Explore the vast range of titles available.

Eddavidite is a new mineral species (IMA2018-010) with ideal formula, Cu[sub.12]Pb[sub.2]O[sub.15]Br[sub.2], and cubic Fm3¯m symmetry: a = 9.2407(9) Å; V = 789.1(2) Å[sup.3]; Z = 2. Eddavidite is the bromine analog of murdochite, Cu[sub.12]Pb[sub.2]O[sub.15]Cl[sub.2], with which it forms a solid solution series. The type locality is the Southwest mine, Bisbee, Cochise County, Arizona, U.S.A. Eddavidite also occurs in the Ojuela mine, Mapimí, Durango, Mexico. Eddavidite occurs as domains within mixed murdochite–eddavidite crystals. The empirical formula, normalized to 12 Cu apfu, is Cu[sub.12](Pb[sub.1.92]Fe[sub.0.06]Si[sub.0.06])(O[sub.15.08]F[sub.0.02])-(Br[sub.0.99]Cl[sub.0.89]☐[sub.0.12]). Type locality samples contain up to 67% eddavidite component, while Ojuela mine samples contain up to 62%. Mixed eddavidite–murdochite crystals show forms 100 and 111; the habit grades from cubic through cuboctahedral to octahedral. Mixed eddavidite–-murdochite crystals exhibit good cleavage on 111. Eddavidite is black, opaque with submetallic luster, and visually indistinguishable from intergrown murdochite. Its Mohs hardness is 4; d[sub.meas.] = 6.33 g/cm[sup.3], d[sub.calc.] = 6.45 g/cm[sup.3]. The crystal structure, refined to R = 0.0112, consists of corner-sharing square planar CuO[sub.4] units, arranged in Cu[sub.12]O[sub.24] metal oxide clusters, which encapsulate Br atoms. PbO[sub.8] cubes share edges with Cu[sub.12]O[sub.24] clusters in a continuous framework. Eddavidite incorporates bromine remaining after desiccation of paleo-seawater at its two known localities, which were both once situated along the Western Interior Seaway.

The development of inherently safe energy devices is a key challenge, and aqueous Li-ion batteries draw large attention for this purpose. Due to the narrow electrochemical stable potential window of aqueous electrolytes, the energy density and the selection of negative electrode materials are significantly limited. For achieving durable and high-energy aqueous Li-ion batteries, the development of negative electrode materials exhibiting a large capacity and low potential without triggering decomposition of water is crucial. Herein, a type of a negative electrode material (i.e., LiₓNb2/7Mo3/7O₂) is proposed for high-energy aqueous Li-ion batteries. LiₓNb2/7Mo3/7O₂ delivers a large capacity of ∼170 mA · h · g−1 with a low operating potential range of 1.9 to 2.8 versus Li/Li⁺ in 21 m lithium bis(trifluoromethanesulfonyl)amide (LiTFSA) aqueous electrolyte. A full cell consisting of Li1.05Mn1.95O₄/Li9/7Nb2/7Mo3/7O₂ presents high energy density of 107 W · h · kg−1 as the maximum value in 21 m LiTFSA aqueous electrolyte, and 73% in capacity retention is achieved after 2,000 cycles. Furthermore, hard X-ray photoelectron spectroscopy study reveals that a protective surface layer is formed at the surface of the negative electrode, by which the high-energy and durable aqueous batteries are realized with LiₓNb2/7Mo3/7O₂. This work combines a high capacity with a safe negative electrode material through delivering the Mo-based oxide with unique nanosized and metastable characters.

The tight carbonate reservoir was controlled by various geological factors, and such factors played different roles in buried depths and formations. Therefore, studies related to the factors controlling carbonate reservoir distribution are of great significance for the prediction and evaluation of high-quality dolostone reservoirs. In this paper, we focus on the controlling factor of the submember Ma5[sub.5] dolostone reservoir in the western Ordos Basin. The main rock types, reservoir pores, physical properties, and pore structure characteristics of the reservoir were analyzed by thin section identification, physical property analysis, and mercury injection, respectively. Then, the main controlling factors of reservoir development were comprehensively analyzed from the perspectives of palaeostructure, lithofacies palaeogeography, diagenesis, and diagenetic facies. The results show that two kinds of dolostone reservoirs in the submember Ma5[sub.5] developed in the western Ordos Basin, including intercrystalline pore-type and dissolution pore-type. The former reservoir is primarily characterized by powder-fine dolostone with residual structure, dolomite intercrystalline pore, and micropore with porosity ranging from 2% to 11%. There are three types of pore structures developed in it, such as macropore-medium throat-single peak (MAMS), macropore-fine throat-single peak (MAFS), and medium pore-fine throat-single peak (MEFS). The latter reservoir is mainly featured by powdery crystalline dolostone with gypsum and halite dissolution, moldic pore, and dissolved pore between breccias with a porosity greater than 5%. It consists of two types of pore structures, such as macropore-fine throat-single peak (MAFS) and medium pore-coarse throat-multipeak (MECM). The intercrystalline pore-type dolostone reservoir is mainly controlled by the lithofacies palaeogeographic environment and diagenesis. In specific, the shoal microfacies at the edge of the platform and the active reflux seepage dolomitization are the basic sedimentary environment conditions for reservoir formation and the key to reservoir formation, respectively. The dissolution pore-type dolostone reservoir is primarily influenced by both paleostructure and diagenesis. The relatively high part of the paleostructure provides favorable conditions for the formation of evaporate minerals, and early freshwater dissolution is the key to reservoir formation. This research will provide a theoretical basis for forecasting the favorable distribution areas of different types of dolostone reservoirs.

Rock salt is considered a suitable medium for the permanent disposal of heat‐generating radioactive waste due to its isolation properties. However, excavation damage and heating induce complex and heterogeneous thermal‐hydrological‐mechanical (THM) processes across different zones. Quantifying this heterogeneity is crucial for accurate long‐term performance assessment models, but traditional methods lack the necessary resolution. This study employs 4D electrical resistivity tomography (ERT) monitoring during controlled heating experiments in a salt formation to unravel the spatiotemporal dynamics of THM processes. Advanced time‐lapse inversion and clustering analysis quantify subsurface properties and map the heterogeneity of THM dynamics. The ERT results can estimate subsurface properties and delineate the damaged and intact zones, enabling appropriate parameterization and representation of processes for long‐term modeling. This approach may be used in further improving the predictive models and ensuring the safe long‐term disposal of radioactive waste in rock salt.

Rock salt has excellent properties for its use as underground leak‐proof containers for the storage of renewable energy. Salt solution mining has long been used for salt mining, and can now be employed in the construction of underground salt caverns for the storage of hydrogen gas. This paper presents a wide range of methods to study the mineralogy, geochemistry, microstructure and geomechanical characteristics of rock salt, which are important in the engineering of safe underground storage rock salt caverns. The mineralogical composition of rock salt varies and is linked to its depositional environment and diagenetic alterations. The microstructure in rock salt is related to cataclastic deformation, diffusive mass transfer and intracrystalline plastic deformation, which can then be associated with the macrostructural geomechanical behavior. Compared to other types of rock, rock salt exhibits creep at lower temperatures. This behavior can be divided into three phases based on the changes in strain with time. However, at very low effective confining pressure and high deviatoric stress, rock salt can exhibit dilatant behavior, where brittle deformation could compromise the safety of underground gas storage in rock salt caverns. The proposed review presents the impact of purity, geochemistry and water content of rock salt on its geomechanical behavior, and thus, on the safety of the caverns. The safety of underground hydrogen storage in rock salt caverns needs to be guaranteed. This review paper presents the impact of purity, geochemistry and water content of rock salt on its geomechanical behavior, and thus, on the safety of the caverns. A wide range of methods that are applied to investigate the mineralogy, geochemistry, microstructures and geomechanics are covered. Highlights Hydrogen may become indispensable in the transition to renewable energy Rock salt caverns may provide leak‐proof containers for hydrogen storage Mineralogical composition links with depositional environment and diagenesis Microstructure links to cataclastic deformation, diffussive mass transfer and intracrystalline plastic deformation Geomechanical behavior of rock salt is influenced by its composition and impurities

The paper aims to give a universal methodology for assessing the storage capacity of a bedded rock salt formation in terms of the operational and strategic storage facilities for liquid fuels. The method assumes the development of a geological model of the analyzed rock salt formation and the determination of the salt caverns’ size and spacing and the impact of convergence on their capacity during operation. Based on this method, the paper presents calculations of the storage capacity using the example of the bedded rock salt formations in Poland and their results in the form of storage capacity maps. The maps show that the analyzed rock salt deposits’ storage capacity in northern Poland amounts to 7.1 B m3 and in the Fore-Sudetic Monocline to 10.5 B m3, in the case of strategic storage facilities. The spatial analysis of the storage capacity rasters, including determining the raster volumes and their unique values, allowed us to quantify the variability of the storage capacity in the analyzed rock salt deposits.

A vanadium ion valence state constant high-entropy perovskite system was synthesized using the hydrothermal method with a trivalent vanadium ion as the vanadium source. The B-site of the perovskite crystal lattice was loaded with five atoms in equal proportions. We tried to synthesize the Sr(TiZrHfVNb)O[sub.3] high-entropy system using different methods. However, the valence state of the vanadium ion could only be kept constant using the hydrothermal process in the valence balanced high-entropy composition system. There was significant vanadium element segregation and second phase in the Sr(TiZrHfVNb)O[sub.3] system prepared using the solid-state reaction process. Also, obvious vanadium ion valence state ascending from V[sup.3+] to V[sup.5+] appeared in this high-entropy system with an increase in calcination temperature. Inconspicuous vanadium element segregation appeared at 900 °C, the significant segregation phenomenon and second phase appeared at 1200 °C, and the particle size increased with the temperature. This meant that the high-entropy value could not only stabilize the crystal phase, but also stabilize the ionic valence state. Moreover, the constant trivalent vanadium ion valence state could provide coordinated performance with a wide optical response range and a low band gap for the high-entropy system. This suggests that the system might grow a potential ceramic material for optical applications.