Conditions For Formation Research Articles

Origin of horsetail faults in an extensional regime using physical experiments for the Linnan Sag

Horsetail faults and rotational faults, which maintain slight differences, are all important identity markers for strike-slip movement. However, it is difficult to explain why horsetail faults also appear in the extensional regime. Using the Linnan Sag as a reference, physical experiments are conducted to reproduce the formation processes of horsetail faults in the extensional regime. Characteristics of these horsetail faults include: (1) horsetail faults are the product of strain superposition during two phases of noncoaxial extension; (2) preexisting faults generated in the initial stage may reactivate by the combined elongation of dip-slip motion, followed by oblique-slip faulting at the middle-late stage, thus becoming the principal fault of the horsetail faults; this initial distance is obviously less (approximately 46%) than its distance during the middle-late stage; (3) a large number of new dip-slip faults appear at the tip of the principal fault in the middle-late stage, spatially connecting with the principal fault to form the horsetail faults; and (4) other preexisting faults that intersect the principal fault are not necessary for forming the horsetail faults but their presence may make the principal fault prone to segmentation. Therefore, although horsetail faults in the extensional and strike-slip regimes are similar in shape, their formation conditions and fault properties are very different. Understanding the characteristics of the horsetail faults in the extension regime contributes to further study related to oil and gas migration and accumulation in the Petroliferous basin.

Shockingly Bright Warm Carbon Monoxide Molecular Features in the Supernova Remnant Cassiopeia A Revealed by JWST

We present JWST NIRCam (F356W and F444W filters) and MIRI (F770W) images and NIRSpec Integral Field Unit (IFU) spectroscopy of the young Galactic supernova remnant Cassiopeia A (Cas A) to probe the physical conditions for molecular CO formation and destruction in supernova ejecta. We obtained the data as part of a JWST survey of Cas A. The NIRCam and MIRI images map the spatial distributions of synchrotron radiation, Ar-rich ejecta, and CO on both large and small scales, revealing remarkably complex structures. The CO emission is stronger at the outer layers than the Ar ejecta, which indicates the re-formation of CO molecules behind the reverse shock. NIRSpec-IFU spectra (3–5.5 μm) were obtained toward two representative knots in the NE and S fields that show very different nucleosynthesis characteristics. Both regions are dominated by the bright fundamental rovibrational band of CO in the two R and P branches, with strong [Ar vi] and relatively weaker, variable strength ejecta lines of [Si ix], [Ca iv], [Ca v], and [Mg iv]. The NIRSpec-IFU data resolve individual ejecta knots and filaments spatially and in velocity space. The fundamental CO band in the JWST spectra reveals unique shapes of CO, showing a few tens of sinusoidal patterns of rovibrational lines with pseudocontinuum underneath, which is attributed to the high-velocity widths of CO lines. Our results with LTE modeling of CO emission indicate a temperature of ∼1080 K and provide unique insight into the correlations between dust, molecules, and highly ionized ejecta in supernovae and have strong ramifications for modeling dust formation that is led by CO cooling in the early Universe.

Spinel chromianowy z dunitów masywu Inagli i ich termobarometria tlenowa (tarcza ałdańska, platforma syberyjska)

The Inagli dunite-peridotite-shonkinite zonal-ring intrusive with platinum-chromite mineralization is located on the Aldan shield of the Siberian Platform. Considering the structure, rock composition and ore mineralization, it is similar to the platinum-bearing zonal massifs of the "Ural-Alaskan" type, but this intrusive differs from the latter in its geological position. In order to clarify the physical and chemical conditions of formation of the Inagli massif, the mineral composition of rocks, especially сhromite-containing dunites, peridotites and shonkinites, as well as platinum-chromitite ore segregations, has been studied in detail. The rocks of the Inagli massif, from dunites to shonkinites, including peridotites, clinopyroxenites, and alkaline syenites, form a single continuous series. This is confirmed by a clear dependence of the composition of olivine, pyroxene, phlogopite and chromian spinel on the content of MgO in rocks. They were formed from the initial high-potassium picrite melt, which, during rising, underwent gradual decompression solidification and formed a cylindrical diapir-like body at the near-surface level in the Early Cretaceous. This occurred as a result of subduction processes related to the formation of the Mongol-Okhotsk orogenic belt along the southern framing of the Siberian craton. The values of oxygen volatility (lgfO2) for dunites, peridotites, shonkinites, chromitites and olivine-chromite inclusions in the isoferroplatinum of the Inagli massif, calculated using the method of the olivine-spinel oxygen thermobarometer of Ballhaus-Berry-Green (BBG), form a single trend FMQ+(2-4) in the range 620-11400C, i.e. along the band by 2-4 units of lgfO2 exceeding the fayalite-magnetite-quartz (FMQ) buffer. Such a rather narrow range of variation in the values of O2 fugacity in a wide interval of temperature indicates good comparability and reliability of the data obtained. At the same time, there is a natural decrease in temperature intervals for the formation of olivine-chromite parageneses (in 0С): with isoferroplatinum – (1140-680); in chromitite segregations – (980-710); in dunites – (930-620); peridotites – (890-770) and shonkinites – (840-710). The results obtained almost completely coincide with the field of values for dunites and chromitites from the Platinum-bearing belt of the Urals, given by other researchers. In terms of redox parameters, platinum-bearing zonal ultramafic-mafic massifs of the Ural-Alaskan and Aldanian types are close to more oxidized peridotites with a long history in the lithosphere. They differ significantly from the peridotites of the Beni-Bousera massif, as well as abyssal peridotites of the oceanic ridge systems, and others, which are formed under more reduced conditions corresponding to the range between FMQ, carbon-oxygen-CO (ССО) and iron-wustite (IW) buffers.

Robust and comprehensive predictive models for methane hydrate formation condition in the presence of brines using black-box and white-box intelligent techniques

Accurate estimation of gas hydrate formation condition is crucial for many reasons. In one hand, the gas hydrate formation is a promising approach for gas separation, cold energy storage, seawater desalination, etc. On the other hand, in some industries, this phenomenon may cause some challenges, such as pipelines blockage. The current study was undertaken to develop trustworthy predictive tools for methane hydrate formation temperature (MHFT) in the presence of brines. To achieve this target, 1051 experimental data pertinent to the methane hydrate equilibrium in 26 single and multiple brines over an extensive range of operating conditions were amassed from published studies. Four simple factors, including pressure, brine concentration, salt molecular weight and salt melting temperature were defined as the input variables, and the black-box intelligent techniques, including gaussian process regression (GPR), multilayer perceptron (MLP) and radial basis function (RBF) were employed to link MHFT to the mentioned factors. A plethora of graphical and statistically-based assessments were performed to determine the accuracy level of the proposed models. While all intelligent models had excellent performances, the one established by the GPR method showed the best agreements with experimental data, and gave the AARE and R2 values of 0.14% and 99.17%, respectively, in the testing step. The foregoing model was capable of predicting MHFT over a broad range of conditions with relative deviations mostly below 0.10%. Additionally, it showed an excellent performance in describing the physical variations of MHFT versus operating factors. The authority of the analyzed databank and the presented model was asserted via the William's plot investigation. Moreover, a sensitivity analysis was undertaken in order to determine the most fundamental factors in controlling MHFT. Eventually, a simple mathematical correlation was also derived based on the white-box intelligent approach of gene expression programming (GEP), which allowed the accurate estimation of MHFT with an AARE of 0.56%.

Experience of Paleotectodynamic Analysis of Rank Components of Mesozoic-Cenozoic Movements and Deformations Using the Example of the Central Part of Bukharo-Khiva Region

The article describes the methodological basis and some first experience results of applying paleotectodynamic analysis of tectonic movements rank components and deformations to study the features of geological development of a certain territory of the Bukharo-Khiva region central part in the Mesozoic – Cenozoic. The relevance of the work is determined by the need to revise the traditional methods of historical and structural analysis, based on which the conditions of formation and age of oil and gas structural traps are determined to improve the reliability of prognostic works. Paleotectodynamic analysis, as a new direction of studying the geologic evolution history, provides an assessment of the duration of manifestation of tectodynamic systems (paleotectonic stresses, tectonic movements and deformations) of different ranks in geologic history, study of the paleotectonic development of rank components of tectonic movements and deformations in the intervals of tectodynamic system action, determination of the relative age of formation of structural elements, their inheritance, as well as determination of the relative age of formation of structural elements, their inheritance, role or contribution to the geological evolution.The main indicator, on the basis of which the possibility to identify an independent (integral) tectodynamic system is determined, is the stress field type and deformation regime. In the Mesozoic – Cenozoic of the western part of the Tien Shan, five phases of alternating change of tectonic stress fields of the first (for this region) rank and associated deformation regimes were identified. In the first approximation, they correspond to: Early – Middle Jurassic, Late Jurassic, Cretaceous, Paleogene, and Neogene-Quaternary time. On this basis, the paper substantiates the necessity to revise and modify the classical methods of historical-structural (paleotectonic) analysis, which should be performed for each rank component separately, taking into account the interaction of both peer-to-peer and multi-rank elements. In this approach, the most important indicator is the feedback sign between different rank elements of tectodynamic systems. On the example of the central part of the Bukharo-Khiva oil-and-gas-bearing region, paleotectonic maps-schemes of three ranks for the above-mentioned time intervals were obtained. The previously unknown features of the structural plans of different horizons and their evolution in the Mesozoic – Cenozoic history were established. They served as a basis for further traditional historical-structural analysis with the construction of isopachic triangles along the selected intervals for each rank component in order to assess the tectonic conditions and time of formation of anticlinal oil and gas traps.

Modern approaches to land resources valuation (on the example of Western Kazakhstan)

Western Kazakhstan is characterized by a large territory, extremely heterogeneous in terms of soil formation conditions and a complex soil cover structure. Its formation is also influenced by negative anthropogenic factors against the background of desertification. A soil map has been compiled. A methodology for an integrated approach to land resource assessment based on a genetic approach, taking into account the degree of soil degradation, has been substantiated.

Geodynamics and Ore Content of Proterozoic Maphites in the Central Part of the Aldan-Stanovoy Shield (Southern North Asian Craton)

The study of diverse mantle-derived igneous complexes is important for interpreting geodynamic events, ore deposits formation mechanisms, and ore-forming fluid sources. Modern studies of orogenic gold deposits in the Precambrian metamorphosed terranes emphasize the importance of subduction-enriched lithospheric mantle in the ore formation processes. Orogenic gold mineralization in the Nimnyr terrane of the Aldan-Stanovoy shield is confined to the outcrops of mafic granulites from the Medvedev complex, intruded and metamorphosed 1.92–1.90 Ga ago at the final stage of the collision process. The Medvedev complex and ore bodies are intersected by non-metamorphosed dolerites of the 1.87 Ga Timpton-Gynym and 1.75 Ga Timpton-Algamai dike belts formed under conditions of post-collisional and intracontinental extension. The mantle-derived igneous complexes, presenting in a variety of geodynamic settings and ore mineral formation stages, make it possible to identify compositional and evolutionary features of the mantle in connection with ore formation processes. To do this, there were determined rock-forming oxide and trace element concentrations in pre-ore mafic granulites of the Medvedev complex and post-ore dolerites. Based on the geochemical data, there was a reconstruction of rock and mantle source type formation conditions. It was found that the rocks of the Medvedev complex are plume-derived. Doleritic melt formation was contributed to by the subduction-enriched lithospheric mantle material. There is a possility of different degrees of source melting and interaction of plume with the enriched lithospheric mantle at the final stage of the collision process. The obtained results can be used to refine the geodynamic models of gold mineralization formation in the central part of the Aldan-Stanovoy shield. There has been proposed one of the standard models.

Integrated wellbore-reservoir modeling based on 3D Navier–Stokes equations with a coupled CFD solver

The occurrence of fluid flow near a wellhead is the major concern of the petroleum industry, as pressure drop, loss of formation, and other variables of interest are mostly affected in this region. The fluid flows from the hydrocarbon reservoir to the wellbore can be characterized as laminar to turbulent; thus, it is important to model this phenomenon with the integrated wellbore-reservoir model. Using 3D Navier–Stokes equations, an integrated wellbore-reservoir model is created in this study, and it incorporates the formation damage zone. For the porous-porous and porous-fluid interfaces, the General Grid Interface (GGI) approach is applied in conjunction with the conservative mass flux interface model. Model equations are solved using a velocity-pressure coupling solver that is pressure-based. For reliable and quick results, the system of equations is solved using an algebraic multigrid approach. The pressure diffusivity equation’s analytical solution under steady-state flow circumstances is used to validate the model. The integrated wellbore-reservoir model is applied to different reservoir scenarios, for example, different production rates, formation zones, and reservoir formation conditions. The results indicate that the present Computational Fluid Dynamics (CFD) model can be extended to simulate the real field scale model. integrated wellbore-reservoir modeling based on 3D Navier–Stokes equations with efficient computational techniques can lead the field of petroleum industries to advance current knowledge.

Data-driven estimation of battery state-of-health with formation features

Accurately estimating the state-of-health (SOH) of a battery is crucial for ensuring battery safe and efficient operation. The lifetime of lithium-ion batteries (LIBs) starts from their manufacture, and the performance of LIBs in the service period is highly related to the formation conditions in the factory. Here, we develop a deep transfer ensemble learning framework with two constructive layers to estimate battery SOH. The primary approach involves a combination of base models, a convolutional neural network to combine electrical features with spatial relationships of thermal and mechanical features from formation to subsequent cycles, and long short-term memory to extract temporal dependencies during cycling. Gaussian process regression (GPR) then handles SOH prediction based on this integrated model. The validation results demonstrate highly accurate capacity estimation, with a lowest root-mean-square error (RMSE) of 1.662% and a mean RMSE of 2.512%. Characterization on retired cells reveals the correlation between embedded formation features and their impact on the structural, morphological, and valence states evolution of electrode material, enabling reliable prediction with the corresponding interplay mechanism. Our work highlights the value of deep learning with comprehensive analysis through the relevant features, and provides guidance for optimizing battery management.

Evaluation of slow-release fertilizers derived from hydrogel beads: Sodium alginate-poly (acrylic acid) and humic acid-encapsulated struvite for soil salinity amelioration

Soil salinity, a severe environmental factor, significantly reduces the productivity of crop plants by increasing salt and mineral fertilizer concentrations in the soil. As a result, the development of sustainable slow-release mineral fertilizers (SRFs) is critical for addressing salt-affected soils. This study aimed to synthesize struvite (MgNH4PO4·6H2O) into hydrogel beads made from sodium alginate-poly (acrylic acid) in the absence (Sa@S) and presence (Sa@SHa) of humic acid (HA). The optimal conditions for struvite formation were at pH 9.0, resulting in a remarkable 73.21 %, 98.74 %, and 99.20 % for Mg, NH4-N and P removal, respectively. The SRFs study demonstrated that struvite had a significant release of Mg, P, and NH4-N, notably higher (P ≤ 0.05) than Sa@S and Sa@SHa. Experiments on swelling and soil water loss demonstrated that Sa@S yielded higher results in comparison to Sa@SHa. Furthermore, an experiment was conducted to study the impact of Sa@S and Sa@SHa on saline soil parameters over 20 days of incubation. The results showed both encapsulated struvite hydrogel beads reduced soil salinity, as indicated by the sodium adsorption ratio (SAR) and exchangeable sodium percentage (ESP). Additionally, a significant reduction (P ≤ 0.05) in soil electrical conductivity (EC) and sodium (Na) was observed for both hydrogel bead encapsulation treatments compared to the control soil. However, no apparent variance was observed in pH and soil organic carbon (SOC). Moreover, the levels of available phosphorus (P), ammonium-nitrogen (NH4-N), nitrate-nitrogen (NO3-N), cation exchange capacity (CEC), and exchangeable cations (Ca, Mg, K) in the soil were observed to be increased (P ≤ 0.05).

Developing evolutionary models for deformation band formation in high-porosity suprasalt sandstones: An example from Paradox Basin, Utah

Pervasive deformation adjacent to salt diapirs can drive significant porosity and permeability reduction in potential reservoir units, yet predicting the intensity and spatial distribution of these subseismic-scale features has remained as a persistent challenge. Previously, Jurassic sandstones adjacent to salt-cored anticlines in the Paradox Basin, eastern Utah, have been used to characterize deformation banding formation. However, these host rocks have undergone significant structural and diagenetic modification following band formation, which adds significant complexity to analyses of this type. Here, we integrate detailed structural transect analysis, petrologic analysis of bands and host rocks, depth-compaction relationships, critical state deformation models, and regional burial evolution models to constrain the timing and conditions of band formation. This analysis demonstrates that bands in this region formed prior to pervasive cementation and are generally expressed as two plastic strain gradients; one characterized by distributed deformation bands across the crest of salt-cored anticlines and a second wherein deformation band density increases near mesoscale normal faults. Comparison of these results with numerical structural evolution models of similar structures indicates that band gradients may have formed as a result of outer-arc extensional stress induced by the rising diapir and are linked with normal faults. These results highlight that the integration of material behaviors with kinematic evolution can constrain models for deformation band formation and may provide a useful workflow for understanding the development of these features in geologically young petroleum systems like those of the Atlantic passive margin.

The primary abundance of chondrules in CI chondrites

CI chondrites are the most significant extra-terrestrial samples for estimating the composition of primordial materials in the Solar System. However, CIs lose many primary features because of heavy parent body aqueous alteration. However, CI and CI-related Ryugu particles contain small amounts of relict anhydrous minerals, indicating primary occurrences of chondrules and refractory inclusions. In this study, we estimated the primordial abundance of chondrules in CIs from calculations of the bulk major element compositions. The constraints for the calculation were as follows: 1) CI chondrites primarily comprised chondrules, refractory inclusions, opaque minerals, and a matrix similar to other carbonaceous (C) chondrites. 2) The chemical compositions of these components were similar to those of the unaltered C chondrites. 3) The primary matrix composition of the CI was close to the mean bulk composition. 4) The alteration occurred isochemically. We used the mean major elemental compositions of chondrules and refractory inclusions in an almost unaltered chondrite, Y-81020, CO3.05. Our results were within the range of previously reported CI bulk chemical compositions in the case where chondrule abundances are ≲10 wt%. We also calculated the bulk chemical composition of Tagish Lake, ungrouped C2, which primarily contained ≲20 wt% chondrules. The CI chondrites and Tagish Lake were formed in the outer Solar System. The low primary abundance of chondrules in CIs is closely related to the formation conditions of chondrules in such regions. We suggest that dust with abundant ice and minor chondrules accreted onto the parent bodies of the CI and Tagish Lake in the outer Solar System. Primordial chondrule abundance is the key to clarifying the physical and chemical conditions and evolution of the early Solar System.

Dynamics of the Decomposition of Gas Molecules Containing Sulfur and Nitrogen from Char-S and Char-N Structures in Combustion and Pyrolysis Reactions

ABSTRACT Combustion states of char-S (C14H16O4S) and char-N (C18H19NO3) sub function molecules in a limited number of oxygen environments and pyrolysis states at high temperatures were examined quantum mechanically. In the study, the formation of all gases, with or without carbon, were determined. All the dynamics in which the O2 molecule could be effective in the combustion mechanism and all the elements that could affect the decomposition in the pyrolysis event were determined. The dynamics of the formation and disappearance of the highly stable CO molecule and CH2O (formaldehyde) molecules were shown in detail. It has been shown that the CO molecule is a catalysis that can bond with hydrocarbon groups and decompose them into small hydrocarbon groups at high temperature. In this study, it was shown that high temperature-dependent vibration and rotational energies, CO molecule and H-atom transfers play a role in the decomposition in the pyrolysis system, and the aromatic carbon ring group is the last particle group to decompose. In addition, the formation and dissociation dynamics of sulfoxylic acid, thioformic acid, hydrogen sulfide molecules originating from the Char-S system, as well as the formation conditions of hydrogen cyanide and pyridinyl molecules originating from the Char-N system, were determined. The study also showed that since the N-atom is located in the aromatic carbon ring, it makes the emergence of the nitrous oxide molecule difficult in pyrolysis systems.

Promoting thermodynamic stability of hydrogen hydrates with gas-phase modulators for energy-efficient blue hydrogen storage

As the global climate crisis intensifies with rising carbon dioxide (CO2) concentrations, blue hydrogen (H2) produced through the integration of CO2 capture technologies is emerging as a promising alternative energy source and is challenging traditional fossil fuels in the de-fossilization paradigm. Gas hydrate could be one of the feasible storage medium for energy-efficient H2 storage, due to its potential for eco-friendly features and high H2 storage capacity. However, extreme thermodynamic formation conditions for pure H2 hydrate need to be mitigated for practical application. Here, we demonstrate a novel approach by blending a ‘gas-phase modulator’ with H2, specifically a C2H6 (70%) + C3H8 (30%), to enable hydrate-based H2 storage under moderate thermodynamic formation conditions. In this study, we systematically examined thermodynamic stability, crystallographic structure, guest occupation behavior, and the formation kinetics of the C2H6 + C3H8 + H2 hydrates by varying the H2 composition. The results revealed that the C2H6 + C3H8 mixture played a notable role in promoting thermodynamic formation condition of H2 hydrates. The mixed C2H6 + C3H8 + H2 hydrates were predominantly comprised of sII hydrate, with small amount of sI hydrate. Considering the small to large cage ratio of sI and sII hydrate, this observation indicates a significant advantage for H2 storage due to primarily occupation behavior of H2 into the small cages. In addition, as the H2 composition in the feed gas increased, we confirmed that not only that H2 storage in the hydrate was enhanced but also that the degree of the H2 enclathration ratio into the hydrate was elevated. Moreover, the maximum composition of H2 in the C2H6 (14%) + C3H8 (6%) + H2 (80%) hydrate was 44.37%. Hence, we believe that our findings can contribute valuable insights into the potential application of gas-phase modulators for hydrate-based H2 storage, we emphasize that C2H6 + C3H8 can act as a potential gas-phase modulator for energy-efficient H2 storage.

Reconstructing the depositional environment and diagenetic modification of global phosphate deposits through integration of uranium and strontium isotopes

The geochemistry of phosphate rocks can provide valuable information on their depositional environment and the redox condition of global oceans through time. Here we examine trace metal concentrations and uranium (δ238U, δ234U) and strontium (87Sr/86Sr) isotope variations of marine sedimentary phosphate rocks and the phosphate-bearing carbonate fluorapatite (CFA) mineral phase, originating from Precambrian to mid-Miocene aged major global phosphate deposits. We find elevated concentrations of several trace elements (Al, V, Cr, Cd, U, Mn, Co, Cu, As, and Rb) in the CFA mineral phase of young phosphate rocks (Miocene to Late Cretaceous) relative to those of older (Devonian to Precambrian) rocks. The δ238U of phosphate rocks of Mid-Miocene to Permian age range from −0.311‰ to 0.070‰, exhibiting a positive fractionation relative to modern seawater (−0.38‰). This is similar to the isotope fractionation reported for carbonate and shale sediments, likely resulting from the reduction of uranium in porewaters during CFA precipitation. Cambrian to Precambrian phosphate rocks have lower δ238U of −0.583‰ to −0.363‰, indicating different depositional redox conditions likely resulting from seafloor anoxia and/or diagenetic modification. The 87Sr/86Sr ratios of phosphate rocks of Cretaceous to Mid-Miocene age generally follow the secular 87Sr/86Sr seawater curve. Phosphate rocks with 87Sr/86Sr that deviate from this curve have characteristic trace metal trends, such as lower Sr/Ca and Sr concentrations, suggesting later diagenetic modification. Older phosphate rocks of Precambrian age are systematically more radiogenic than the expected secular Sr seawater composition at the time of deposition, possibly due to the greater influence of terrestrial input in peritidal zones and/or more pervasive diagenetic modification. Overall, our study reveals connections between U and Sr isotope variations for reconstructing the depositional and diagenetic conditions of global phosphate rock formation through Earth history and the transition to an oxic ocean following the Paleozoic Oxygenation Event.

THE SIGNIFICANCE OF THE PLEISTOCENE AQUATIC FAUNA OF MOLLUSKS FOR THE REPRODUCTION OF SEDIMENTATION CONDITIONS IN WESTERN UKRAINE

The territory of Western Ukraine is characterized by the development of a wide range of genetic types of continental formations. The Carpathian Mountain Country (properly the Carpathians, East Carpathian Foreland, and Transcarpathia) and the highly fragmented parts of the Volhynia and Podolia Uplands are characterized by a special diversity. The time range of their formation is vast – from the Early Pleistocene to the present. The complexity of the structure of the Quaternary sequence gives rise to discussions about the origin of some components of anthropogenic accumulations. Despite the fact that most of the challenging issues have already been resolved, we find debatable information in the works of some researchers of the 20th and even the 21st centuries about the aqueous origin of the thick sequences of anthropogenic sediments covering the terraces of the Dniester and Dnieper basins. The researchers use many methods to solve the issue of the deposit genesis. Some of them are based on the study of paleontological (including paleomalacological) remains, which are often found in both aqueous (alluvial, lake, swamp) and aerial (primarily loess) formations. Malacofauna has been used since the second half of the 19th century to determine the age, conditions of formation, and origin of the deposits. To establish the origin of sediments we have used the mollusk fauna in this work, which can be often found in the formations of the studied territory. The interpretation of the fauna is debatable in the sections where several genetic types of formations are exposed, primarily alluvial and eolian–deluvial loess. This type of combination of deposits is found in outcrops on the numerous terraces of the Dniester and the terraces of its East Carpathian Foreland’s and Podolia tributaries. The results of the research obtained by us using paleomalacological studies correlate well with data obtained using other methods. Such methods include actual field observations, as well as lithological, palaeopedological, paleontological (study of fossil mammals, fish, spores, and pollen), archaeological, and other methods. The results presented in this work made it possible to establish the genesis of some components of polygenetic complex strata, as well as testify to the effectiveness of the applied research method. Keywords: anthropogen; malacofauna; alluvium; loess; paleogeography; Podolia; East Carpathian Foreland.

Analytical Prediction of Gas Hydrate Formation Conditions for Oil and Gas Pipeline

Analytical Prediction of Gas Hydrate Formation Conditions for Oil and Gas Pipeline

Two rhombic ice phases from aqueous salt solutions under graphene confinement.

Water exhibits rich ice phases depending upon its respective formation conditions, and in particular, the two-dimensional ice with nonhexagonal symmetry adsorbed on solids relates to the exceptional arrangement of water molecules. Despite extensive reporting of two-dimensional ice on various solid surfaces, the geometry and thermodynamics of ice formation from an aqueous salt solution are still unknown. In this Letter, we show the formation of single- and two-phase mixed two-dimensional rhombic ice from aqueous salt solutions with different concentrations under strong compressed confinement of graphene at ambient temperature by using classical molecular dynamics simulations and first-principles calculations. The two rhombic ice phases exhibit identical geometry and thermodynamic properties, but different projections of the oxygen atoms against solid surface symmetry, where they relate to the stable and metastable arrangements of water molecules confined between two graphene layers. A single-phase rhombic ice would grow from the confined saturated aqueous solutions since the previously stable rhombic molecular arrangement becomes an unstable high-energy state by introducing salt ions nearby. Our result reveals different rhombic ice phases growing from pure water and aqueous solutions, highlighting the deciding role of salt ions in the ice formation process due to their common presence in liquids.

Coupled redox cycling of arsenic and sulfur regulates thioarsenate enrichment in groundwater

High‑arsenic groundwater is influenced by a combination of processes: reductive dissolution of iron minerals and formation of secondary minerals, metal complexation and redox reactions of organic matter (OM), and formation of more migratory thioarsenate, which together can lead to significant increases in arsenic concentration in groundwater. This study was conducted in a typical sulfur- and arsenic-rich groundwater site within the Datong Basin to explore the conditions of thioarsenate formation and its influence on arsenic enrichment in groundwater using HPLC-ICPMS, hydrogeochemical modeling, and fluorescence spectroscopy. The shallow aquifer exhibited a highly reducing environment, marked by elevated sulfide levels, low concentrations of Fe(II), and the highest proportion of thioarsenate. In the middle aquifer, an optimal ∑S/∑As led to the presence of significant quantities of thioarsenate. In contrast, the deep aquifer exhibited low sulfide and high Fe(II) concentration, with arsenic primarily originating from dissolved iron minerals. Redox fluctuations in the sediment driven by sulfur‑iron minerals generated reduced sulfur, thereby facilitating thioarsenate formation. OM played a crucial role as an electron donor for microbial activities, promoting iron and sulfate reduction processes and creating conditions conducive to thioarsenate formation in reduced and high‑sulfur environments. Understanding the process of thioarsenate formation and the influencing factors is of paramount importance for comprehending the migration and redistribution of arsenic in groundwater systems.

Real-time diagnosis and monitoring of biofilm and corrosion layer formation on different water pipe materials using non-invasive imaging methods

Water distribution networks play a crucial role in ensuring a reliable water supply, yet they encounter challenges such as corrosion, scale formation, and biofilm growth due to interactions with environmental elements. Biofilms and corrosion layers are significant contaminants in water pipes, formed by complex interactions with pipe materials. As the structure of these contamination layers varies depending on the pipe material, it is essential to investigate the contamination layer for each material individually. Specifically, biofilm growth is typically investigated concerning organic sources, while the growth of humus layers is examined in relation to inorganic elements such as manganese (Mn), iron (Fe), and aluminum (Al), which are major elements and organic substances found in water pipes. Real-time imaging of recently contaminated layers can provide important insights to improve system performance by optimizing operations and cleaning processes. In this study, cast iron (7.10 ± 0.78 nm) exhibits greater surface roughness compared to PVC (5.60 ± 0.14 nm) and provides favorable conditions for biofilm formation due to its positive charge. Over a period of 425 h, the fouling layer on cast iron and PVC surfaces gradually increased in fouling thickness, porosity, roughness, and density, reaching maximum value of 29.72 ± 3.6 μm, 11.44 ± 1.1%, 41673 ± 1025.6 pixels, and 0.80 ± 0.3 fouling layer pixel/layer pixel for cast iron, and 8.15 ± 0.4 μm, 20.64 ± 0.9%, 35916.6 ± 755.7 pixels, and 0.58 ± 0.1 fouling layer pixel/layer pixel, respectively. Within the scope of the current research, CNN model demonstrates high correlation coefficients (0.98 and 0.91) in predicting biofilm thickness for cast iron and PVC. The model also presented high accuracy in predicting porosity for both materials (over 0.91 for cast iron and 0.96 for PVC). While the model accurately predicted biofilm roughness and density for cast iron (correlation coefficients 0.98 and 0.94, respectively), it had lower accuracy for PVC (correlation coefficients 0.92 for both parameters).