Abhinav Prakash Gahlot, Rafael Orozco, Felix J. Herrmann
Geological Carbon Storage (GCS) is a key technology for achieving global climate goals by capturing and storing CO2 in deep geological formations. Its effectiveness and safety rely on accurate monitoring of subsurface CO2 migration using advanced time-lapse seismic imaging. A Digital Shadow framework integrates field data, including seismic and borehole measurements, to track CO2 saturation over time. Machine learning-assisted data assimilation techniques, such as generative AI and nonlinear ensemble Bayesian filtering, update a digital model of the CO2 plume while incorporating uncertainties in reservoir properties. Compared to 2D approaches, 3D monitoring enhances the spatial accuracy of GCS assessments, capturing the full extent of CO2 migration. This study extends the uncertainty-aware 2D Digital Shadow framework by incorporating 3D seismic imaging and reservoir modeling, improving decision-making and risk mitigation in CO2 storage projects.
Jimmy Xuekai Li, Thomas Flottmann, Max Millen
et al.
This study presents a novel sonic mapping method applied to coal samples, verified by CT scan imaging. Cubic coal samples with side lengths of 50-70 mm were subjected to non-destructive sonic tests, measuring both P-wave (Vp) and S-wave (Vs) velocities. Each of the three orthogonal directions (X, Y, and Z) of the cube was divided into 9 regions, resulting in 27 Vp and 27 Vs measurements per sample. From these data, 2D sonic maps were constructed for each direction, and interpolation was employed to refine the mappings. A 3D sonic map was then generated by averaging the 2D maps. The 3D sonic mapping results were compared and validated against high-resolution CT scan images, confirming the reliability of this approach for mapping the internal structure of coal samples.
Combined analyses of the Higgs boson production and decay rates as well as its coupling strengths to vector bosons and fermions are presented. The combinations include the results of the analyses of the H → γγ, ZZ∗, WW∗, Zγ, bb, ττ and μμ decay modes, and the constraints on the associated production with a pair of top quarks and on the off-shell coupling strengths of the Higgs boson. The results are based on the LHC proton-proton collision datasets, with integrated luminosities of up to 4.7 fb-1 at √S =7 TeV and 20.3 fb-1 at √S = 8 TeV, recorded by the ATLAS detector in 2011 and 2012. Combining all production modes and decay channels, the measured signal yield, normalised to the Standard Model expectation, is 1.18+0.15 -0.14. The observed Higgs boson production and decay rates are interpreted in a leading-order coupling framework, exploring a wide range of benchmark coupling models both with and without assumptions on the Higgs boson width and on the Standard Model particle content in loop processes. The data are found to be compatible with the Standard Model expectations for a Higgs boson at a mass of 125.36 GeV for all models considered.
AbstractA semi-analytical and a finite-difference scheme are presented for the simulation of temperature and the heat transfer in a multi-segment coaxial borehole heat exchanger. The single-segment solution on closed-form is extended to a semi-analytical multi-segment solution, where each segment may have unique properties. These properties are such as different casings, widths of the annulus, radius of the inner tubing, material properties, rock properties and geothermal gradients. The multi-segment model is a simple and powerful alternative to numerical methods for simulating a complex coaxial borehole heat exchanger with a constant flow rate. It is demonstrated with a deep coaxial borehole heat exchanger made of three different segments. The analytical and semi-analytical models are validated by comparison with numerical solutions obtained with an upstream finite difference scheme. The match between the solutions is excellent. The solution on a closed-form is used to study the temperature difference between the outlet and the inlet regarding two dimensionless numbers. It is found that the maximum temperature difference occurs when the dimensionless heat transfer coefficient for the casing-rock is much larger than one. A second necessary condition is that the dimensionless heat transfer coefficient for the insulator between the inner tube and the annulus must be much less than one. The power leakage from the inner tubing to the annulus is also at a maximum under these conditions.
Monitoring the performance of humidity sensors has become particularly relevant due to the lack of in-house production of humidity sensors in the Russian Federation and the logistical problems that have arisen. Humidity is subject to high spatial variability, therefore, standard methods for monitoring data quality based on the difference with the field of the first approximation are not applicable for its control. It is proposed to carry out monitoring by comparing readings on the surface and at altitude with a pressure of 850 hPa, where humidity is less than 60% in the absence of low clouds, and more than 70% in its presence. The fact of the presence/absence of low clouds is determined by the readings of a vertically oriented pyrometer. The difference between the air temperature at the surface and the temperature from the pyrometer of more than 14°K corresponds to the absence of low clouds, and less than 14°K corresponds to the presence of low clouds. Accordingly, a serviceable humidity sensor should show the appropriate values.
There is a growing concern that a big coronal mass ejection event will induce perturbations on the power supply of fiber optic transoceanic cables that may produce a global internet blackout. In this paper we give the expression of the voltage variations that a transient change of the geomagnetic field induces on the voltage of the power supply of a transoceanic fiber optic cable. We show that the transient voltage change is proportional to the magnitude of the magnetic field deviations and not to its time derivative as a direct application of Faraday's law would imply, and this suggests design criteria to protect transoceanic fiber optic systems against big geomagnetic storm events. The presented analysis also enables the classification of existing systems into some that are less sensitive to the weakening of the geomagnetic field occurring during strong geomagnetic storms and others that are more prone to experience an outage when a weakening of the geomagnetic field occurs.
Over its multibillion-year history, the Earth has experienced a wide range of climates. The long-term climate is controlled by the atmospheric carbon dioxide concentration, which is regulated by marine sequestration through chemical weathering. This chemical weathering sink is strongly linked to the distribution and composition of the continents. However, the effect of continental distribution has never been studied within a general framework. Here we show that the global weathering rate is sensitive to the size and shape of the continents, but is not well explained by the amount of land in the tropics. We construct synthetic continental configurations and use an ensemble of global climate model simulations to isolate the expected effect of continental arrangement on weathering and carbon burial. Runoff patterns are complex, sensitive to detailed features of continental geometry, and poorly predicted by continental latitude. These results help explain the long-term variability and irregularity of Earth's climate.
We have used pH-, Na-, and Cl-sensitive microelectrodes to study basolateral HCO3- transport in isolated, perfused proximal tubules of the tiger salamander Ambystoma tigrinum. In one series of experiments, we lowered basolateral pH (pHb) from 7.5 to 6.8 by reducing [HCO3-]b from 10 to 2 mM at a constant pCO2. This reduction of pHb and [HCO3-]b causes a large (approximately 0.35), rapid fall in pHi as well as a transient depolarization of the basolateral membrane. Returning pHb and [HCO3-]b to normal has the opposite effects. Similar reductions of luminal pH (pHl) and [HCO3-]l have only minor effects. The reduction of [HCO3-]b and pHb also produces a reversible fall in aiNa. In a second series of experiments, we reduced [Na+]b at constant [HCO3-]b and pHb, and also observed a rapid fall in pHi and a transient basolateral depolarization. These changes are reversed by returning [Na+]b to normal. The effects of altering [Na+]l in the presence of HCO3-, or of altering [Na+]b in the nominal absence of HCO3-, are substantially less. Although the effects on pHi and basolateral membrane potential of altering either [HCO3-]b or [Na+]b are largely blocked by 4-acetamido-4-isothiocyanostilbene-2,2'-disulfonate (SITS), they are not affected by removal of Cl-, nor are there accompanying changes in aiCl consistent with a tight linkage between Cl- fluxes and those of Na+ and HCO3-. The aforementioned changes are apparently mediated by a single transport system, not involving Cl-. We conclude that HCO3- transport is restricted to the basolateral membrane, and that HCO3- fluxes are linked to those of Na+. The data are compatible with an electrogenic Na/HCO3 transporter that carries Na+, HCO3-, and net negative charge in the same direction.
We investigate the effect of pressure, temperature and acidity on the composition of water-rich carbon-bearing fluids at thermodynamic conditions that correspond to the Earth's deep Crust and Upper Mantle. Our first-principles molecular dynamics simulations provide mechanistic insight into the hydration shell of carbon dioxide, bicarbonate and carbonate ions, and on the pathways of the acid/base reactions that convert these carbon species into one another in aqueous solutions. At temperature of 1000 K and higher our simulations can sample the chemical equilibrium of these acid/base reactions, thus allowing us to estimate the chemical composition of diluted carbon dioxide and (bi)carbonate ions as a function of acidity and thermodynamic conditions. We find that, especially at the highest temperature, the acidity of the solution is essential to determine the stability domain of carbon dioxide, bicarbonate and carbonate ions.
The annual temperature cycle of the earth closely follows the annual cycle of solar flux. At temperate latitudes, both driving and response cycles are well described by a strong annual sinusoidal component and a non-vanishing semiannual component. A new analysis of historical weather station records in the United States determines persistent annual and semiannual variation with high precision. Historical annual temperature ranges are consistent with prior studies. Semiannual temperature cycles were much stronger than expected based on the semiannual solar driving. Instead, these cycles were consistent with multiplicative effects of two annual cycles. Our methods provide a quantitative window into the climate's nonlinear response to solar driving, which is of potential value in testing climate models.