Results 251 to 260 of about 254,167 (296)
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Trunk muscle activities during asymmetric twisting motions
Journal of Electromyography and Kinesiology, 1998Axial twisting of the torso has been identified via epidemiologic studies as a significant risk factor for occupationally-related low back disorders. However, only recently have biomechanical studies been able to describe how twisting is accomplished through the use of the trunk musculature.
W S, Marras, K G, Davis, K P, Granata
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Topological activity in Bragg elliptical twisted fibers
Applied Optics, 2012We have theoretically shown that Bragg twisted elliptical fibers manifest, in certain spectral regions, the property of topological activity--the ability to change in the reflected field the topological charge of incoming optical vortices and fundamental modes by two units.
Constantine N, Alexeyev +3 more
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Chemical & Engineering News Archive, 2011
THE AMIDE BOND can be activated for cleavage under mild, neutral conditions by chemical derivatization, a British group has demonstrated ( Angew. Chem. Int. Ed., DOI: 10.1002/anie.201107117). Amide bonds are notoriously tough to break. Under mild, neutral-pH conditions, reaction times for bond cleavage are more than 100 years.
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THE AMIDE BOND can be activated for cleavage under mild, neutral conditions by chemical derivatization, a British group has demonstrated ( Angew. Chem. Int. Ed., DOI: 10.1002/anie.201107117). Amide bonds are notoriously tough to break. Under mild, neutral-pH conditions, reaction times for bond cleavage are more than 100 years.
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An Australian Feminist Twist on Transnational Labor Activism
Signs: Journal of Women in Culture and Society, 2008Refereed/Peer ...
Suzanne Franzway, Mary Margaret Fonow
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Twist of magnetic fields in solar active regions
Journal of Astrophysics and Astronomy, 2000Extended abstractIn the solar atmosphere, the magnetic and current helicity have played an important role in the study of twisted magnetic field. Current helicity parameterh∥=B∥· (∇ ×B)∥and force free factorcan be used to analyze the distribution of twisted field (current helicity) in the photosphere (Seehafer 1990; Pevtsovet al.1995; Bao & ...
Hongqi Zhang +3 more
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Tunable Optical Activity in Twisted Anisotropic Two-Dimensional Materials
ACS Nano, 2023Twisted van der Waals structures exhibit a variety of unusual electrical and optical phenomena and could provide a powerful means for designing nanodevices with tunable chiral properties. However, programming intrinsic chiral properties of the film on the atomic scale remains a great challenge due to the limitations of fabrication and measurement ...
Su-Yun Wang +5 more
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Dynamic Stall Alleviation Using Active Twist
2015In the previous chapters, moderate speed regimes of the helicopter have been explored, where flow separation and stall is not so important. However, it is possible that substantial flow separation on the rotor may cause very high levels of vibrations which active twist may not be able to reduce.
Ranjan Ganguli +2 more
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Dynamic response of active twist rotor blades
41st Structures, Structural Dynamics, and Materials Conference and Exhibit, 2000Dynamic characteristics of active twist rotor (ATR) blades are investigated analytically and experimentally in this paper. The ATR system is intended for vibration and potentially for noise reductions in helicopters through individual blade control. An aeroelastic model is developed to identify frequency response characteristics of the ATR blade with ...
Carlos E S Cesnik +2 more
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The Aerodynamics of an Actively Twisted Wing
Aerospace, 2005Aerodynamic performance of aircraft can be changed by moving separate surfaces which are mechanically connected to the main wing and moved with complex linkages. A possible alternative method of changing performance with less mechanical complexity is presented.
James R. Sonnenmeier +3 more
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A Review of Active Blade Twist Technology: Part II – Integral Twist Actuation
International Journal of Unmanned Systems Engineering, 2014Marques P. (2014). A review of active blade twist technology: Part II – Integral twist actuation. International Journal of Unmanned Systems Engineering. 2(S2): 26-36. This paper evaluates integral actuation concepts and rotor optimisation for the design of advanced rotor-UAVs (RUAVs). Design and optimization of adaptive helicopter rotor blades requires
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