Article
Astronomy & Astrophysics
Supakchai Ponglertsakul, Piyabut Burikham, Sitthichai Pinkanjanarod
Summary: The quadrupole normal mode oscillation frequency fn of multiquark stars is calculated for n = 1-5. The transition from low to high density multiquark in the core region results in a jump in the first two modes, indicating the presence of a high-density core. When the star's oscillation couples with spacetime, gravitational waves (GW) are generated and the star undergoes damped oscillation. The computation of quasinormal modes (QNMs) using two methods, direct scan and WKB, reveals small imaginary QNMs with frequencies of 1.5-2.6 kHz and damping times of 0.19-1.7 secs, as well as large imaginary QNMs with frequencies of 5.98-9.81 kHz and damping times of 0.13-0.46 ms.
Article
Automation & Control Systems
Cheng Qian, Jiajun Xu, Changchun Hua, Kyoung-Su Park
Summary: This article establishes a mathematical model for mechanical-electrical-hydraulic vertical torsional coupling vibration and investigates a vibration suppression control strategy with time varying full state constraints. By utilizing dynamic theory, nonlinear constraint transformation functions, and neural networks, a vibration suppression control algorithm is designed and its effectiveness is verified through simulation.
INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL
(2022)
Article
Astronomy & Astrophysics
Eleonora Di Valentino, Stefano Gariazzo, Olga Mena
Summary: In this study, robust and model-marginalized limits on the total neutrino mass and abundances were presented using cosmological observations. The results showed a preference for the degenerate neutrino mass spectrum over the normal and inverted hierarchy possibilities. The ACDM minimal scenario was strongly favored over possible extensions. The most constraining bound on the total neutrino mass was found to be sigma m(1) < 0.087 eV in the ACDM + sigma m(1) model, and the parameter N-eff was restricted to 3.08 +/- 0.17 in the ACDM + Neff model. These limits remained almost unchanged when considering the ACDM + sigma m(1) + Neff scenario.
Article
Geochemistry & Geophysics
Hao Liu, Michael Gurnis, Wei Leng
Summary: The study indicates that the presence of a low viscosity channel (LVC) in the mantle will reduce the amplitude of long wavelength geoid highs over slabs, while affecting the dip angle and tension distribution of slabs. A viscosity increase at 660 km depth leads to strong downdip compression within slabs, a pattern that largely disappears with the introduction of the LVC.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2021)
Article
Mechanics
Yadan Mao
Summary: The size of the insulating plate is crucial in determining plate motion and flow-structure interaction. With increasing plate size, the thermal blanket effect becomes stronger, allowing the plate to transition from periods of stagnancy to unidirectional movement. The speed of plate motion is proportional to the average plume distance and open surface area, with longer-wavelength structures dominating at higher plate speeds.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Geochemistry & Geophysics
E. Kendall, A. M. G. Ferreira, S. J. Chang, M. Witek, D. Peter
Summary: In this study, constraints on the radially anisotropic upper mantle structure beneath the Pacific were provided through waveform modeling and inversion. The data show asymmetry at the East Pacific Rise, suggesting that anisotropy in the region is due to shear-driven asthenospheric flow beneath the South Pacific Superswell. Additionally, distinct positive linear anomalies at around 100 km depth in the Pacific may be related to mantle entrainment at subduction zones, flow at the East Pacific Rise, and shape-preferred orientation of melt beneath Hawaii.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2021)
Article
Materials Science, Multidisciplinary
Lu Dai, Jia You, Wenzhong Shen, Ka-Di Zhu, Xiaojiang Huang
Summary: A comprehensive theory has been constructed in this paper to quantitatively analyze the electromechanical properties of close packed and non-close packed electrically conductive helices. The study reveals that the close packed helices are suitable for rotational inversion and axial contraction, while the non-close packed helices are better for larger torsional stroke. This study provides a reliable theoretical reference for further experimental research on the applications of conductive helices in micro-/nanoelectromechanical systems.
MATERIALS & DESIGN
(2023)
Article
Geochemistry & Geophysics
Shiqi Wang, Simon L. Klemperer
Summary: The method distinguishes upper-mantle earthquakes from crustal earthquakes based on the amplitude ratio of seismic waves Sn and Lg ('Sn/Lg'), showing potential for expanding the global catalog of continental earthquakes.
EARTH AND PLANETARY SCIENCE LETTERS
(2021)
Article
Geochemistry & Geophysics
Stuart Russell, Jessica C. E. Irving, Sanne Cottaar
Summary: The core-mantle boundary (CMB) is a complex and poorly understood region of the Earth. Recent research using high frequency synthetic seismograms has found that PKKP diffracted waves are crucial for studying the CMB and can resolve very thin melt layers. Despite evidence suggesting the presence of a global layer of melt at the CMB, it remains inconclusive to either exclude or observe such melt within the available observational data.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)
Article
Geosciences, Multidisciplinary
Sinan Ozaydin, Kate Selway, William L. Griffin
Summary: The study shows that water content decreases with depth in the southwestern Kaapvaal Craton, broadly matching the distribution of metasomatism. While most water content measurements from xenolith samples agree with the models, discrepancies suggest a local metasomatic control over xenolith water contents.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Geosciences, Multidisciplinary
Frederic Deschamps, Laura Cobden
Summary: The translation introduces a new method to estimate the temperature at Earth's core-mantle boundary using seismic measurements, specifically V(S) and Q(S), which provide constraints on the CMB temperature.
FRONTIERS IN EARTH SCIENCE
(2022)
Article
Astronomy & Astrophysics
K. Mandal, S. M. Hanasoge, L. Gizon
Summary: This study successfully extends the methodology to measure even azimuthal orders of Rossby waves in the Sun, adding credibility to the mode-coupling methodology in helioseismology. The results indicate significant power close to the theoretical dispersion relation for sectoral Rossby modes, with maximum power occurring at mode t = 8.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Engineering, Electrical & Electronic
Mai Banawan, Lixian Wang, Sophie LaRochelle, Leslie A. Rusch
Summary: This study investigates the coupling of OAM modes in ring-core fibers due to elliptical shape deformation, introducing a coupling model that shows improved predictions compared to classical modeling approaches. The model captures the disparate behaviors of coupling in lower and higher order degenerate OAM modes, and predicts the OAM order at which orthogonality is maintained despite elliptical deformation. The study also reveals different performance and signal processing requirements for thin and thick RCFs under the same level of elliptical deformation.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2021)
Article
Geochemistry & Geophysics
Sheng-Peng Wang, Zhong-Yuan Ren, Alexander R. L. Nichols, Tserendash Narantsetseg, Qing-Lin Zhang, Le Zhang, Chao Yuan
Summary: The Cenozoic basalts in eastern China are believed to be related to the mantle wedge beneath East Asia. However, the basalts in central and eastern Mongolia, which have similar characteristics, are located far from this mantle system. By analyzing the compositions of basalts, olivines, spinels, and olivine-hosted melt inclusions from Mongolia, researchers found high temperatures and thermal anomalies in the mantle sources feeding the volcanism. They propose a branched plume model to explain the similarity of geochemistry and eruption ages for basalts on both sides of the Daxinganlin-Taihangshan gravity lineament (DTGL).
Article
Physics, Fluids & Plasmas
Ivan Kriuchevskyi, Timothy W. Sirk, Alessio Zaccone
Summary: In this study, a mathematical description of amorphous solid deformation and plasticity is presented by extending the concept of instantaneous normal modes (INMs) to deformed systems. The linear response theory is formulated by considering the strain-dependent tangent modulus, and the prediction shows good agreement with simulations.
Article
Geochemistry & Geophysics
Jon Mound, Chris Davies, Luis Silva
EARTH AND PLANETARY SCIENCE LETTERS
(2015)
Article
Geochemistry & Geophysics
G. A. Cox, P. W. Livermore, J. E. Mound
PHYSICS OF THE EARTH AND PLANETARY INTERIORS
(2016)
Article
Geochemistry & Geophysics
M. C. Metman, P. W. Livermore, J. E. Mound
PHYSICS OF THE EARTH AND PLANETARY INTERIORS
(2018)
Article
Geochemistry & Geophysics
Maurits C. Metman, Philip W. Livermore, Jonathan E. Mound, Ciaran D. Beggan
GEOPHYSICAL JOURNAL INTERNATIONAL
(2019)
Article
Geochemistry & Geophysics
Christopher J. Davies, Jon E. Mound
GEOPHYSICAL JOURNAL INTERNATIONAL
(2019)
Article
Geosciences, Multidisciplinary
Jon Mound, Chris Davies, Sebastian Rost, Jon Aurnou
Article
Mechanics
R. S. Long, J. E. Mound, C. J. Davies, S. M. Tobias
JOURNAL OF FLUID MECHANICS
(2020)
Article
Geosciences, Multidisciplinary
Jonathan E. Mound, Christopher J. Davies
GEOPHYSICAL RESEARCH LETTERS
(2020)
Article
Geosciences, Multidisciplinary
Maurits C. Metman, Ciaran D. Beggan, Philip W. Livermore, Jonathan E. Mound
EARTH PLANETS AND SPACE
(2020)
Article
Geosciences, Multidisciplinary
P. Alken, E. Thebault, C. D. Beggan, H. Amit, J. Aubert, J. Baerenzung, T. N. Bondar, W. J. Brown, S. Califf, A. Chambodut, A. Chulliat, G. A. Cox, C. C. Finlay, A. Fournier, N. Gillet, A. Grayver, M. D. Hammer, M. Holschneider, L. Huder, G. Hulot, T. Jager, C. Kloss, M. Korte, W. Kuang, A. Kuvshinov, B. Langlais, J. -M. Leger, V. Lesur, P. W. Livermore, F. J. Lowes, S. Macmillan, W. Magnes, M. Mandea, S. Marsal, J. Matzka, M. C. Metman, T. Minami, A. Morschhauser, J. E. Mound, M. Nair, S. Nakano, N. Olsen, F. J. Pavon-Carrasco, V. G. Petrov, G. Ropp, M. Rother, T. J. Sabaka, S. Sanchez, D. Saturnino, N. R. Schnepf, X. Shen, C. Stolle, A. Tangborn, L. Toffner-Clausen, H. Toh, J. M. Torta, J. Varner, F. Vervelidou, P. Vigneron, I. Wardinski, J. Wicht, A. Woods, Y. Yang, Z. Zeren, B. Zhou
Summary: The IAGA V-MOD working group adopted the thirteenth generation of the IGRF in December 2019, which includes definitive main field models for epoch 2015.0 and 2020.0, as well as predictive linear secular variations for 2020.0 to 2025.0. This update provides equations, spherical harmonic coefficients, and maps for magnetic parameters and their predicted changes from 2020.0 to 2025.0.
EARTH PLANETS AND SPACE
(2021)
Article
Multidisciplinary Sciences
Fei He, Yong Wei, Stefano Maffei, Philip W. Livermore, Christopher J. Davies, Jon Mound, Kaihua Xu, Shuhui Cai, Rixiang Zhu
Summary: Localized regions of low geomagnetic intensity, such as the South Atlantic Anomaly, allow energetic particles from the Van Allen radiation belt to precipitate into the atmosphere, resulting in a red aurora-like airglow visible to the naked eye. Research suggests that the West Pacific Anomaly experienced low geomagnetic intensity during the sixteenth to nineteenth centuries, with complex fluctuations in auroral frequency associated with time-dependent upwelling flows in the Earth's core, potentially driven by regional lower-mantle anomalies. This behavior has been masked by the smoothing effects of regularized global geomagnetic models.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Geochemistry & Geophysics
M. Murphy Quinlan, A. M. Walker, C. J. Davies, J. E. Mound, T. Muller, J. Harvey
Summary: Modeling the planetary heat transport of small bodies in the early Solar System is key to understand the geological context of meteorite samples. Including temperature-dependence in the models is crucial for accurate interpretations of the origin of different classes of meteorites. The thermal properties of parent bodies play a significant role in the timing and depth of meteorite genesis.
JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS
(2021)
Article
Geochemistry & Geophysics
Sam Greenwood, Christopher J. Davies, Jon E. Mound
Summary: This study focuses on the thermal origin of the stable layer at the top of Earth's outer core and conducts a systematic investigation into the core's thermal evolution. The findings show that many scenarios for the history of CMB heat flow leading to thermal stratification are inconsistent with exponential trends from mantle evolution models.
PHYSICS OF THE EARTH AND PLANETARY INTERIORS
(2021)
Article
Physics, Fluids & Plasmas
Robert S. Long, Jon E. Mound, Christopher J. Davies, Steven M. Tobias
PHYSICAL REVIEW FLUIDS
(2020)
Article
Mechanics
Jon E. Mound, Christopher J. Davies
JOURNAL OF FLUID MECHANICS
(2017)