Materials Technologies, EarlyView.
A label‐free impedimetric biosensor based on electroactive 3D porous graphene foam enables ultrasensitive and selective detection of CD81 protein and MCF‐7 cell‐derived extracellular vesicles in human serum. Detection limits of 0.048 fg/mL for CD81 and ∼24 EVs/mL are achieved, demonstrating a robust platform for selective, label‐free, and ...
Michael Robert Furness, Ashish Kalkal, Tia Wardlaw, Jessica Valli, Suresh Chandra Baral, Pablo Lozano Sanchez, Marco Caffio, Sudhagar Pitchaimuthu, Olga Oikonomidou, Jason Webber, Nick R. Leslie, Anitha Devadoss   +11 more
wiley   +1 more source

Research of the crosswind effect on the single-rotor helicopter unintentional yaw rotation

Научный вестник МГТУ ГА
During the operation of single-rotor helicopters, aviation accidents quite frequently occur in the form of an unintentional turn or even a yaw rotation, causing, as a rule, a ground collision.
V. V. Efimov, V. A. Ivchin, K. O. Chernigin   +2 more
doaj   +1 more source

A New Algorithm on Automatic Trimming for Helicopter Rotor Aerodynamic Loads

Aerospace, 2023
In order to simulate the flight state of the helicopter effectively, it is necessary to trim the helicopter during the forward flight in a wind tunnel test.
Xinfan Yin, Hongxu Ma, Xianmin Peng, Guichuan Zhang, Honglei An, Liangquan Wang   +5 more
doaj   +1 more source

Collision‐Resilient Winged Drones Enabled by Tensegrity Structures

Advanced Robotics Research, EarlyView.
Based on structures of birds such as the woodpeck, this article presents the collision‐resilient aerial robot, SWIFT. SWIFT leverages tensegrity structures in the fuselage and wings which allow it to undergo large deformations in a crash, without sustaining damage. Experiments show that SWIFT can reduce impact forces by 70% over conventional structures.
Omar Aloui, Raphael Zufferey, William Stewart, Mohammad Askari, Simon Jeger, Dario Floreano   +5 more
wiley   +1 more source

Nonlocomotory Robotic Strategies for Dynamic Rotation Control in Terrestrial Robots: A Review

Advanced Robotics Research, EarlyView.
Terrestrial robots increasingly require rapid body rotation to maintain stability and agility in complex environments. This review shows nonlocomotory rotational control strategies that operate without ground contact, including reaction wheels, tails, bars, limbs, and thrusters.
Y. Liang, J. An, X. Zheng, D. Wang, S. Wang, X. Wang, P. Zhu, J. Pei, S. Li, J. Paripurana, Y. Han, Z. Tang, X. Gan, Q. He, X. Ma   +14 more
wiley   +1 more source

Short Sb···Sb Contacts in Polymorphic Tris(p‐Tolyl)Antimony: A Hallmark of Organoantimony(III) Solid‐State Chemistry?

Angewandte Chemie, EarlyView.
Discovery of polymorphism in solid tris(p‐tolyl)antimony(III) highlighted short, direct antimony‐antimony contacts, with interatomic separation shorter than the sum of the van der Waals radii, and calculated interaction energy of ca. 26 kJ mol−1 that includes a significant dispersion component.
Imogen Suh, Michael Ferguson, Filip Topić, Fu‐Qiang Gong, Mihails Arhangelskis, Hatem M. Titi, D. Scott Bohle, Vinko Nemec, Levente Kiss, Andrew J. Morris, Cristian Silvestru, Dominik Cinčić, Tomislav Friščić   +12 more
wiley   +2 more sources

IL‐7R‐Enriched Extracellular Vesicles From the Thymus Drive Colitis via Promoting Neutrophil Extracellular Trap Formation

Advanced Science, EarlyView.
Inflammatory bowel disease (IBD) pathogenesis remains unclear. This study reveals that thymus‐originated IL‐7R‐enriched extracellular vesicles exacerbate colitis by promoting neutrophil extracellular traps via a thymus‐gut axis, uncovering an inter‐organ communication mechanism in inflammatory bowel disease pathogenesis.
Yao Liao, Yuheng Liu, Ruibing Yang, Zifeng Zhu, Junwei Wu, Dinghao Li, Jin Su, Yingxin He, Shiqi Luo, Feiyang Cao, Haiyi Deng, Lanmengxi Yang, Ling Zhong, Peiying Peng, Xinyi Wu, Chunmei Cai, Zhen Li, Yujin Wu, Shuofeng Zhu, Jie Wei, Yi Yang, Lifu Wang   +21 more
wiley   +1 more source

Failure of a Tail Rotor Blade in a Helicopter [PDF]

, 2005
Abstract A helicopter lost the outboard rib on a tail rotor blade in flight and was forced to land because of the resulting vibrations. The investigation that followed is described in this chapter along with key findings. As shown in a sketch, the rib is held in place by a set of six rivets.
openaire   +2 more sources

Sustainable Fabrication of Tailored Bone Substitutes: From High‐Throughput Scaffold Manufacturing, Scaled‐Up HMSC Expansion to Dynamic Cultivation in a Perfusion Bioreactor

Advanced Science, EarlyView.
ABSTRACT The demand for off‐the‐shelf biocompatible bone substitutes has driven the development of numerous independent in vitro technologies to generate products resembling physiological tissues. Due to technical challenges and overly simplified cultivation approaches/niches, the end‐products are often uniformly shaped and inferior to native bone ...
Franziska Braun, Anna Paříková, Sandra Rother, Martin Kantor, Salman Muhammad Ilyas, Ricardo Bernhardt, Pavel Ndjawa Yomi, Jaromír Havlica, Revathi Appali, Benjamin Kruppke, Poh Soo Lee   +10 more
wiley   +1 more source