Search Results (2,771)

This study compares the chemical profiles of pomegranate seed oil (PSO) from two cultivars, Granato (G) and Roce (R), extracted by Soxhlet and supercritical CO₂/isopropanol. GC-MS and NMR analyses confirmed punicic acid as the dominant fatty acid, with α-eleostearic, oleic, and linoleic acids in lower amounts. Supercritical extraction increased yield (about 18%) and selectively raised α-eleostearic and linoleic acids. Volatile organic compound (VOC) profiling by HS-SPME-GC-MS showed higher aldehydes, esters, and terpenes in supercritical extracts, including (E)-cinnamaldehyde (absent in Soxhlet). Soxhlet oils contained more hydrocarbons, suggesting thermal degradation. Overall, supercritical CO₂/IPA proved more sustainable and selective, preserving nutritional and aromatic quality and supporting PSO’s potential in food, nutraceutical, and cosmetic uses. Full article

The Huangliu Formation, Section I, Gas Group II, at the eastern X gas field of the Yinggehai Basin, hosts thick, irregularly deposited sandstone bodies. The genesis of these sedimentary sand bodies has remained unclear. Utilizing drilling logs, core samples, and 3D seismic data from this field, this study integrates seismic geomorphology analysis, paleo-hydrodynamic reconstruction, and sedimentary numerical simulation to investigate the spatiotemporal evolution of the depositional system under micro-paleotopographic conditions during Gas Zone II sedimentation. Key conclusions include the development of seven morphologically diverse isolated sand bodies in the Lower II Gas Zone, covering areas of 1.4–13.4 km² with thicknesses ranging from 8.0 to 42.0 m. These sand bodies consist predominantly of massive fine-grained sandstone, characterized by box-shaped gamma-ray (GR) log responses and U- or V-shaped seismic reflection configurations. Reconstruction of paleo-turbidity current hydrodynamics for the Lower II depositional period was achieved through analysis of topographic slope gradients and the dimensional constraints (width/depth) of confined channels. Critically, slope gradients within the intraslope basin prompted a transition from supercritical to subcritical flow states within turbidity currents. This hydraulic transformation drove alternating erosion and deposition along the seafloor topography, ultimately generating the observed irregular, isolated turbidite sand bodies. Full article

The emergence of bacterial strains resistant to available antibiotics due to overprescription has prompted a search for alternative treatments. Among the most promising is baicalin, a flavonoid extracted from the roots of Scutellaria baicalensis. Roots, the primary natural source of baicalin, have been extensively explored using emerging extraction technologies such as ultrasonic-assisted extraction and supercritical fluid extraction. These methods offer significant advantages over traditional reflux extraction for baicalin preparation, including shorter extraction times, lower energy consumption, and improved environmental sustainability. Baicalin exhibits remarkable antibacterial activity in vitro and has demonstrated therapeutic efficacy against gastrointestinal infections, meningitis, pulmonary diseases, and sepsis, among other infectious disorders, in animal models. Documented mechanisms of action include disrupting the Escherichia coli membrane, downregulating quorum-sensing gene expression in Pseudomonas aeruginosa, and inhibiting host inflammatory pathways such as PI3K/Akt/NF-κB. However, its clinical translation faces several bottlenecks, including reliance on animal experiment data, low bioavailability, and regulatory compliance issues. This review compares baicalin extraction yields from different natural sources, summarizes the advantages and disadvantages of various extraction technologies, analyzes possible mechanisms of action in treating different bacterial diseases, and discusses outstanding challenges and best strategies for expanded clinical use against bacterial infection. Our aim is to provide a valuable reference for future research and clinical applications. Full article

Apigenin (AP) is a natural flavonoid with senomorphic potential and neuroprotective action; however, poor aqueous solubility (<1 μg/mL) limits its bioavailability and therapeutic use. Therefore, the aim of this study was to obtain an amorphous dispersion of AP and evaluate its biological properties. Screening of AP solubilization capabilities under supercritical carbon dioxide processing conditions showed that the system with Soluplus (SOL) achieved the greatest improvement in AP dissolution (6455.4 ± 27.2 μg/mL). Using optimized process parameters (50 °C, 6500 PSI), the AP solubility increased to 8050.2 ± 35.1 μg/mL. X-ray powder diffraction (XRPD) confirmed amorphization, aligning with improved dissolution of AP in both acidic and neutral pH media. As a result, using the PAMPA model, an improvement in AP penetration through membranes simulating gastrointestinal and blood–brain barriers was demonstrated. The significant stability of the obtained amorphous AP dispersion (12 months at room conditions) was associated with stabilizing AP–solubilizer intermolecular interactions, mainly expressed as the shifts in the bands of AP in the range of 1018–1269 cm⁻¹ observed in ATR-FT-IR spectra. Chromatographic analysis confirmed the lack of AP decomposition immediately after the preparation of the amorphous dispersion, as well as after 12 months. As expected, the improvement of AP solubility is correlated with better biological activity assessed in selected in vitro tests such as antioxidant properties (2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and cupric ion reducing antioxidant capacity (CUPRAC) assays) and anticholinesterase inhibition capabilities (AChE and BChE assays). The effect of the studies on improving AP solubility under supercritical carbon dioxide processing conditions is obtaining a stable amorphous AP dispersion (up to 12 months). Regardless of the pH of the media, an improvement in AP dissolution and penetration, conditioned by the passive diffusion process, through biological membranes was noted. Moreover, a more efficient antioxidant and neuroprotective effect of AP in the developed amorphous dispersion can also be suggested. Full article

Fruit pomace, generated as a by-product of juice processing, is a valuable source of bioactive compounds but requires sustainable extraction approaches to enable its valorisation. Supercritical CO₂ extraction (SFE-CO₂) represents a promising green technology due to its efficiency, solvent-free character, and tuneable selectivity. In this study, the response surface methodology (RSM) was applied to evaluate the effects of pressure, temperature, and time on the recovery of fat, protein, and total phenolic compounds (TPCs) from blackcurrant (Ribes nigrum) and redcurrant (Ribes rubrum) pomace subjected to conventional- and freeze-drying. The highest protein content (14.5%) was obtained in freeze-dried blackcurrant at 400 bar, 60 min, and 30 °C, while the maximum TPCs (24.60 mg GAE/g d.w.) was reached at 500 bar, 60 min, and 40 °C. The redcurrant samples consistently showed lower extractable values across all the responses. Pressure and time were identified as the most influential process variables, enhancing the solvent density and mass transfer during extraction. These results demonstrate that both the drying pre-treatment and raw material type significantly affect the SFE efficiency and confirm the potential of optimised SFE-CO₂ as a viable strategy for converting fruit pomace into functional ingredients for food, nutraceutical, and cosmetic applications. Full article

Clarifying the phase evolution history of hydrocarbon fluids helps formulate exploration and development strategies. The discovery of the Xinguang Gas Field marks a significant breakthrough in the Western Junggar Basin. However, the phase evolution history of this gas field remains unclear, which hinders the formulation of subsequent exploration strategies. This study employs a comprehensive approach, combining organic geochemistry, fluid inclusions, basin modeling, and PVT testing and simulation, to investigate the characteristics and phase behavior of deep-seated hydrocarbon fluids in this gas field. It also examines the charging history, compositional evolution, and temperature and pressure histories of the reservoir, thereby clarifying the phase transition process of hydrocarbon fluids in the Xinguang Gas Field. This study finds that the deep-seated reservoir fluids in the Jiamuhe Formation (Fm.) of the Xinguang Gas Field exhibit low densities of 0.77 to 0.83 g/cm³, high gas-to-oil ratios (GORs) of 1014.41 to 13,054.77 m³/m³, high methane contents of 91.16% to 92.74%, and retrograde condensation characteristics. Additionally, the reservoir temperature and pressure exceed the critical point and the saturation pressure at reservoir temperature, indicating a supercritical condensate gas phase. The present condensate gas in the Xinguang Gas Field is a mixed hydrocarbon from two charging events. Initially, during the Middle–Late Triassic period, both Block 1 and the Xinguang Gas Field were charged with mature oil. Later, from the Late Cretaceous to Early Neogene periods, a secondary charging of highly mature oil and gas occurred in the Xinguang Gas Field, while the reservoir in Block 1 remained largely unchanged. In the co-evolution of reservoir fluid composition, temperature, and pressure, the phase transitions of the hydrocarbon fluids in the Xinguang Gas Field passed through several stages, including liquid black oil (231.9–80.3 Ma), liquid volatile oil (80.3–79.1 Ma), vapor–liquid two-phase volatile oil (79.1–78.3 Ma), vapor–liquid two-phase condensate gas (78.3–69.1 Ma), and supercritical condensate gas (69.1 Ma–present). Full article

The article discusses the current challenges facing the energy sector in the context of climate policy, technological transformation, and the urgent need to increase energy efficiency while reducing greenhouse gas emissions. Modern thermal energy conversion technologies are analyzed, including supercritical steam and gas–steam cycles, as well as distributed systems using renewable fuels and microturbines. Particular attention is given to innovative systems with isothermal expansion, which theoretically allow operation close to the efficiency limit defined by the Carnot cycle. The study presents calculation results for conventional systems (steam, gas with regeneration, and Organic Rankine Cycle) and proposes a novel isothermal air turbine cycle. In a combined gas–steam configuration, the proposed cycle achieved an efficiency exceeding 43% at a relatively low heat source temperature of 700 K, clearly outperforming conventional steam and ORC systems under the same thermal conditions. The use of a simple working medium (air), combined with the potential for integration with renewable energy sources, makes this concept a promising and viable alternative to traditional Rankine and Brayton cycles in thermally constrained applications. Full article

Gas coolers play a critical role in CO₂ refrigeration and heat pump systems, where their thermohydraulic characteristics substantially influence the overall system performance. To improve the heat transfer performance of gas coolers, minichannels with aligned or offset fins integrated in the channel sidewalls are proposed to enlarge the heat transfer surface and intensify the flow turbulence. Unlike conventional refrigerants, supercritical CO₂ exhibits significant variations in thermophysical properties with temperature changes, which results in distinct heat transfer behavior. Three-dimensional numerical models are therefore purposely developed by employing the Shear Stress Transport k-ω turbulent model and including the entrance region effect, NIST real-gas thermophysical properties and buoyancy effect. A constant heat flux boundary is employed on the four-side channel walls to ensure that the temperature of CO₂ flowing in the channel exactly decreases from 373.15 K to 308.15 K. The results show that the fins integrated in the channel sidewalls can significantly improve the heat transfer performance, and the heat transfer coefficient significantly increases with increasing mass flux. Compared to the reference smooth channel, the heat transfer performance is enhanced by a factor of 1.85–2.15 with aligned fins and 1.44–1.61 with offset fins. Full article

The novel engines nowadays with high efficiency are operated under the superpressure, supercritical, and supersonic extreme conditions that are situated in the broken reaction zone regime. In this article, the propagation and heat/radical diffusion physics of a high-pressure dimethyl ether (DME)/air turbulent lean-premixed flame are investigated numerically by direct numerical simulation (DNS). A wide range of statistical and diagnostic methods, including Lagrangian fluid tracking, Joint Probability Density Distribution (JPDF), and chemical explosive mode analysis (CEMA), are applied to reveal the local combustion modes and dynamics evolution, as well as the roles of heat/mass transport and cool/hot flame interaction in the turbulent combustion, which would be beneficial to the design of novel engines with high performances. It is found that the three-staged combustion, including cool-flame, warm-flame, and hot-flame fronts, is a unique behavior of DME flame under the elevated-pressure, lean-premixed condition. In the broken reaction zone regime, the reaction zone thickness increases remarkably, and the heat release rate (HRR) and fuel consumption rate in the cool-flame zone are increased by 16% and 19%, respectively. The diffusion effect not only enhances flame propagation, but also suppresses the local HRR or fuel consumption. The strong turbulence interplaying with diffusive transports is the underlying physics for the enhancements in cool- and hot-flame fronts. The dominating diffusive sub-processes are revealed by the aid of the diffusion index. Full article

This study introduces a novel, two-stage extraction system that combines Ohmic-Accelerated Steam Distillation (OASD) with Supercritical CO₂ Extraction (SSCO₂) to efficiently recover bioactive compounds from plant-based wastes with varying cell wall complexities. Brewer’s spent grain (BSG) and cocoa shell were selected as representative models for soft and rigid cell wall structures, respectively. The optimized extraction process demonstrated significantly enhanced efficiency compared to traditional methods, achieving recovery rates in BSG of 89% for antioxidants, 91% for phenolic acids, and 90% for polyphenolic compounds. Notably, high yields of p-coumaric acid (95%), gallic acid (94%), ferulic acid (82%), quercetin (87%), and resveratrol (82%) were obtained with minimal cellular structural damage. For cocoa shells, despite their lignin-rich, rigid cell walls, recovery rates reached 73% for antioxidants, 79% for phenolic acids, and 74% for polyphenolic compounds, including chlorogenic acid (94%), catechin (83%), vanillin (81%), and gallic acid (94%). Overall, this hybrid technique significantly improved extraction efficiency by approximately 60% for BSG and 50% for cocoa shell relative to conventional approaches, highlighting its novelty, scalability, and potential for broad application in the sustainable valorization of diverse plant-based waste streams. This research presents a green and efficient platform suitable for valorizing agri-food by-products, supporting circular economy goals. Further studies may explore scale-up strategies and economic feasibility for industrial adoption. Full article

CO₂ geological storage (CGS) is critical for mitigating emissions in hard-to-abate industries under carbon neutrality. However, its implementation faces significant challenges. This paper examines CO₂-trapping mechanisms and proposes key safety measures: the continuous monitoring of in situ CO₂ migration and formation pressure dynamics to prevent remobilization, and pre-injection lithological analysis to assess mineral trapping potential. CO₂ injection alters reservoir stresses, inducing surface deformation; understanding long-term rock mechanics (creep, damage) is paramount. Thermomechanical effects from supercritical CO₂ injection pose risks to caprock integrity and fault reactivation, necessitating comprehensive, multi-scale, real-time monitoring for leakage detection. Geostatistical analysis of well log and seismic data enables realistic subsurface characterization, improving numerical model accuracy for risk assessment. This review synthesizes current CGS knowledge, analyzes technical challenges, and aims to inform future site selection, operations, and monitoring strategies. Full article

Carbon dioxide capture, utilization, and storage for enhanced oil recovery (CCUS-EOR) represents an effective strategy for reducing CO₂ emissions while improving oil recovery efficiency. However, harsh environmental conditions during the process can induce a supercritical state in captured CO₂, which may undermine the structural integrity of tubular components through corrosion. This study systematically investigated the corrosion behaviors of two tubing steels (P110 and Super 13Cr) in 20 MPa supercritical CO₂ containing trace H₂S/O₂ impurities at 60–120 °C using weight loss tests and surface analysis. The results demonstrate that in water-unsaturated supercritical CO₂ with ≤500 ppmv H₂S, both steels exhibited low general corrosion rates (P110: 0.03 mm/y; S13Cr: 0.01 mm/y), with incomplete surface films partially covering grinding traces. However, S13Cr suffered pitting corrosion at >500 ppmv H₂S. Oxygen introduction triggered severe general/localized corrosion characterized by cracked, non-protective surface films. Reducing O₂ to 500 ppm yielded thin, continuous protective films, eliminating pitting. Temperature critically influenced S13Cr corrosion: decreasing from 120 °C to 60 °C increased the corrosion rates from 0.0031 mm/y to 0.08 mm/y due to enhanced water precipitation and impurity gas dissolution. These findings establish impurity thresholds to ensure acceptable corrosion performance. Full article

Supercritical carbon dioxide (Sc-CO₂) thermal shock fracturing emerges as an innovative rock fragmentation technology combining environmental sustainability with operational efficiency. This study establishes a thermo-hydro-mechanical coupled model to elucidate how in situ stress magnitude and anisotropy critically govern damage progression and fluid dynamics during Sc-CO₂ thermal shock fracturing. Key novel findings reveal the following: (1) The fracturing mechanism integrates transient hydrodynamic shock with quasi-static pressure loading, generating characteristic bimodal pressure curves where secondary peak amplification specifically indicates inhibited interwell fracture coalescence under anisotropic stress configurations. (2) Fracture paths undergo spatiotemporal reorientation—initial propagation aligns with in situ stress orientation, while subsequent growth follows thermal shock-induced principal stress trajectories. (3) Stress heterogeneity modulates fracture network complexity through confinement effects: elevated normal stresses perpendicular to fracture planes reduce pressure gradients (compared to isotropic conditions) and delay crack initiation, yet sustain higher pressure plateaus by constraining fracture connectivity despite fluid leakage. Numerical simulations systematically demonstrate that stress anisotropy plays a dual role—enhancing peak pressures while limiting fracture network development. This demonstrates the dual roles of the technology in enhancing environmental sustainability through waterless operations and reducing carbon footprint. Full article

Light-emitting diodes (LEDs) are made up of precious metals, e.g., gallium. These elements can be recovered and reused, reducing the need for new raw materials. Proper recycling prevents harmful substances in LEDs, such as lead and arsenic, from contaminating the environment. Recycling LEDs uses less energy compared to producing new ones, leading to lower carbon emissions. The valuable metal gallium faces the challenge of supply and demand due to the surge in its demand, the difficulty of separating it from minerals, and processing issues during extraction. In this review, we describe the methods for recycling gallium from LEDs by using different techniques such as pyrolysis (95% recovery), oxalic acid leaching (83.2% recovery), HCL acid leaching of coal fly ash (90–95% recovery), subcritical water treatment (80.5% recovery), supercritical ethanol (93.10% recovery), oxidation and subsequent leaching (91.4% recovery), and vacuum metallurgy separation (90% recovery). Based on our analysis, hydrometallurgy is the best approach for recovering gallium. It is reported that approximately 5% of the waste from LEDs is adequately recycled, whereas the total gallium potential wasted throughout production is over 93%. By recycling LEDs, we can minimize waste, conserve resources, and promote sustainable practices. Thus, recycling LEDs is essential for strengthening a circular economy. Full article

Tight oil reservoirs are characterized by low porosity, low permeability, and low saturation, making it difficult to achieve economic development through conventional water injection. This study experimentally evaluated different injection media and oil displacement methods and used nuclear magnetic resonance methods to explain the micro mechanisms of oil displacement during different oil displacement processes. The experiments showed that supercritical CO₂ flooding and supercritical CO₂ and active water alternating flooding were much more useful for low-permeability reservoirs compared with conventional water flooding. This technology can increase the recovery rate by more than 12.0%, which is 33.24% higher than the rate achieved with conventional water injection. In addition, it can effectively improve the rapid increase in water content caused by the rapid advance in the water front during the water injection process. The NMR results indicated good consistency for the recovery efficiency of pores under different oil displacement conditions. When the aperture varied between 0.1 µm and 1 µm (type III), the utilization rate was highest, followed by type IV (1–10 µm), type II (0.01–0.1 µm), and type I (0.001–0.01 µm). By comparison, conventional water and CO₂ alternating flooding was more effective for type III pores, increasing oil recovery by 12.58%, while active water + CO₂ alternating flooding can further drive oil, increasing oil recovery by 33.24% and greatly displacing oil in micro-pores and macro-pores. Full article