Results 81 to 90 of about 75,702 (263)

Helicopter low-speed yaw control [PDF]

open access: yes, 1993
A system for improving yaw control at low speeds consists of one strake placed on the upper portion of the fuselage facing the retreating rotor blade and another strake placed on the lower portion of the fuselage facing the advancing rotor blade.
Crowell, Cynthia A.   +2 more
core   +1 more source

Resource reallocation across successive systemic innovations: How Rolls‐Royce shaped the evolution of the turbojet, turboprop, and turbofan

open access: yesStrategic Management Journal, EarlyView.
Abstract Research Summary Despite the importance of resource reallocation in shaping a variety of strategic outcomes, strategy scholars have paid only limited attention to the processes by which firms reallocate their resources across successive systemic innovations.
Gino Cattani   +2 more
wiley   +1 more source

Vibrational Exfoliation of 2D Materials

open access: yesSmall, EarlyView.
Vibrational energy folds, fractures and exfoliates atomically and molecularly thin materials. Combining experimentation and computational methods, this unique vibrational synthesis pathway is revealed. This process overcomes barriers of existing approaches by processing 1000 g/L dispersions without loss in yield.
Aadam Rabani   +5 more
wiley   +1 more source

Control load envelope shaping by live twist [PDF]

open access: yes
Rotor control systems experience a rapid load growth resulting from retreating blade stall during flight conditions of high blade loading or airspeeds.
Mirick, P. H., Tarzanin, F. J., Jr.
core   +1 more source

Unsteady loads for coaxial rotors in forward flight computed using a vortex particle method [PDF]

open access: yes, 2018
Recent advances in coaxial rotor design have shown benefits of this configuration. Nevertheless, issues related to rotor-head drag, aerodynamic performance, wake interference, and vibration should also be considered.
Barakos, George   +2 more
core   +1 more source

Efficient Harvesting of Irregular and Low‐Frequency Mechanical Energy via Hybridized Electromagnetic‐Triboelectric Systems

open access: yesSmall, EarlyView.
ABSTRACT The rapid expansion of the Internet of Things (IoT) and wearable electronics necessitates sustainable power sources to replace the limited electrochemical battery. While mechanical energy harvesting offers a promising solution, traditional harvesters face challenges of irregular and low−frequency environmental sources. This review presents the
Yongbin Han   +2 more
wiley   +1 more source

An experimental investigation of the flap-lag stability of a hingeless rotor with comparable levels of hub and blade stiffness in hovering flight [PDF]

open access: yes
An experimental investigation of the flap-lag stability of a hingeless rotor in hovering flight is presented and discussed. The rotor blade and hub configuration were selected such that the hub and blade had comparable levels of bending stiffness ...
Curtiss, H. C., Jr., Putman, W. F.
core   +1 more source

Predicting the wake structure of the HART II rotor using the vorticity transport model [PDF]

open access: yes, 2008
Brown’s Vorticity Transport Model has been used to predict the wake structure and resultant blade loading of the rotor that was studied during the HART II experimental programme. The descending flight condition of the experiment yields significant high-
Brown, R.E., Kelly, M.E.
core   +1 more source

EE2 and the Fish Brain: Age‐Dependent Impact of 17α‐Ethinylestradiol on Brain Cell Proliferation and Behavior in Sea Bass Larvae

open access: yesEnvironmental Toxicology, EarlyView.
ABSTRACT Endocrine‐disrupting chemicals (EDCs), such as 17α‐ethinylestradiol (EE2), have raised concerns about their potential effects on aquatic organisms, particularly during early developmental stages. In this context, the study of behavioral disruption has gained considerable attention, as it may have consequences on individual fitness and ...
Soloperto Sofia   +6 more
wiley   +1 more source

Technical Damage in Wind Rotor Blade under Static Load at Environment Conditions

open access: yesChemical Engineering Transactions, 2014
Accidents with a wind rotor blade are frequently observed in the wind farms and the simulation study of its undesired damage and its full degradation has to be done. As usual the full degradation of the wind rotor blade happens in a sequence of appearing
W. Becker   +3 more
doaj   +1 more source

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