Results 101 to 110 of about 94,319 (292)
AerospaceThe rotor–stator interaction noise is a major source of fan noise. Especially for low-speed fan stages, the tonal component is typically a dominant noise source.
Stephen Schade +3 more
doaj +1 more source
Results of the noise measurement program on a standard and modified OH-6A helicopter [PDF]
A field noise measurement program has been conducted on a standard OH-6A helicopter and one that had been modified by reducing the rotor speed, altering rotor tip shape, and treating the engine exhaust and inlet to reduce the external noise levels.
Henderson, H. R. +2 more
core +1 more source
International Journal of Robust and Nonlinear Control, EarlyView.ABSTRACT This paper addresses the problem of dynamic output‐feedback H∞$$ {H}_{\infty } $$ detector‐based control for continuous‐time Markov Jump Lur'e Systems with uncertain transition rate matrices. In contrast to conventional approaches, the proposed synthesis conditions are derived using Finsler's lemma, introducing additional slack variables to ...
Lucas P. M. Silva +2 more
wiley +1 more source
Blade planform for a quiet helicopter [PDF]
The effects of blade planform and tip speed on noise and performance for a Hughes 500 C rotor system were studied. A cursory examination of the effects of such planform shapes as regular, inverse, and no taper on the noise and performance of the rotor ...
Ram, D. S. J.
core +1 more source
The Evolution of Autonomous Systems for Planetary Cave Exploration: A Review
Journal of Field Robotics, EarlyView.ABSTRACT The exploration of Subsurface Access Points (SAPs), such as lava tubes on the Moon and Mars, has gained significant interest due to their potential as stable environments shielded from surface radiation and temperature extremes. These sites are considered high‐value targets for detecting water and signs of ancient life, and assessing their ...
Sarah Swinton +4 more
wiley +1 more source
A Quiet Helicopter for Air Taxi Operations [PDF]
NASA is exploring rotorcraft designs for VTOL air taxi operations, also known as urban air mobility (UAM) or on-demand mobility (ODM) applications. Several concept vehicles have been developed, intended to focus and guide NASA research activities in ...
Johnson, Wayne
core +1 more source
Accounting for animal movement during aerial imaging surveys
Remote Sensing in Ecology and Conservation, EarlyView.Animals are not stationary during aerial surveys; if their movements are related to the movement of the aerial platform, then bias can be introduced into subsequent population count estimates. We sought to establish a framework for assessing the impacts of animal movement on count error and platform bias by comparing aggregated counts and relative ...
Rowan L. Converse +5 more
wiley +1 more source
Ain Shams Engineering JournalTwo Switched Reluctance Motors (SRMs) rated to 3 kW and 6 kW have been designed for L5M and L5N (High-speed passenger and cargo) electric three-wheeler traction application.
Arjun Seshadri +2 more
doaj +1 more source
Evaluation of the annoyance due to helicopter rotor noise [PDF]
A program was conducted in which 25 test subjects adjusted the levels of various helicopter rotor spectra until the combination of the harmonic noise and a broadband background noise was judged equally annoying as a higher level of the same broadband ...
Doyle, L. B., Sternfeld, H., Jr.
core +1 more source
Non-monotonic diffusion rates in atom-optics L\'{e}vy kicked rotor
, 2019 The dynamics of chaotic Hamiltonian systems such as the kicked rotor continues to guide our understanding of transport and localization processes.
Mangaonkar, Jay +5 more
core +1 more source