Search Results (46)

Calcareous interbeds are widely developed in marine clastic sequences, where laterally continuous, tight calcareous interbeds act as critical controls on the formation of lithologic traps and the distribution of oil. However, the genetic mechanisms and development models of these interbeds, particularly under deep-burial conditions subject to complex fluid interactions, remain poorly understood. Using the Donghe Sandstone in the Hade Oilfield (Tarim Basin) as a case study, this paper investigates the genetic evolution of calcareous interbeds via an integrated approach combining core observation, thin-section petrography, scanning electron microscopy (SEM), stable isotope analysis, fluid inclusion microthermometry, and heavy fraction analysis. The results indicate that: (1) The carbonate cements within the interbeds are compositionally complex, dominated by calcite but characterized by a diagnostic assemblage of anhydrite, ferroan calcite, and ankerite. (2) During the depositional to shallow burial stages, seawater evaporation and meteoric freshwater influx led to the supersaturation of calcium-rich pore waters near the surface. This facilitated the precipitation of early cement assemblages, which are predominantly of freshwater origin and consist mainly of non-ferroan calcite nodules, dolomite, and anhydrite. (3) During the deep burial stage, the injection of high-salinity brines and organic acid decarboxylation triggered Thermochemical Sulfate Reduction (TSR). This process caused the extensive consumption of the pre-existing anhydrite and the formation of authigenic pyrite, followed by the tight occlusion of remaining porosity through the precipitation of late-stage ferroan calcite and ankerite. (4) In the broad slope setting, these tight calcareous interbeds constitute effective flow barriers, resulting in a stepped distribution of the oil–water contact. Within the reservoir compartments segmented by these interbeds, crude oil maturity exhibits a distinct inversion (i.e., higher maturity below the interbeds and lower maturity above), confirming the critical sealing capacity of the interbeds during hydrocarbon accumulation. Ultimately, this study establishes a genetic model coupling calcareous interbed development with deep-burial fluid alteration, providing new geological insights for predicting subtle traps in marine sandstone reservoirs. Full article

This study investigates the evolution and influencing factors of non-metallic inclusions in industrial pipeline steel during the vacuum degassing (VD) process. Steel and slag samples were systematically collected at multiple intervals throughout the vacuum treatment using an automated robotic sampler, which integrated temperature measurement and sampling functions. The results indicate that the molten steel temperature and the concentrations of nitrogen, oxygen, and sulfur exhibited an overall decreasing trend, with removal kinetics characterized by a rapid initial reduction followed by a gradual stabilization. The dominant inclusion phases were identified as Mg-Al spinel and calcium aluminates. Specifically, the top slag composition was distributed within the C₃A phase field, trending toward the liquid C₁₂A₇ region, while the endogenous inclusions transitioned from CA₂ toward CA. With prolonged vacuum treatment, the relative fraction of calcium aluminates progressively increased at the expense of Mg-Al spinel due to continuous slag-metal reactions. Furthermore, quantitative analysis reveals that the population density of small equivalent circular diameter (ECD) inclusions continuously decreased, while the average inclusion size increased, indicating that the VD process promotes the collision and coalescence of inclusions. Full article

This work investigates the synthesis, thermodynamic phase stability and microstructural, mechanical and tribological behavior of the CrFeMoV alloy system and its Al-modified derivatives, CrFeMoV-Al2 and CrFeMoV-Al6, which belong to the family of high- and medium-entropy alloys. The studied systems were produced via Vacuum Arc Melting (VAM), followed by a comprehensive characterization. Thermodynamic and geometric phase-formation models were employed to predict the formation of BCC/Β2 solid solutions and the potential emergence of σ-type intermetallic compounds. An ML model was also employed to further predict elemental interactions and phase evolution. These predictions were experimentally confirmed via X-ray diffraction analysis, which verified the presence of a BCC matrix in all compositions, the presence of σ-phase precipitates whose volume fraction systematically reduced with Al inclusion and the gradual increase in the B2 phase with the increase in the Al content. Scanning electron microscopy and EDX analyses uncovered noticeable dendritic segregation, with Mo and Fe enrichment in dendrite cores and in interdendritic regions, respectively. Cr, V, and Al were more uniformly distributed. Mechanical property data derived by micro hardness testing demonstrated a high hardness of 816 HV for the base alloy, ascribed to σ-phase strengthening, followed by a progressive reduction in this value to 802 HV and 756 HV in Al-containing alloys due to the attenuation of σ-phase formation and the gradual increase in the B2 phase. Dry sliding wear results unveiled a positive correlation between wear resistance and hardness, confirming the beneficial role of intermetallic strengthening. Finally, nanoindentation tests shed light on the nanoscale mechanical response, confirming the trends observed at the microscale. Overall, the combination of thermodynamic modeling and experimental analysis provide a robust framework for understanding phase stability, microstructural evolution, and mechanical performance in Al-alloyed CrFeMoV high-entropy systems, while highlighting the potential of controlled Al additions to tailor microstructure and properties. Full article

A large, low-grade Fe–Ti–V oxide deposit occurs within the Xiaohaizi Ultramafic–Mafic intrusion. Based on petrographic observations and electron probe microanalysis (EPMA) of amphibole, this study examines the magmatic evolution and ore-forming processes of the intrusion through analyses of amphibole occurrence, mineral chemistry, and crystallization conditions. Five textural types of amphibole were identified: (i) inclusions, (ii) co-crystallization with early silicates, (iii) reaction rims, (iv) co-crystallization with late Fe–Ti oxides, and (v) phenocrysts. The amphiboles are calcic varieties, mainly composed of magnesio-hastingsite, kaersutite, and tschermakite. Crystallization occurred at temperatures of 901–1013 °C and pressures of 254–424 MPa, with ΔNNO values ranging from −1.3 to +2.8 and estimated melt H₂O contents of 3.3–7.1 wt.%, corresponding to crystallization depths of 9.6–16.0 km. Importantly, the crystallization interval of the Fe–Ti oxides is defined by these amphibole-assemblage conditions, as evidenced by their direct intergrowth. Integration of mineralogical and geochemical data indicates that the Xiaohaizi intrusion underwent four distinct stages of magmatic evolution. During these stages, the crystallization of Fe–Ti oxides was accompanied by notable fluctuations in oxygen fugacity and melt water content. These results suggest that fractional crystallization played a dominant role in ore formation, with possible late-stage liquid immiscibility observed at the mineral scale. Overall, this study proposes that the Xiaohaizi Fe–Ti–V oxide deposit represents a magmatic conduit-type ore-forming system developed within a crystal mush. The enrichment of Fe–Ti oxides is strongly associated with hydrous melts and elevated oxygen fugacity conditions. Full article

The morphology and types of inclusion, as well as the microstructure, fundamentally affect the properties of high-strength peritectic steel. Rare earth elements not only modify inclusions but also act on the transformation of the microstructure. In this paper, the evolution mechanism of yttrium for the inclusions and microstructure in high-strength peritectic steel was investigated through experimental testing and thermodynamic analysis. The results show that yttrium treatment can modify the main large-sized irregular inclusions into spherical or near-spherical rare earth inclusions, accompanied by a reduction in the number density, area fraction, average diameter, and aspect ratio of inclusions. The evolution route for the inclusions follows Al₂O₃ + MnS + Al₂O₃-MnS→Y₂O₃ + Y-O-S + Y-S + Y-O-S-MnS with yttrium addition. The microstructural characteristics of yttrium-free steel show significant differences from those of yttrium-containing steel. Compared to yttrium-free steel, the yttrium-0.015 wt.% steel shows a refined austenite structure with more uniform size distribution and the absence of grain boundary ferrite films. The Y₂O₃ and Y₂O₂S inclusions mainly formed in liquid steel were found along the austenite grain boundary to prevent the grain growth and the formation of ferrite films. Additionally, after adding rare earth yttrium, the fraction of high-angle grain boundaries (HAGBs) increases, together with a decrease in the fraction of low-angle grain boundaries (LAGBs) in steel. The research results can provide a theoretical basis for the application of adding rare earth yttrium to high-strength peritectic steel. Full article

Background: Acute myocarditis is defined as an inflammatory process consisting of multiple complex physiopathological processes. Due to its variability, the management of this condition has been a topic of debate. Our study aimed to evaluate the efficacy and safety of intravenous immunoglobulin (IVIg). Methods: We retrospectively collected data from patients admitted to a paediatric cardiology department from 2015 to 2020. Following the inclusion and exclusion criteria, a total of 68 patients diagnosed with acute myocarditis were selected and divided into two groups: treated with IVIg and untreated. We determined clinical and paraclinical parameters, such as symptom remission, normalisation of the ejection fraction at discharge, and cardiac marker evolution. Mixed-design analysis of variance and McNemar tests were performed to determine the statistical differences between groups. Results: In the treated group, 88.2% of the patients developed symptom remission at discharge vs. 50% in the untreated group, and 61.8% of the treated patients presented normalisation of the ejection fraction (EF) vs. 8.8% in the untreated group (p < 0.05). The evolution of cardiac markers did not statistically differ between the treated and untreated groups. Regarding safety, three treated patients presented mild, temporary side effects. Conclusions: Having found a statistically significant improvement in symptomatology and left ventricular EF, our study suggests the efficacy of IVIg in the treatment of acute myocarditis. Treatment with immunoglobulins was relatively safe, with only mild adverse reactions (fever and mild chest pain). Full article

Coalbed methane (CBM) development involves multiple interacting physical fields, and different coupling schemes can lead to distinctly different production behaviors. A thermo-hydro-mechanical model accounting for gas–water two-phase flow and matrix dynamic diffusion (TP-D-THM) is developed and validated, achieving an error rate below 10%. By embedding the numerically estimated reservoir physical parameters of the Qinshui Basin into the numerical model, multi-field couplings during CBM production, the evolution of physical parameters, and the depth-dependent effects on production characteristics were revealed. The main findings are as follows: The inhibitory effect of water on CBM recovery consistently exceeds the promoting effect of temperature. As burial depth expands, the inhibitory effect first diminishes, then intensifies, ranging from 19.73% to 28.41%, while the thermal promotion effect exhibits a monotonically increasing trend, fluctuating between 8.55% and 16.33% and stabilizing below 1000 m. Temperature and burial depth do not alter the trend in gas production rate. For equilibrium permeability, reproducing a decrease–increase–decrease rate pattern requires explicit inclusion of water and matrix-fracture mass exchange terms, which can explain why different scholars obtained varying gas production rate trends using the THM model. Matrix adsorption-induced strain is the primary control on permeability evolution, and temperature amplifies the magnitude of permeability change. The critical depth essentially reflects the statistical characteristics of reservoir petrophysical properties. A dimensionless critical depth criterion has been proposed, which comprehensively considers reservoir pressure, permeability, and a fractional coverage index. For burial depths ranging from 650 to 1350 m, the TP-D-THM model can be simplified to the gas-mechanical model accounts for matrix dynamic diffusion (D-HM) with an error below 5%, indicating that thermal and water effects nearly cancel each other. Full article

The Paleozoic strata in the Kongxi slope zone of the Dagang oilfield, Huanghua depression, exhibit significant hydrocarbon exploration potential. Although bitumen is widely present in the Paleozoic reservoirs, its formation process and genetic mechanism remain poorly understood. This study systematically investigates the occurrence, maturity, origin, and evolutionary processes of Paleozoic reservoir bitumen in the Kongxi zone through core observations, microscopic analyses, geochemical testing, and thermal simulation experiments. The results reveal that reservoir bitumen in the Kongxi slope zone is characteristically black with medium to medium-high maturity. In core samples, bitumen occurs as bands, veins, lines, and dispersions within partially filled fractures and breccia pores. Petrographic analysis shows bitumen partially occupying intergranular pores and intergranular pores of Lower Paleozoic carbonate rocks and Upper Paleozoic sandstones, either as complete or partial pore fills. Additional bitumen occurrences include strip-like deposits along microfractures and as bitumen inclusions. Dark brown bitumen fractions were also identified in crude oil separates. The formation and evolution of Paleozoic reservoir bitumen in the Kongxi slope zone occurred in two main stages. The first-stage bitumen originated from Ordovician marine hydrocarbon source rocks, subsequently undergoing oxidative water washing and biodegradation during tectonic uplift stage. This bitumen retains compositional affinity with crude oils from Lower Paleozoic carbonate rocks. Second-stage bitumen formed through the thermal evolution of Carboniferous crude oil during deeper burial, showing compositional similarities with Carboniferous source rocks and their oil. This two-stage bitumen evolution indicates charging events in the Paleozoic reservoirs. While early uplift and exposure destroyed some paleo-reservoirs, unexposed areas within the Dagang oilfield may still contain preserved primary accumulations. Furthermore, second-stage hydrocarbon, dominated condensates derived from Carboniferous coal-bearing sequences since the Eocene, experienced limited thermal evolution to form some bitumen. These condensate accumulations remain the primary exploration target in the Paleozoic Formations. Full article

In this paper, we mainly focus on the the existence of Hilfer fractional evolution inclusions with almost sectorial operators. For two cases in which the almost sector operators are compact and noncompact, we obtain existence criteria for mild solutions, which extend and improve some related results in the literature. Full article

To understand the fluid evolution of Permian pegmatites, three pegmatite fields of the Austroalpine basement units located in the Rappold Complex at St. Radegund, the Millstatt Complex, and the Polinik Complex were investigated. To achieve this goal, fluid inclusions trapped in the magmatic accessories of garnet, tourmaline, spodumene, and beryl were studied using host mineral chemistry combined with fluid inclusion microthermometry and Raman spectrometry. Taking into account the previous work by the authors on pegmatite fields in the Koralpe and Texel Mountains, Permian fluid was determined to have evolved from two stages: Stage 1 is characterized by the homogeneous entrapment of two cogenetic immiscible fluid assemblages, a CO₂-N₂ ± CH₄-rich and a low-saline H₂O-rich fluid. Both fluids are restricted to inclusions in the early-magmatic-garnet-core domains of the Koralpe Mountains. Stage 2 is linked with the CO₂-N₂-CH₄-H₂O-NaCl-CaCl₂ ± MgCl₂ fluid preserved as an inclusion in all the pegmatite accessories of the KWNS. It represents the mechanical mixture of the stage 1 fluid caused by compositional changes along the solvus, which is typical for a hydrothermal vein environment process. Increasing X_CH4±N2 proportions from the eastern toward the western pegmatite fields of the KWNS results in a tectonic model that includes magmatic redox-controlled fluid flow along deep crustal normal faults during the anatexis of metasediments in Permian asymmetric graben structures. Because of a high number of solids within the inclusions as well as their irregular shapes, post-entrapment modifications have caused density changes that have to be considered with caution. However, the conditions in the range of 6–8 kbar at >670 °C for stage 1 and ca. 4 kbar at <670 °C for stage 2 represent the best approximations to explain the uprise of a two-stage Permian fluid associated with accessory mineral crystallization in close relation to fractionating melt. Full article

With the increasingly demanding service conditions of coiled tubing, its welded joints require superior synergistic strength-toughness properties to meet comprehensive mechanical performance requirements. This study achieved synergistic optimization of strength and toughness in deposited metal via lanthanum microalloying technology and elucidated microstructural evolution mechanisms and fracture failure mechanisms via multi-scale characterization techniques. The results demonstrate that lanthanum oxide addition effectively modifies inclusion characteristics, inducing phase transformation from O-Mn-Si-Al-Ti to O-Mn-Si-Al-Ti-S-La, with average particle size significantly decreased from 0.19 μm to 0.12 μm. The deposited metal microstructure comprises lath bainite and granular bainite. The addition of 0.5 wt.% lanthanum oxide results in significant microstructural refinement: average grain size decreases from 1.16 ± 1.18 μm to 1.02 ± 1.00 μm, while granular bainite volume fraction decreases from 8.6% to 4.7%. The microstructural optimization also enhances mechanical properties substantially: yield strength increases from 628 ± 14 MPa to 673 ± 12 MPa, and impact toughness improves from 160 ± 6 J to 189 ± 6 J. Mechanistic analysis revealed that proper addition of lanthanum (0.5 wt.%) promotes grain refinement via heterogeneous nucleation and modifies inclusion morphology, effectively inhibiting crack initiation. However, excessive addition (1.0 wt.%) induces inclusion clustering, forming stress concentration sites that degrade mechanical properties. Full article

The production of silicon steel involves complex metallurgical processes, where the kind, composition, size, and quantity of the inclusions generated affect the silicon steel properties. This article is based on the smelting process for W350 non-oriented silicon steel produced by a certain factory. By systematically sampling, at key nodes of the converter–RH refining–tundish smelting process, the change in cleanliness of molten steel in the whole smelting process, the evolution of typical inclusions, and the transformation rules for the precipitated phase were analyzed by means of SEM-EDS, ASPEX, and Thermal-Calc. The results indicate that the total oxygen mass fraction in the steel decreases by more than 95% after deoxidation alloying, and the average oxygen mass fraction in the RH outbound steel is 0.0012%. While the nitrogen mass fraction shows a rising trend as a whole, the average nitrogen mass fraction in the tundish steel reaches approximately 0.0014%. Before RH refining, large Al₂O₃–CaO–SiO₂ and Al₂O₃–CaO–SiO₂–MgO composite inclusions are the main inclusions. MnO and Al₂O₃–SiO₂–MnO inclusions are the main inclusions after RH inlet and RH decarburization. After RH deoxidation with aluminum, the inclusions were almost entirely transformed into Al₂O₃ inclusions. After RH alloying, with the content of Si and Mn increased, the inclusions transformed into Al₂O₃–SiO₂–MnO inclusions. The number of inclusions from RH desulfurization to the RH outbound stage declined significantly, and composite inclusions containing CaS and precipitates such as AlN and MnS began to appear. The inclusions’ main types were Al₂O₃–MgO–CaS, AlN–MnS, AlN, and Al₂O₃–MgO. The inclusions inside the tundish were the same, but the numbers were slightly increased due to the secondary oxidation of molten steel. More than 80% of the oxide inclusions in the whole process were between 1 μm and 5 μm in size. The average size and the number of inclusions per unit area reached 5.45 μm and 63.1 per mm², respectively, after RH deoxidation, and respectively decreased to 3.71 μm and 1.9 per mm² during the RH outbound stage, but both increased slightly in the tundish. Thermodynamic calculation shows that Al₂O₃–MgO inclusions are formed when w([Mg]) > 0.0033% in molten steel at 1873 K. Under the actual temperature of 1828K and w([Al]s) = 0.6515%, the range of w([Mg]) corresponding to the stable existence of Al₂O₃–MgO is between 0.0053% and 0.1676%. The liquidus temperature of W350 non-oriented silicon steel is 1489 °C. MnS and AlN inclusions are precipitated successively with the solidification of molten steel, and the precipitation temperatures are 1460.7 °C and 1422.2 °C, respectively. As the temperature decreases, the sequence of inclusion precipitation calculated in liquid was as follows: Al₂O₃–CaO → 2Al₂O₃–CaO + MnS → 6Al₂O₃–CaO → Al₂O₃ + AlN + MnS + CaS. Full article

This paper addresses the approximate controllability results for Hilfer fractional stochastic differential inclusions of order $1<\mathsf{q}<2$. Stochastic analysis, cosine families, fixed point theory, and fractional calculus provide the foundation of the main results. First, we explored the prospects of finding mild solutions for the Hilfer fractional stochastic differential equation. Subsequently, we determined that the specified system is approximately controllable. Finally, an example displays the theoretical application of the results. Full article

Introduction: The aim of this study was to evaluate the age at onset, clinical course, and patterns of left ventricular (LV) remodelling during follow-up in children and young patients with hypertrophic cardiomyopathy (HCM). Methods: We included consecutive patients with sarcomeric or non-syndromic HCM below 18 years old. Three pre-specified patterns of LV remodelling were assessed: maximal LV wall thickness (MLVWT) thickening; MLVWT thinning with preserved LV ejection fraction; and MLVWT thinning with progressive reduction in LV ejection fraction (hypokinetic end-stage evolution). Results: Fifty-three patients with sarcomeric/non-syndromic HCM (mean age 9.4 ± 5.5 years, 68% male) fulfilled the inclusion criteria. In total, 32 patients (60%) showed LV remodelling: 3 patients (6%) exhibited MLVWT thinning; 16 patients (30%) showed MLVWT thickening; and 13 patients (24%) progressed to hypokinetic end-stage HCM. Twenty-one patients (40%) had no LV remodelling during follow-up. In multivariate analysis, MLVWT was a predictor of the hypokinetic end-stage remodelling pattern during follow-up (OR 1.17 [95%CI 1.01–1.36] per 1 mm increase, p-value 0.043), regardless of sarcomeric variants and New York Heart Association class. Two patients with sarcomeric HCM, showing a pattern of MLVWT regression during childhood, experienced progression during adolescence. Conclusions: Different patterns of LV remodelling were observed in a cohort of children with sarcomeric/non-syndromic HCM. Interestingly, a pattern of progressive MLVWT thinning during childhood, with new progression of MLVWT during adolescence, was noted. A better understanding of the remodelling mechanisms in children with sarcomeric HCM may be relevant to defining the timing and possible efficacy of new targeted therapies in the preclinical stage of the disease. Full article

This paper deals with the research of solutions of bounded variation (BV) to evolution inclusion coupled with a time and state dependent maximal monotone operator. Different problems are studied: existence of solutions, unicity of the solution, existence of periodic and bounded variation right continuous (BVRC) solutions. Second-order evolution inclusions and fractional (Caputo and Riemann–Liouville) differential inclusions are also considered. A result of the Skorohod problem driven by a time- and space-dependent operator under rough signal and a Volterra integral perturbation in the BRC setting is given. The paper finishes with some results for fractional differential inclusions under rough signals and Young integrals. Many of the given results are novel. Full article