Article
Mechanics
Jenny Dingwall, Tomas Chor, John R. Taylor
Summary: Buoyant materials such as microplastics accumulate near the ocean surface in regions with convergent surface currents, posing a threat to marine life. Through large eddy simulations, we study the transport and accumulation of buoyant materials in a turbulent ocean mixed layer under wind and convection forcing. We observe the formation of persistent convective vortices that trap buoyant particles due to surface cooling and find a bias towards cyclonic vorticity. The presence of wind forces leads to a transition from convective cells to longitudinal wind rolls, affecting the trapping and clustering of buoyant materials.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Environmental Sciences
Shenjie Zhou, Andrew J. S. Meijers, Michael P. P. Meredith, E. Povl Abrahamsen, Paul R. R. Holland, Alessandro Silvano, Jean-Baptiste Sallee, Svein Osterhus
Summary: As climate change alters sea-ice formation and circulation patterns, there has been a reduction in dense-water formation around Antarctica. The Weddell Sea has experienced over 40% reduction in dense-water formation since 1992, which could impact global overturning circulation. This study highlights the importance of Antarctic Bottom Water for oceanic heat and carbon sequestration, and the observed decrease in Weddell Sea Bottom Water volume since 1992.
NATURE CLIMATE CHANGE
(2023)
Article
Multidisciplinary Sciences
Luke M. M. Kearney, Christopher W. W. MacMinn, Richard F. F. Katz, Chris Kirkham, Joe Cartwright
Summary: This paper investigates the influence of compression and pressure diffusion on pressure release events, finding that pressure diffusion can significantly shorten the venting period, and plays an important role in fluid expulsion in mudstone-dominated basins.
PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2023)
Article
Chemistry, Physical
Yunzhong Wang, Anh Tran Tam Pham, Xiangxi Han, Dongsheng Du, Youhong Tang
Summary: Wave energy is utilized as an alternative renewable energy source through the use of a wave-driven TENG prototype that has been optimized for performance under different ocean conditions. The preliminary results show promising output voltage and sustainable charging capabilities, as well as durability and adaptability under various frequencies and amplitudes of ocean waves.
Article
Multidisciplinary Sciences
S. S. Tanikella, M. C. Sigallon, E. Dressaire
Summary: During hydraulic fracturing, fluid-filled fractures are formed and grow when pressurized fluid is injected into a brittle elastic medium. In our experimental study on fracture dynamics, we investigate the behavior of fractures propagating in the viscous regime. We measure the fracture aperture and radius over time for different mechanical properties of the medium and fluid, as well as injection parameters. Our results show that the fracture continuously expands even after injection stops and follows scaling arguments that predict the radius scaling as t(1/9). These findings provide insights into hydraulic fracture propagation in rocks.
PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2023)
Review
Environmental Sciences
Andrei Bagaev, Elena Esiukova, Daria Litvinyuk, Irina Chubarenko, Subramanian Veerasingam, Ramadoss Venkatachalapathy, Liudmila Verzhevskaya
Summary: Russia has 12 seas, with plastic contamination confirmed in 7 of them, showing significant variations in pollution levels. Research projects on plastic contamination use their own collection and extraction methods, leading to difficulties in comparing results and inconsistencies in sampling methodology and identification techniques.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2021)
Article
Meteorology & Atmospheric Sciences
Lavinia Patara, Claus W. Boening, Toste Tanhua
Summary: Enhanced Southern Ocean ventilation in recent decades is suggested as a relevant modulator of ocean heat and carbon uptake changes. This study focuses on midlatitude ventilation changes in the Southern Ocean from the 1960s to the 2010s, showing a multidecadal fluctuation with a decrease until the 1980s-90s and subsequent increase. Wind stress is identified as the main driver of ventilation changes, while buoyancy forcing modulates its trend and decadal variability.
JOURNAL OF CLIMATE
(2021)
Article
Materials Science, Multidisciplinary
Elisa A. Bergkamp, Clemens V. Verhoosel, Joris J. C. Remmers, David M. J. Smeulders
Summary: This paper presents a model for fluid-driven propagation of discrete fractures in poroelastic continua. The model considers the skin permeability and fluid slip effects at the fracture walls, which are particularly important for subsurface applications. The development of a fracture propagation criterion requires the incorporation of all dissipative mechanisms involved. This work proposes a thermodynamically consistent J-integral formulation for fracture propagation based on the theory of linear elastic fracture mechanics. The proposed poroelastic J-integral formulation is validated using analytical approximations in the stationary setting. The propagation criterion is implemented in an extended finite element method (X-FEM) simulation framework for propagating fractures, providing insights into the role of skin and slip effects on fluid-driven fracture propagation in poroelastic media.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2023)
Article
Water Resources
Xiaoli Liu, Shouming Liu, Hongyi Zhao, Dong-Sheng Jeng, Longtao Guo, Tianyuan Zheng
Summary: This study investigates the interplay between solute transport and wave-induced seepage process in sediments with poor drainage conditions. The results demonstrate that the accumulated seepage flow significantly affects the advective and dispersive fluxes of solute, leading to the migration of solute layer. The parametric study reveals that the thickness of the seabed, relative density, shear modulus, and soil permeability play important roles in the effect of accumulated pore water pressure on solute migration.
ADVANCES IN WATER RESOURCES
(2023)
Article
Geology
Matias Clunes, John Browning, Carlos Marquardt, Jorge Cortez, Kyriaki Drymoni, Janine Kavanagh
Summary: Considering the impact of inclined layers in the crust on ground deformation is crucial for assessing potential volcanic eruptions. Our numerical simulations show that inclined layers can result in localized ground deformation that is up to 40 times higher in magnitude compared to non-layered models. These findings highlight the importance of accurately characterizing the mechanical properties and orientation of the geological layers beneath active volcanoes.
Article
Physics, Multidisciplinary
Carlos Saji, Roberto E. Troncoso, Vagson L. Carvalho-Santos, Dora Altbir, Alvaro S. Nunez
Summary: In this study, the scattering behavior of spin waves by magnetic Hopfions was investigated using a micromagnetic approach. It was found that the spin waves experience an electromagnetic field generated by the Hopfion and are deflected by the magnetic texture. This research is significant for understanding the scattering properties of magnetic Hopfions.
PHYSICAL REVIEW LETTERS
(2023)
Article
Mechanics
Giridar Vishwanathan, Gabriel Juarez
Summary: Oscillatory flows have the potential to overcome limitations of using steady flows for inertial focusing due to low particle Reynolds numbers. Unsteady inertial forces on inertial focusing have not been thoroughly examined. Experimental and theoretical studies show that oscillatory flows are remarkably efficient for inertial focusing, even at low particle Reynolds numbers.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Multidisciplinary Sciences
Xing Liu, Christos E. Athanasiou, Nitin P. Padture, Brian W. Sheldon, Huajian Gao
Summary: Data-driven approaches have the potential to revolutionize fracture mechanics by enabling accurate knowledge extraction and transfer, overcoming the challenges posed by data scarcity and unexplored connections between different fracture problems.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Energy & Fuels
Caiyuan Xiao, Guiju Zhang, Yudong Yu
Summary: This study numerically analyzes hydraulic fracturing processes in a multi-layered fractured reservoir, finding that fluid leakage rate increases with depth, linear equations can be derived for each layer, and the maximum opening pressure for fracturing increases with depth.
Article
Geosciences, Multidisciplinary
Yang Yang, Zixi Jiao, Longhuan Du, Hua Fan
Summary: Natural fractures in shale reservoirs pose challenges to hydraulic fracturing, but activating them can enhance fracturing effects and increase shale gas production. Geological conditions and operation parameters influence fracture network propagation and fracturing process. Optimizing construction parameters is key to increasing fracture network complexity.
FRONTIERS IN EARTH SCIENCE
(2021)
Article
Geosciences, Multidisciplinary
Matthew A. Thomas, Alejandro Mota, Benjamin M. Jones, R. Charles Choens, Jennifer M. Frederick, Diana L. Bull
FRONTIERS IN EARTH SCIENCE
(2020)
Article
Geosciences, Multidisciplinary
Rodrigo Chi-Duran, Margaret S. Avery, Nicholas Knezek, Bruce A. Buffett
GEOPHYSICAL RESEARCH LETTERS
(2020)
Article
Environmental Sciences
Sayedeh Sara Sayedi, Benjamin W. Abbott, Brett F. Thornton, Jennifer M. Frederick, Jorien E. Vonk, Paul Overduin, Christina Schadel, Edward A. G. Schuur, Annie Bourbonnais, Nikita Demidov, Anatoly Gavrilov, Shengping He, Gustaf Hugelius, Martin Jakobsson, Miriam C. Jones, DongJoo Joung, Gleb Kraev, Robie W. Macdonald, A. David McGuire, Cuicui Mu, Matt O'Regan, Kathryn M. Schreiner, Christian Stranne, Elena Pizhankova, Alexander Vasiliev, Sebastian Westermann, Jay P. Zarnetske, Tingjun Zhang, Mehran Ghandehari, Sarah Baeumler, Brian C. Brown, Rebecca J. Frei
ENVIRONMENTAL RESEARCH LETTERS
(2020)
Article
Geochemistry & Geophysics
B. A. Buffett
Summary: In this study, 3-D numerical calculations were used to assess the transition to turbulence in precessional flow, indicating that the transition to turbulence occurs near Re=500, higher than the typical value for stable Ekman layers. Complications due to fluid stratification or a magnetic field may suppress the transition to turbulence, reducing the likelihood of turbulent Ekman layers in the Earth's core.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
William K. Eymold, Jennifer M. Frederick, Michael Nole, Benjamin J. Phrampus, Warren T. Wood
Summary: Methane hydrates are solid structures containing methane that form under low temperature and high pressure conditions. This study developed a workflow to predict methane hydrate occurrence using statistical and machine learning methods. Results suggest that elevated hydrate formation is associated with high seafloor total organic carbon values at depths greater than 500 meters below sea level near Blake Ridge.
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2021)
Article
Geochemistry & Geophysics
Daniel A. Frost, Margaret S. Avery, Bruce A. Buffett, Bethany A. Chidester, Jie Deng, Susannah M. Dorfman, Zhi Li, Lijun Liu, Mingda Lv, Joshua F. Martin
Summary: In this study, an interdisciplinary analysis is used to co-constrain core-mantle boundary heat flow and test the thermal boundary layer theory. The seismic properties consistent with a thermal boundary layer are described, and support for the existence of a long-lived basal mantle molten layer through much of Earth's history is provided.
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2022)
Article
Geochemistry & Geophysics
William Davis, Bruce Buffett
Summary: Recent studies have shown that time variations in the Earth's axial magnetic dipole field are influenced by both deterministic and random elements, with the slowest decay mode and turbulent diffusion playing key roles. The amplitude and timescale of variations in dipole field generation, including contributions from both velocity and internal magnetic field variations, also have a significant impact on the field's behavior. Applying these findings to the palaeomagnetic field suggests that reversal rates are highly sensitive to changes in the field generation process.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Geosciences, Multidisciplinary
Rodrigo Chi-Duran, Margaret S. Avery, Bruce A. Buffett
Summary: The acceleration of Earth's magnetic field at high latitudes is attributed to waves in the core, with potential involvement of magnetic Rossby waves and zonal MAC waves. Observations suggest that these waves may propagate within a stratified layer at the top of the core, and the predicted stratification will lead to a slowing down and change in propagation direction of high-latitude features.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Geochemistry & Geophysics
B. A. Buffett, M. S. Avery, W. Davis
Summary: Observations of relative paleointensity reveal various asymmetries in the time dependence of the virtual axial dipole moment (VADM). Stochastic models are used to examine the origin of this behavior, and it is found that a model generating the dipole through a series of impulsive events in time can better explain the observed asymmetry.
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2022)
Review
Environmental Sciences
Benjamin W. Abbott, Michael Brown, Joanna C. Carey, Jessica Ernakovich, Jennifer M. Frederick, Laodong Guo, Gustaf Hugelius, Raymond M. Lee, Michael M. Loranty, Robie Macdonald, Paul J. Mann, Susan M. Natali, David Olefeldt, Pam Pearson, Abigail Rec, Martin Robards, Verity G. Salmon, Sayedeh Sara Sayedi, Christina Schadel, Edward A. G. Schuur, Sarah Shakil, Arial J. Shogren, Jens Strauss, Suzanne E. Tank, Brett F. Thornton, Rachael Treharne, Merritt Turetsky, Carolina Voigt, Nancy Wright, Yuanhe Yang, Jay P. Zarnetske, Qiwen Zhang, Scott Zolkos
Summary: Climate change poses a threat to the global permafrost domain, and protecting permafrost ecosystems is crucial for human rights, biosphere integrity, and global climate. Strengthened emissions reduction targets and support for local communities are necessary to preserve intact ecological communities and carbon sinks within the permafrost domain.
FRONTIERS IN ENVIRONMENTAL SCIENCE
(2022)
Article
Geochemistry & Geophysics
D. Holdenried-Chernoff, B. A. Buffett
Summary: Fluctuations in the paleomagnetic field suggest that the dipole decay time is shorter than expected. The short decay time can be explained by turbulent diffusion, and mean-field theory can quantitatively account for the dynamo results. The predicted decay time depends on the amplitude and length scale of the flow that interacts with the magnetic field. By extending these predictions to the paleomagnetic field, it is found that the inferred decay time requires a bulk root-mean-square velocity less than 0.8-1.2 mm/s.
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2022)
Article
Geochemistry & Geophysics
Quentin Nicolas, Bruce Buffett
Summary: Recent geomagnetic observations show localized oscillations in the field's secular acceleration at high latitudes with a period of about 20 years. This study examines the hypothesis that these observations are the result of MAC waves generated in Earth's core. By evaluating several generation mechanisms using dynamo simulations, the Lorentz force is found to be the most effective in producing high-latitude MAC waves with amplitudes consistent with observed oscillations.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2023)
Article
Geosciences, Multidisciplinary
Rodrigo Chi-Duran, Bruce A. Buffett
Summary: The rapid growth of magnetic-field observations through SWARM and other satellite missions has led to the development of new approaches for their analysis. The method of dynamic mode decomposition (DMD) is used in this study to analyze the geomagnetic radial field and its secular variation at high latitudes. The analysis reveals five modes, with one representing a slowly evolving background state and the other four describing a pair of waves. These waves have periods of approximately 19.1 and 58.4 years, and their characteristics are consistent with previous predictions and reports.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Physics, Multidisciplinary
Daria Holdenried-Chernoff, David A. King, Bruce A. Buffett
Summary: This paper introduces a stochastic fluid motion model for studying the generation of the geomagnetic field and obtains statistical properties similar to observations. This model helps to understand the long-term evolution of the geomagnetic field.
JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL
(2023)
Article
Geosciences, Multidisciplinary
Matthias Morzfeld, Bruce A. Buffett
NONLINEAR PROCESSES IN GEOPHYSICS
(2019)
