Results 61 to 70 of about 11,470 (155)

Nonlinear vibration analysis of a rotor supported by magnetic bearings using homotopy perturbation method

Propulsion and Power Research, 2017
In this paper, the effects of nonlinear forces due to the electromagnetic field of bearing and the unbalancing force on nonlinear vibration behavior of a rotor is investigated.
Aboozar Heydari, Mina Mirparizi, Farshad Shakeriaski, Farhad Sheykh Samani, Mohamadreza Keshavarzi   +4 more
doaj   +1 more source

Polar motion excited by atmosphere and ocean in multi-frequency bands

Geo-spatial Information Science, 2010
This research aims to study the influences of the atmospheric and oceanic excitations on polar motion. Power spectrum density analyses show that the efficiencies of the atmospheric and oceanic excitations differ not only at different frequencies but also in the retrograde and prograde components, but the sum of atmospheric and oceanic excitations shows
Wei Chen, Wenbin Shen
openaire   +1 more source

Short periodic variations of polar motion and hemispheric atmospheric angular momentum excitation functions in the period 1984-1992

Annales Geophysicae
Short periodic oscillations with the periods from 10 up to 110 days of the hemispheric components of effective atmospheric angular momentum (EAAM) excitation function and their correlation with polar motion excitation function have been analyzed.
J. Nastula
doaj  

COLLECTIVE EXCITATIONS IN ALPHA-HELICAL PROTEIN MOLECULE

Российский технологический журнал, 2018
Continuous energy supply, a necessary condition for life, excites a state far from thermodynamic equilibrium, in particular coherent electric polar vibrations depending on water ordering in the cell.
V. N. Kadantsev, A. N. Goltsov
doaj   +1 more source

Analysis of combined series of hydrological angular momentum developed based on climate models

Frontiers in Earth Science
Mass changes in the hydrosphere represent an important contributor to polar motion (PM) variations, especially at seasonal time scales (i.e., annual and semiannual).
Jolanta Nastula, Justyna Śliwińska-Bronowicz, Małgorzata Wińska, Tomasz Kur   +3 more
doaj   +1 more source

Analytical models and amplification effects of seismic wave propagation in canyon sites

Yantu gongcheng xuebao, 2019
Morphologically, there are three types of topographic and site conditions in nature: flat, convex and concave sites. The canyon (or valley) is a common concave site, and a large number of structures such as earth-rock dams and bridges have been built in ...
GAO Yu-feng
doaj   +1 more source

Can we explain the post-2015 absence of the Chandler wobble?

Earth, Planets and Space
Recent polar motion data do not show a 6-year beat and indicate the absence of the Chandler wobble (CW), whereas we could observe the 6-year beat even in the 1920-40 s when the CW amplitude was known to be smallest.
Ryuji Yamaguchi, Masato Furuya
doaj   +1 more source

Evidence for excitation of polar motion by fortnightly ocean tides

Geophysical Research Letters, 1996
The second‐degree zonal tide raising potential, which is responsible for tidal changes in the Earth's rotation rate and length‐of‐day, is symmetric about the polar axis and hence can excite the Earth's polar motion only through its action upon nonaxisymmetric features of the Earth such as the oceans.
Richard S. Gross, Kamal H. Hamdan, Dale H. Boggs   +2 more
openaire   +1 more source

Improved polar motion prediction with denoised geophysical fluid excitation information and long short term memory neural network

Earth, Planets and Space
Polar Motion (PM) is a crucial parameter linking the celestial and terrestrial reference frames. Integrating Earth's fluid effective angular momentum (EAM) and neural network is an effective way to improve PM prediction accuracy.
Qiaoli Kong, Guoli Bo, Xishun Li, Jingwei Han, Lulu Zhang, Yuanwei Wu, Puxuan Wu, Xiyuan Jing, Xuhai Yang, Haihua Qiao   +9 more
doaj   +1 more source

High-precision earth rotation parameter forecasting: multiscale computational models and multivariate data fusion

International Journal of Digital Earth
Earth Rotation Parameters (ERPs, including polar motion and length-of-day in this study) serve as the essential link of celestial-terrestrial reference frames.
Kunpeng Shi, Hao Ding, Xiaodong Chen, Xizhi Hu, Weiping Jiang, Heping Sun   +5 more
doaj   +1 more source