Results 111 to 120 of about 476,683 (323)

Deriving the Ionospheric Electric Field From the Bulk Motion of Radar Aurora in the E‐Region

Journal of Geophysical Research: Space Physics, Volume 129, Issue 11, November 2024.
Abstract In the auroral E‐region strong electric fields can create an environment characterized by fast plasma drifts. These fields lead to strong Hall currents which trigger small‐scale plasma instabilities that evolve into turbulence. Radio waves transmitted by radars are scattered off of this turbulence, giving rise to the ‘radar aurora’.
Magnus F. Ivarsen, Jean‐Pierre St‐Maurice, Devin R. Huyghebaert, Megan D. Gillies, Frank Lind, Brian Pitzel, Glenn C. Hussey   +6 more
wiley   +1 more source

Residual stress determination by blind hole drilling and local displacement mapping in aluminium alloy aerospace components

Fracture and Structural Integrity
The determination of residual stresses by combining blind hole drilling and optical interferometric measurement of relief deformation is re-visited to evaluate its applicability to aerospace structures.
Sviatoslav Eleonsky, Vladimir Pisarev, Eugene Statnik, Alexey Salimon, Alexander Korsunsky   +4 more
doaj   +5 more sources

Monitoring of Ionospheric Variability Using the Low lAtitude Long Range Ionospheric raDar (LARID): Capabilities, Advantages and Limitations

Space Weather, Volume 22, Issue 11, November 2024.
Abstract A Low lAtitude long Range Ionospheric raDar (LARID), which was built recently at Dongfang (19.2°N, 108.8°E, magnetic latitude 13.9°), Hainan Is., China, is employed to study the ionospheric variability over a large region. The LARID consists of two high frequency (HF) coherent backscatter radars, looking toward east and west, respectively ...
Wenjie Sun, Guozhu Li, Baiqi Ning, Lianhuan Hu, Yuichi Otsuka, Guofeng Dai, Haiyong Xie, Xiukuan Zhao, Yi Li, Atsuki Shinbori, Michi Nishioka, Septi Perwitasari, Chi Wang   +12 more
wiley   +1 more source

Optimising collection geometry for long‐range synthetic aperture sonar interferometry

IET Radar, Sonar &Navigation, Volume 18, Issue 11, Page 2034-2043, November 2024.
A technique is presented to optimise data collection geometry in synthetic aperture sonar interferometry. This can be used to maximise the area coverage rate in seabed imaging and mapping. Abstract Interferometric synthetic aperture sonar (SAS) is a technique to image and map the seabed in very high resolution. For large area coverage rate systems with
Roy Edgar Hansen, Torstein Olsmo Sæbø
wiley   +1 more source

A parametric study of laser spot size and coverage on the laser shock peening induced residual stress in thin aluminium samples

The Journal of Engineering, 2015
Laser Shock Peening is a fatigue enhancement treatment using laser energy to induce compressive Residual Stresses (RS) in the outer layers of metallic components.
M. Sticchi, P. Staron, Y. Sano, M. Meixer, M. Klaus, J. Rebelo-Kornmeier, N. Huber, N. Kashaev   +7 more
doaj   +1 more source

The theory of intensity interferometry revisited [PDF]

arXiv, 2020
With the current revival of interest in astronomical intensity interferometry, it is interesting to revisit the associated theory, which was developed in the 1950s and 1960s. This paper argues that intensity interferometry can be understood as an extension of Fraunhofer diffraction to incoherent light. Interference patterns are still produced, but they
arxiv  

Damage accumulation near the cold-expanded hole due to high-cycle fatigue by crack compliance method

Fracture and Structural Integrity, 2021
The novel destructive method is implemented for quantitative assessment of fatigue damage accumulation in the stress concentration zone accompanied by residual stress due to cold expansion of the through-thickness hole. Damage accumulation is reached by
Sviatoslav Eleonsky, Yuri Matvienko , Vladimir Pisarev, Michael Zajtsev   +3 more
doaj  

Dynamic Sensing Performance of a Point-Wise Fiber Bragg Grating Displacement Measurement System Integrated in an Active Structural Control System

Sensors, 2011
In this work, a fiber Bragg grating (FBG) sensing system which can measure the transient response of out-of-plane point-wise displacement responses is set up on a smart cantilever beam and the feasibility of its use as a feedback sensor in an active ...
Chien-Ching Ma, Heng-Tseng Liao, Kuo-Chih Chuang   +2 more
doaj   +1 more source

Stellar intensity interferometry over kilometer baselines: Laboratory simulation of observations with the Cherenkov Telescope Array

, 2014
A long-held astronomical vision is to realize diffraction-limited optical aperture synthesis over kilometer baselines. This will enable imaging of stellar surfaces and their environments, show their evolution over time, and reveal interactions of stellar
Dravins, Dainis, Lagadec, Tiphaine
core   +1 more source

Optical strain measuring techniques for high temperature tensile testing [PDF]

A number of optical techniques used for the analysis of in-plane displacements or strains are reviewed. The application would be for the high temperature, approximately 1430 C (2600 F), tensile testing of ceramic composites in an oxidizing atmosphere ...
Gyekenyesi, John Z., Hemann, John H.
core   +1 more source