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Long a thermodynamic curiosity, supercritical fluids (SCFs) have gradually gained ground in today's life, generating an increasing number of new, efficient processes in diverse industrial sectors and fueling active R&D programs. Indeed, the versatility of SCFs allows them to serve a wide variety of applications. The list includes not only food processing, biofuel production, extraction of biomolecules marketable as medicines, cosmetics and nutraceuticals, but also emerging technologies for the production of electrical power, based on supercritical or transcritical thermodynamic cycles. This jointly authored article will provide a review of important applications covered by our laboratories in the agri-food, chemical and energy sectors. We will then try to detect recent trends and outline future prospects. [ABSTRACT FROM AUTHOR]

The effect of the initial atoms distribution on the molecular dynamics (MD) simulation of a model atomic fluid (argon) is investigated for the case of the isochoric phase transition to the supercritical state. In particular, the case of uniformly distributed atoms in the simulation domain is compared with the case of separated liquid and vapor atoms. The sensitivity of simulations to asymmetric nanoscale perturbations in the boundary is also studied. Despite its high computational cost, the MD approach has the potential to successfully address long‐standing problems in computational fluid dynamics (CFD), especially those associated with mathematical singularities, such as contact angles, vortices, phase transitions and so forth. Unlike conventional CFD simulations, where the initial condition is the pressure or velocity distribution in the simulation domain, MD simulations also require the initial position of each molecule. Thus, it is important to understand whether a judicious choice of the initial distribution of molecules can reduce the overall computation time of the simulation. The evolution of the model fluid system during the phase transition was simulated using a Lennard‐Jones interatomic potential, corrected with the Lorentz–Berthelot mixing rule for the interactions with the solid walls. The system was allowed to relax until equilibrium, and then a Heaviside temperature step was applied to the wall to bring the system to supercritical conditions. Results show the initial choice of the atoms distribution can significantly affect the computational time, while the effect of asymmetric perturbations on the boundary is negligible. [ABSTRACT FROM AUTHOR]

This paper focuses on the research progress related to the thickening mechanism of carbon diox・ ide. And the four mechanisms of thickening carbon dioxide are summarized・ The basic theory of supercritical C02 viscidity increase is similar solubilization mechanism・ Entropy increase and enthalpy decrease is an important mechanism for increasing viscosity of supercritical C02 ・ The viscosity of supercritical C02 is increased by changing its physical state and intermolecular interaction force・ The stacking, mechanism and Lewis acid-base theory can guide the development of synthetic polymer viscosifier and further improve the viscosification effect of supercritical C02 - Supercritical C02 viscosification technology has broad application prospects in the field of C02 fracturing and C02 flooding enhanced oil recovery technology, but its theoretical research is relatively weak, which limits the industrialization process of this technology, and a lot of research needs to be done. [ABSTRACT FROM AUTHOR]

Since the recycling of composites from plant tissues is difficult, extraction of bioactive compounds from plant sources requires pre‐treatment by new technology such as pulsed electric fields (PEF). Due to the reduced consumption of organic solvents, the extractive techniques such as using supercritical CO2 (SC‐CO2) are of interest to researchers. This work aimed to investigating the influences of different parameters of SC‐CO2 (pressure, modifier volume, temperature, and dynamic time) and PEF (frequency and field strength) treatments on the amount extraction of β‐carotene, lycopene, lutein, β‐cryptoxanthin, total phenol content (TPC), and also antioxidant activity percentage of tomato to obtain the optimum circumstances extraction via PEF and SC‐CO2 methods. PEF data showed that treatments with moderate intensity (1 Hz and 0. 25 kV/cm) enhanced the extractability of lycopene (88%), β‐carotene (69%), and β‐cryptoxanthin (24%). The maximum recovery in total polyphenols was achieved at a 1 Hz and 1.75 kV/cm, leading to a 41.68% growth. The SC‐CO2 results showed that extraction at 55°C and 35 MPa, and in a short time of 20 min (without any modifier: methanol) resulted in the highest levels of carotenoids (100% recovery), especially lycopene, and antioxidant activity. Largest value of total polyphenols was obtained at 35 MPa, 35°C, during 30 min, and 250 μL methanol as a modifier (58.79% recovery). Results showed that the extraction of polyphenols, unlike carotenoids, required a modifier. Organic solvents, often called modifiers, are sometimes added to the supercritical fluid to increase the polarity range of the extraction process and to help overcome analyte retention in the matrix. In this study, methanol was used as a modifier in different volumes. Therefore, the SC‐CO2 gentle processing conditions, compared with PEF, improved the recovery of tomato bioactive compounds and antioxidant activity. Nevertheless, further studies are needed to optimize such treatments. [ABSTRACT FROM AUTHOR]

This paper provides a detailed description of the development and experimental results of the supercritical flow experiment payload carried on the TZ-6 cargo spacecraft, as well as a systematic verification of the out-of-cabin deployment experiment. The technical and engineering indicators of the payload deployment experiment are analyzed, and the functional modules of the payload are shown. The paper provides a detailed description of the design, installation location, size, weight, temperature, illumination, pressure, radiation, control, command reception, telemetry data, downlink data, and experimental procedures for the out-of-cabin payload in the extreme conditions of space. The paper presents the annular liquid surface state and temperature oscillation signals obtained from the space experiment and conducts ground matching experiments to verify the results, providing scientific references for the design and condition setting of space experiments and comparisons for the experimental results to obtain the flow field structure under supercritical conditions. The paper provides a specific summary and discussion of the space fluid science experiment project, providing useful references for future long-term in-orbit scientific research using cargo spacecraft. [ABSTRACT FROM AUTHOR]

旨在为鱼油产业的绿色可持续发展提供参考，系统介绍了超临界流体（SCF）技术在鱼油提取、鱼油中二十碳五烯酸（EPA）和二十二碳六烯酸（DHA）富集、鱼油结构改性及微胶囊化中的应用，并对SCF技术在鱼油加工中的发展方向进行展望。鱼油的SCF提取在较低温度和惰性环境中完成，能够有效防止脂质氧化，最大限度保持其天然生物活性。SCF技术可以去除鱼油中的异味、短链脂肪酸等，进一步富集EPA、DHA等ω-3多不饱和脂肪酸，大大提高产品的附加值，SCF还可作为鱼油酶促结构改性的溶剂介质，显著提高产品中EPA和DHA的含量。利用SCF技术生产鱼油微胶囊能够减少有机溶剂的使用，产品质量较好。综上，开发基于SCF技术的集鱼油提取、富集、微胶囊化为一体的连续化工艺，将成为未来研究方向之一。Aiming to provide a reference for the green and sustainable development of the fish oil industry, the application of supercritical fluid (SCF) technology in extraction, enrichment of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), structural modification and microencapsulation of fish oil were systematically introduced. The evolving landscape of SCF technology in fish oil processing was prospected. The SCF extraction of fish oil is completed at a lower temperature and inert environment, which can effectively prevent lipid oxidation and maximize its natural bioactivities. The fishy smell and short-chain fatty acid in fish oil can be removed by SCF technology, while EPA, DHA, and other ω-3 polyunsaturated fatty acids can be further enriched, so the additional value of the product is greatly increased. SCF can also serve as a solvent medium for enzymatic structural modification of fish oil to significantly improve the content of EPA and DHA in the product. The production of fish oil microcapsules produced by SCF technology can reduce the use of organic solvents and the quality of product is better. In conclusion, the development of continuous process based on fish oil extraction, enrichment and microencapsulation with SCF technology will become one of the future research directions.

Fluids in subduction zones significantly influence element mobility, isotope fractionation, and mass transfer. However, unraveling the source, composition, and redox state of fluids in continental subduction zones poses a significant challenge. This study focuses on a granitic melt‐eclogite contact interface, along with adjacent granite and eclogite from the Sulu ultrahigh‐pressure metamorphic belt in East China. The interface exhibits complex mineral assemblages, enriched rare earth elements (REEs), and high field strength elements (HFSEs). Zircon grains from the interface show an age of ∼217 ± 9 Ma, slightly later than peak metamorphism, along with the presence of coesite inclusions. These findings suggest that the interfacial fluid likely formed from the mixing of granitic anatectic melt and aqueous fluid from the eclogite during the initial exhumation of the Sulu terrane. The interaction resulted in the eclogite acquiring substantial REEs and HFSEs, suggesting the interfacial fluid's effective element‐transporting capability and potential supercritical fluid properties. Zircon Ce anomaly and Fe3+/Fe2+ oxybarometer data indicate a highly oxidizing interfacial fluid, analogous to arc magmas in oxygen fugacity. This led to the preferential loss of isotopically heavier Cr from the eclogite during fluid‐eclogite interaction, evidenced by heavier Cr isotopic compositions in the interface (δ53Cr = −0.04 to −0.05‰) compared to adjacent eclogite (δ53Cr as low as −0.11‰). In summary, our results highlight the presence of strong oxidizing and element‐mobilizing fluids in continental subduction zones, offering insights into supercritical fluid recognition and the genesis of oxidizing arc magmas in subduction zones. Plain Language Summary: Fluids are important agents for material migrations in subduction zones, yet the characteristics of fluids in continental subduction zones remain poorly understood, including their redox state, element‐carrying capacity, and isotopic features. In our study, we uncovered a unique interfacial fluid process occurring during the interaction of granitic melt and eclogite in continental subduction zones. This interfacial fluid transported significant amounts of insoluble trace elements into the eclogite, resulting in superchondritic Nb/Ta ratios. These characteristics indicate the interfacial fluid's exceptional element‐transporting capability distinct from silicate melts or aqueous fluids. Additionally, the interfacial fluid demonstrates a strong oxidizing property, comparable to or even exceeding that of arc magmas. This distinctive feature leads to the preferential loss of isotopically heavier Cr in the eclogite during fluid‐rock interaction. In summary, our study provides a compelling demonstration of the presence of strong oxidizing and element‐mobilizing fluids, carrying significant understanding for fluid properties in subduction zones. Key Points: Significant migrations of rare earth elements and high field strength elements are observed in granitic anatectic melt‐eclogite interfaceThe interfacial fluid is highly oxidizing, with oxygen fugacity equivalent to or even surpassing that of arc magmasThe strong oxidizing nature of the interfacial fluid resulted in the preferential loss of isotopically heavier Cr of the eclogite [ABSTRACT FROM AUTHOR]

A supercritical carbon dioxide (SCCO2) fluid, characterized by gas‐like diffusivity, near‐zero surface tension, and excellent mass transfer properties, is used as a precursor to produce silicon oxycarbide (SiOC) coating. SCCO2 disperses and reacts with Si particles to form an interfacial layer consisting of Si, O, and C. After an 850 °C annealing process, a conformal SiOC coating layer forms, resulting in core‐shell Si@SiOC particles. High‐resolution transmission electron microscopy and its X‐ray line‐scan spectroscopy, X‐ray photoelectron spectroscopy, Fourier‐transform infrared spectroscopy, and Raman spectroscopy, are used to examine the SiOC formation mechanism. Effects of SCCO2 interaction time on the SiOC properties are investigated. The SiOC layer connects the Si@SiOC particles, improving electron and Li+ transport. Cyclic voltammetry, galvanostatic intermittent titration technique, and electrochemical impedance spectroscopy are employed to examine the role of SiOC during charging/discharging. Operando X‐ray diffraction data reveal that the SiOC coating reduces crystal size of the formed Li15Si4 and increases its formation/elimination reversibility during cycling. The Si@SiOC electrode shows a capacitiy of 2250 mAh g−1 at 0.2 A g−1. After 500 cycles, the capacity retention is 72% with Coulombic efficiency above 99.8%. A full cell consisting of Si@SiOC anode and LiNi0.8Co0.1Mn0.1O2 cathode is constructed, and its performance is evaluated. [ABSTRACT FROM AUTHOR]

In recent years, the supercritical CO2 extraction method has gained attention due to its use of environmentally friendly, non-toxic solvents, ability to operate at lower temperatures that do not cause the degradation of bioactive compounds, and capacity for rapid extraction. This method is particularly notable for isolating bioactive compounds from plants. The extracts obtained have shown superior properties due to their activity against diseases such as cancer, which is one of the leading causes of death worldwide. The aim of this study is to provide an in-depth understanding of the supercritical CO2 extraction method, as well as to discuss its advantages and disadvantages. Furthermore, the study includes specific data on various plant materials, detailing the following parameters: plant name and region, bioactive compounds or compound classes, extraction temperature (°C), pressure (bar), time (minutes), co-solvent used, and flow rate. Additionally, this study covers extensive research on the isolation of bioactive compounds and the efficacy of the obtained extracts against cancer. [ABSTRACT FROM AUTHOR]

Green and roasted coffee oils are products rich in bioactive compounds, such as linoleic acid and the diterpenes cafestol and kahweol, being a potential ingredient for food and cosmetic industries. An overview of oil extraction techniques most applied for coffee beans and their influence on the oil composition is presented. Both green and roasted coffee oil extractions are highlighted. Pressing, Soxhlet, microwave, and supercritical fluid extraction were the most used techniques used for coffee oil extraction. Conventional Soxhlet is most used on a lab scale, while pressing is most used in industry. Supercritical fluid extraction has also been evaluated mainly due to the environmental approach. One of the highlighted activities in Brazilian agribusiness is the industrialization of oils due to their increasing use in the formulation of cosmetics, pharmaceuticals, and foods. Green coffee oil (raw bean) has desirable bioactive compounds, increasing the interest of private companies and research institutions in its extraction process to preserve the properties contained in the oils. [ABSTRACT FROM AUTHOR]

Copyright of Food & Machinery is the property of Food & Machinery Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: Allograft tendons are perceived to have a high ACL graft failure rate in primary anterior cruciate ligament (ACL) reconstruction (ACLR). Historical series may be biased by graft processing methods that degrade the biomechanical properties of donor tendons such as irradiation. Supercritical carbon dioxide (SCCO2) is a validated method of terminally sterilizing biomaterials at physiological temperatures without irradiation, but in vivo use of SCCO2-processed tendon allografts for primary ACLR has not been reported to date. Hypothesis: ACLR with SCCO2 allografts would result in acceptable failure rates, subjective knee scores, and clinical evaluation at 2 years postoperatively. Study Design: Case series; Level of evidence, 4. Methods: Patients underwent primary ACLR with terminally sterilized SCCO2-processed human gracilis, peroneus longus, semitendinosus, tibialis anterior, and tibialis posterior tendon allografts. Patient demographics were collected, along with tendon donor age and sex. At 1 year postoperatively, subjective International Knee Documentation Committee (IKDC) and ACL–Return to Sport After Injury (ACL-RSI) scores were collected, as well as clinical evaluation. At 2 years postoperatively, the IKDC and ACL-RSI scores were repeated, and return to sports and further knee injuries were recorded. Results: A total of 144 patients with a medianage of 26 (IQR 14) years formed the study group. Patients were predominately male (58%). The loss to follow-up rate was 8% (n = 12). The mean age of allograft tendon donors was 37 (range 17-58) years, and the majority were male (83%). The mean allograft diameter was 8.9 ± 1.0 mm. At 2 years, ACL graft failureoccurred in 5% (n = 7). All graft failureswere in patients aged ≤25 years (P =.007). Neither donor age (≤40 or >40 years) nor donor sex was associated with graft failure (P >.05). The median IKDC subjective score was 95 and ACL-RSI score was 75. There were no revisions for sepsis within the first 2 years postoperatively. Conclusion: SCCO2 processing of allograft tendons demonstrated satisfactory clinical and patient-reported outcomes at 24 months postoperatively in a consecutive series of patients with primary ACLR, with similar ACL graft failure rates and subjective knee scores compared with those reported in published series of hamstring tendon autograft and fresh frozen nonirradiated allograft. [ABSTRACT FROM AUTHOR]

In this study, the techno-economic analysis (TEA) and life cycle assessment (LCA) were used to make a comprehensive comparison from the perspectives of economic and environment between the hydrogenation upgrading process and the supercritical ethanol upgrading process based on fast pyrolysis of cornstalk for liquid biofuel. The whole processes of fast pyrolysis and hydrogenation upgrading (FP-HU), fast pyrolysis, and supercritical ethanol upgrading (FP-SU) were simulated by aspen plus software. The mass flow and energy flow of these two processes were calculated according to the simulation results. The TEA results showed that the minimum fuel selling prices (MFSP) of FP-HU and FP-SU were 0.0417 $/MJ and 0.0383 $/MJ. The largest contribution to the MFSPs of FP-HU and FP-SU were the cornstalk cost (0.0084 $/MJ) and the ethanol input cost (0.012 $/MJ), accounting for 18.8% and 31.3% of their MFSP, respectively. The LCA results showed that the abiotic depletion potential (ADP), chemical oxygen demand (COD), and global warming potential (GWP) values of FP-HU were lower compared with FP-SU. The eco-points representing the combined environmental impact of FP-HU and FP-SU were 4.5E − 12 and 5.2E − 12, respectively. Compared to conventional diesel, the ADP, GWP, and respiratory inorganics (RI) of FP-HU and FP-SU decreased by 25.1% and 8.6%, 66.8% and 51.9%, and 95.7% and 96.6%, respectively. The sub-process contribution analysis suggested that the electricity consumption of bio-oil production sub-process and the ethanol consumption of bio-oil upgrading sub-process contributed the most to the eco-points of FP-HU and FP-SU. [ABSTRACT FROM AUTHOR]

Copyright of Journal of South China University of Technology (Natural Science Edition) is the property of South China University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract The effect of the initial atoms distribution on the molecular dynamics (MD) simulation of a model atomic fluid (argon) is investigated for the case of the isochoric phase transition to the supercritical state. In particular, the case of uniformly distributed atoms in the simulation domain is compared with the case of separated liquid and vapor atoms. The sensitivity of simulations to asymmetric nanoscale perturbations in the boundary is also studied. Despite its high computational cost, the MD approach has the potential to successfully address long‐standing problems in computational fluid dynamics (CFD), especially those associated with mathematical singularities, such as contact angles, vortices, phase transitions and so forth. Unlike conventional CFD simulations, where the initial condition is the pressure or velocity distribution in the simulation domain, MD simulations also require the initial position of each molecule. Thus, it is important to understand whether a judicious choice of the initial distribution of molecules can reduce the overall computation time of the simulation. The evolution of the model fluid system during the phase transition was simulated using a Lennard‐Jones interatomic potential, corrected with the Lorentz–Berthelot mixing rule for the interactions with the solid walls. The system was allowed to relax until equilibrium, and then a Heaviside temperature step was applied to the wall to bring the system to supercritical conditions. Results show the initial choice of the atoms distribution can significantly affect the computational time, while the effect of asymmetric perturbations on the boundary is negligible.

Abstract The SiO2–H2O binary system serves as a basis for understanding complex silicate-water systems. In this study, based on limited existing experimental data of solubility, we propose a new thermodynamic model for SiO2–H2O fluid by modifying the traditional non-random two-liquid model with a simplified polymerization reaction. This model is applicable from 773 K to the anhydrous quartz melting temperature and from 0.5 GPa to at least 2 GPa across the critical conditions. It can predict solid–liquid equilibrium and vapor–liquid equilibrium in good agreement with available experiments. The upper critical endpoint of the SiO2–H2O system is predicted to be at ~ 1.14 ± 0.18 GPa and 1344 ± 87 K. With the new model, we obtain a quantitative three-dimensional pressure–temperature–composition phase diagram of the SiO2–H2O fluid, which greatly facilitates the understanding of the complex phase behavior of this binary around the upper critical endpoint. In addition, since the model is based on the Gibbs free energy foundation, we further discuss the derived density variations of SiO2–H2O fluid along with its complex phase changes in typical geochemical processes.

Extraction of bioactive compounds for application in nutraceuticals is gaining popularity. For this, there is a search for low-cost substrates that would make the end product and the process more economical. Mushroom waste (stalk, cap, stem etc.) is one such high valued substrate that has received much attention recently due to its rich reserves of terpenoids, polyphenols, sesquiterpenes, alkaloids, lactones, sterols, antioxidative vitamins, anthocyanidins, glycoproteins and polysaccharides, among others. However, there is a need to identify green and hybrid technologies that could make the bioactive extraction process from these substrates safe, efficient and sustainable. To this effect, many emerging technologies (supercritical fluid, ultrasound-, enzyme- and microwave-assisted extraction) have been explored in the last decade which have shown potential for scale-up with high productivity. This review systematically discusses such technologies highlighting the current challenges faced during waste processing and the research directives needed for further advancements in the field. [ABSTRACT FROM AUTHOR]

This study proposes a scheme for optimizing the extraction of Damask rose essential oil under supercritical conditions. The effects of temperature, pressure, and static time on the extraction process were investigated using response surface methodology (RSM). The results showed that increasing pressure and static time had a positive effect on extraction, while increasing temperature had a negative effect. The optimal conditions for extraction were found to be 45 °C, 180 bar, and 180 min, with an efficiency of approximately 92% and a content of 54.2% for 2-phenylethanol. The extraction process was modeled using Peng–Robinson equations based on equilibrium data, with values of kij and lij determined as 0.311 and 0.037, respectively. The separation unit was simulated using Aspen Hysys, with operating conditions set at 20 °C and 55 bar. An economic evaluation of the industrial plan was conducted using Aspen Plus. The fixed investment cost (FIC) for the project was calculated as $412,000, and the manufacturing cost was estimated at $220,000. The capital return period for the project was determined to be 8 months, indicating that the initial investment would be recovered within this timeframe. [ABSTRACT FROM AUTHOR]

This study examined a method for de-crosslinking high-density polyethylene (HDPE) for use in heating pipes using supercritical fluids and recycling them into polyethylene. Waste crosslinked HDPE is mostly incinerated because it is a thermosetting plastic and cannot be recycled. Therefore, there is an urgent need to develop new recycling technologies for crosslinked HDPE to prevent environmental pollution. Many experiments have been conducted under various subcritical and supercritical conditions using methanol as the supercritical solvent to recycle crosslinked HDPE. Consequently, PE can be prepared via a de-crosslinking reaction. To recycle crosslinked high-density polyethylene, we conducted experiments at three rotational speeds (80, 250, and 400 rpm) of the screw under the conditions of various temperatures (300–360 ℃) by using methanol, ethanol, acetone, and water. As a result, we could prepare polyethylene with a linear structure at temperatures above 300 ℃ through the de-crosslinking reaction. This study evaluated the characteristics of recycled polyethylene based on the reaction conditions using Fourier transform infrared spectroscopy (FT-IR), gel permeation chromatography (GPC), X-ray diffraction (XRD), differential scanning calorimetry (DSC), and tensile strength analyses. In this study, samples with the same chemical and crystal structures were prepared under all conditions. [ABSTRACT FROM AUTHOR]

An equation of state that predicts the critical thermodynamic behavior of n-butane is formulated. This equation takes into account the global behavior that includes the singular thermodynamic behavior asymptotically close to the critical point and the crossover to the regular thermodynamic behavior far away from the critical point. The formulated equation is based on the transformation of a truncated classical Landau expansion and represents the thermodynamic properties of n-butane in a wide range of temperatures and densities around the critical point. A comparison of the pressure P–ρ–T data measured by Beattie and co-workers and those calculated with the crossover EOS is made. Finally, the specific heat at constant volume, Cv, for n-butane along the critical density within a restricted temperature interval around the critical point is presented. [ABSTRACT FROM AUTHOR]

Supercritical fluid extraction is a successful technique in the field of extraction of different bioactive compounds at the mild temperature conditions. This technique is frequently used for the extraction of plant extracts. In the review, supercritical fluid extraction is investigated from different aspects in regards to extraction from plants, including differences with classical and modern extraction methods, antioxidant and antibacterial strength of extracts obtained by supercritical fluids, representing the effectiveness of the extraction system, and various parameters affecting the extraction yield such as temperature, pressure, time, fluid flow rate, modifier, and sample size. Also, a number of studies concerning the modeling and optimizing of supercritical fluid extraction of plant extracts is also discussed. [ABSTRACT FROM AUTHOR]

The SiO2–H2O binary system serves as a basis for understanding complex silicate-water systems. In this study, based on limited existing experimental data of solubility, we propose a new thermodynamic model for SiO2–H2O fluid by modifying the traditional non-random two-liquid model with a simplified polymerization reaction. This model is applicable from 773 K to the anhydrous quartz melting temperature and from 0.5 GPa to at least 2 GPa across the critical conditions. It can predict solid–liquid equilibrium and vapor–liquid equilibrium in good agreement with available experiments. The upper critical endpoint of the SiO2–H2O system is predicted to be at ~ 1.14 ± 0.18 GPa and 1344 ± 87 K. With the new model, we obtain a quantitative three-dimensional pressure–temperature–composition phase diagram of the SiO2–H2O fluid, which greatly facilitates the understanding of the complex phase behavior of this binary around the upper critical endpoint. In addition, since the model is based on the Gibbs free energy foundation, we further discuss the derived density variations of SiO2–H2O fluid along with its complex phase changes in typical geochemical processes. [ABSTRACT FROM AUTHOR]

An experimental study of the grinding of lidocaine by the rapid expansion of supercritical solutions (RESS metho d) was carried out. The experiments were carried out in the pressure range of 10–35 MPa and temperatures of 308–333 K. The analysis of the morphology and size of particles, as well as the effect of the process parameters on them, was carried out. Qualitative and quantitative spectrophotometric analysis was carried out. The dissolution test was carried out in a phosphate buffered saline medium simulating plasma, which showed that the reduction in particle size gave an increased yield of the drug in a shorter period of time compared to the original drug that was not treated. [ABSTRACT FROM AUTHOR]

Supercritical drying is the only effective method for producing aerogels. Aerogels are innovative materials that found various applications in the range of industries. At the same time, supercritical drying is a technologically complex and expensive process, and an important goal is to optimize the production process to reduce costs and energy consumption. In this paper, the following aspects are considered: Investigation of the influence of parameters on the supercritical drying of silica aerogels on a laboratory scale; Modeling and simulation of the supercritical drying process; Developing a methodology for calculating the cost of manufacturing of silica aerogels; Creating a software module for calculating the cost of manufacturing of silica aerogels and performing techno-economic optimization of the supercritical drying process; Techno-economical optimization of the supercritical drying of silica aerogels on a pilot scale. With the aid of the developed software, techno-economic optimization of the pilot plant of silica aerogels was carried out. The developed mathematical model, optimization approach, and studies of the intensification of the supercritical drying process make it possible to reduce the cost of manufacturing in the existing production of aerogels by 26.4%. [ABSTRACT FROM AUTHOR]

Green chemistry aims at replacing toxic solvents by safer solvents such as supercritical carbon dioxide (scCO2), which displays zero surface tension, outstanding transport properties, high diffusivity, and tuned solubilization by changing the pressure and temperature, or adding cosolvents. Nonetheless, the practical application of scCO2-based technologies under supercritical conditions requires sophisticated systems for optimal operation. Here, we review scCO2-based systems with focus on dyeing, extraction, chromatographic, and cleaning systems. All scCO2-based systems consist of a CO2 supply and pump part, a cosolvent providing part, and a parameters controlling part, yet there are different reaction vessels depending on solute types and practical functions. Developing more normalized, intelligentized, and durable scCO2-based systems should render the scCO2-based technologies be more economic, controllable, flexible, and suitable for wider applications. [ABSTRACT FROM AUTHOR]

Finding different technical procedures to increase the solubility of orally-taken medicines play a vital key role towards reducing their undesirable side effects and improving their therapeutic effectiveness. Low solubility of drugs may result in the emergence of disparate challenges like poor gastro-intestinal absorption, inadequate bioavailability, and difficulty of metabolism. In this research, it has been tried to model the solubility of Alendronate medication based on two input parameters of temperature and pressure. The pressure was considered to be between 120–300 bar, and temperature was set between 308–338 K for the entire analysis. For this purpose, the support vector machine model is considered. This model and the bagging and boosting models that have been used to strengthen it have been evaluated as three different models. Based on the R criterion, the SVR model has a score of 0.926, while Begging and AdaBoost have scores of 0.881 and 0.983, respectively. Based on this, the AdaBoost model can be considered a more successful ensemble model that has increased the SVR performance. Using this ensemble method, the RMSE error rate is 4.30E-02 and MAE is 2.96E-02.

Abstract A supercritical carbon dioxide (SCCO2) fluid, characterized by gas‐like diffusivity, near‐zero surface tension, and excellent mass transfer properties, is used as a precursor to produce silicon oxycarbide (SiOC) coating. SCCO2 disperses and reacts with Si particles to form an interfacial layer consisting of Si, O, and C. After an 850 °C annealing process, a conformal SiOC coating layer forms, resulting in core‐shell Si@SiOC particles. High‐resolution transmission electron microscopy and its X‐ray line‐scan spectroscopy, X‐ray photoelectron spectroscopy, Fourier‐transform infrared spectroscopy, and Raman spectroscopy, are used to examine the SiOC formation mechanism. Effects of SCCO2 interaction time on the SiOC properties are investigated. The SiOC layer connects the Si@SiOC particles, improving electron and Li+ transport. Cyclic voltammetry, galvanostatic intermittent titration technique, and electrochemical impedance spectroscopy are employed to examine the role of SiOC during charging/discharging. Operando X‐ray diffraction data reveal that the SiOC coating reduces crystal size of the formed Li15Si4 and increases its formation/elimination reversibility during cycling. The Si@SiOC electrode shows a capacitiy of 2250 mAh g−1 at 0.2 A g−1. After 500 cycles, the capacity retention is 72% with Coulombic efficiency above 99.8%. A full cell consisting of Si@SiOC anode and LiNi0.8Co0.1Mn0.1O2 cathode is constructed, and its performance is evaluated.

Paeonia officinalis L. is one of the species of the Paeoniaceae family. Its root has different effective compounds e.g., polyphenols, flavonoids, triterpenoids, tannins, and monoterpenes. It shows biological activities such as antibacterial, anti-oxidative, relaxing and anti-pain properties. This study evaluated the effect of three solvents, ethanol/water, water, and water/ethanol/hexane on extracting the active ingredients. These solvents were applied by the methods of immersion, immersion with ultrasonic waves, and the use of supercritical fluid carbon dioxide with auxiliary solvents. The efficiency, qualitative characteristics (pH, polyphenolic compounds and antioxidant properties) and antimicrobial properties of the extracts were evaluated by the well-diffusion method against Escherichia coli, Staphylococcus aureus, Salmonella Typhimurium and Candida albicans. Also, the MIC and MBC of the extracts on the activity of these organisms were determined. The results showed that the independent variables significantly affect the quantity and quality of the produced extracts (P ≤ 0.05). Using the water/ethanol, and the immersion method in combination with ultrasonic waves, the highest extract efficiency (17.66± 0.34), of the phenolic compounds (33.5±0.65) and antioxidant property (76±1.44) was obtained. The diameter of the inhibition zone for E. coli, S. aureus and C. albicans in the vicinity of this sample was more than others. Meanwhile, the inhibition zone of S. Typhimurium was larger in the presence of watery extract using the immersion method. The quantity and quality of the extract using supercritical fluid was lower than others.

[Display omitted] The copper-catalyzed azide–alkyne cycloaddition of BODIPY acetylene derivative and ferrocene azides in supercritical CO 2 at 80 °C and 81 bar affords the corresponding triazole-containing BODIPY–ferrocene conjugates in high yields. The fluorescent and electrochemical properties of the compounds thus obtained were explored. [ABSTRACT FROM AUTHOR]

This paper provides a detailed description of the development and experimental results of the supercritical flow experiment payload carried on the TZ-6 cargo spacecraft, as well as a systematic verification of the out-of-cabin deployment experiment. The technical and engineering indicators of the payload deployment experiment are analyzed, and the functional modules of the payload are shown. The paper provides a detailed description of the design, installation location, size, weight, temperature, illumination, pressure, radiation, control, command reception, telemetry data, downlink data, and experimental procedures for the out-of-cabin payload in the extreme conditions of space. The paper presents the annular liquid surface state and temperature oscillation signals obtained from the space experiment and conducts ground matching experiments to verify the results, providing scientific references for the design and condition setting of space experiments and comparisons for the experimental results to obtain the flow field structure under supercritical conditions. The paper provides a specific summary and discussion of the space fluid science experiment project, providing useful references for future long-term in-orbit scientific research using cargo spacecraft.

Photocatalytic hydrogen generation from water is one of the promising approaches for direct solar-to-fuel conversion to address the energy crisis. Developing an efficient, cost-effective, durable photocatalyst for sustainable hydrogen production is a great challenge in this technology. Metal chalcogenides are widely used potential materials in the photocatalysis field; however, metal sulfides are photocorrosive in nature compared to metal selenides, which limits their application. Herein, supercritical fluid becomes completely compatible with photocatalyst preparation, as it controls the morphology of materials. The synthesis of CoSe and NiSe using a homogeneous, one-pot synthesis of supercritical fluid processing with a very short reaction time of 30 min has been demonstrated, and then they are coupled with a TiO2 photocatalyst to improve the hydrogen production rate. Due to the conductive nature of metal selenides (CoSe and NiSe), fast electron transfer and charge separation are highly feasible, which help to improve the hydrogen production rate. Various weight percentages of the metal selenide (CoSe or NiSe)/TiO2 nanocomposite were prepared, and photocatalytic activity was examined using glycerol and lactic acid as hole scavengers. The CoSe/TiO2 and NiSe/TiO2 nanocomposites showed maximum hydrogen evolution rates of 202.2 and 169 mmol/h/gcat, respectively, which are very close to that of 1 wt % Pt/TiO2. In this context, metal selenides (CoSe/NiSe) are promising cocatalysts for TiO2 toward viable hydrogen production. [ABSTRACT FROM AUTHOR]

This paper studies supercritical argon adsorption in connected pores composed of cavity and neck by using a grand canonical Monte Carlo simulation. The effect of pressure, temperature, and cavity size were investigated systematically on the absolute and excess densities. Moreover, the sub-isotherm adsorption in the cavity and neck was also explored individually. We found that when the cavity is significantly larger than the neck, the total excess isotherm has three clear peaks, which are governed by the neck, cavity, and closed end. The first peak at low pressure is mainly caused by the adsorption in the pore neck, the second peak at higher pressure is largely in order to fill the cavity, and the third peak at higher pressure occurs because adsorbate molecules accumulate between previously adsorbed layers at the closed end. Thus, the peaks are found when the derivation of bulk density and absolute pore density in each section is almost equal. Furthermore, when the temperature is increased, the first and third peaks disappear slightly because the kinetic energy at high temperature reduces the fluid–solid and fluid–fluid interactions. Therefore, a plateau behavior in high-pressure isotherm can be observed because of the interplay between the effects of the closed end and high temperature in pore connectivity. The feature changes to a single peak prior to an increasing at high pressures when N2 adsorption is considered. Due to its molecular length is relatively large to the pore structures. This study offers the knowledge to understand and develop supercritical fluid in pore connectivity. [ABSTRACT FROM AUTHOR]

Ducted fuel injection (DFI) is a proposed fuel injection concept for achieving substantial reductions in emissions. In this concept, the fuel is injected through a coannular duct, resulting in increased fuel-air mixing and minimized formation of soot and other unwanted combustion products. Apart from comprehensive experimental investigations on DFI, so far computational studies have been limited to single-point Reynolds-averaged Navier Stokes simulations. Therefore, the objective of this work is to complement these studies by performing large-eddy simulations using a diffuse-interface method to examine the physical mechanisms and combustion processes of DFI, specifically focusing on the mixing process and the effect of fuel-ducting on combustion and pollutant emissions. To this end, finite-rate chemistry simulations are performed of the DFI configuration corresponding to the Engine Combustion Network Spray A injector at transcritical conditions (n-dodecane fuel, 60 bar pressure and 1000 K temperature chamber conditions). A two-equation soot model is employed for the qualitative analysis of soot emissions. Direct comparisons of averaged and instantaneous flow field results with the Spray A configuration are performed to assess the effect of DFI on the first- and second-stage ignition and soot formation. Compared to the free-spray condition, the results show that the DFI case exhibits a combination of (i) increased mass flow rate and entrained air, (ii) larger pressure drop magnitude and flow velocity, and (iii) a closer-to-stoichiometric mixture composition (both globally and locally), each of which is conjectured to contribute toward reduced soot production. [ABSTRACT FROM AUTHOR]

Sterilization of structural bone allografts is a critical process prior to their clinical use in large cortical bone defects. Gamma irradiation protocols are known to affect tissue integrity in a dose dependent manner. Alternative sterilization treatments, such as supercritical carbon dioxide (SCCO2), are gaining popularity due to advantages such as minimal exposure to denaturants, the lack of toxic residues, superior tissue penetration, and minor impacts on mechanical properties including strength and stiffness. The impact of SCCO2 on the fracture toughness of bone tissue, however, remains unknown. Here, we evaluate crack initiation and growth toughness after 2, 6, and 24 h SCCO2‐treatment using Novakill™ and ethanol as additives on ~11 samples per group obtained from a pair of femur diaphyses of a canine. All mechanical testing was performed at ambient air after 24 h soaking in Hanks' balanced salt solution (HBSS). Results show no statistically significant difference in the failure characteristics of the Novakill™‐treated groups whereas crack growth toughness after 6 and 24 h of treatment with ethanol significantly increases by 37% (p =.010) and 34% (p =.038), respectively, compared to an untreated control group. In contrast, standard 25 kGy gamma irradiation causes significantly reduced crack growth resistance by 40% (p =.007) compared to untreated bone. FTIR vibrational spectroscopy, conducted after testing, reveals a consistent trend of statistically significant differences (p <.001) with fracture toughness. These trends align with variations in the ratios of enzymatic mature to immature crosslinks in the collagen structure, suggesting a potential association with fracture toughness. Additional Raman spectroscopy after testing shows a similar trend with statistically significant differences (p <.005), which further supports that collagen structural changes occur in the SCF‐treated groups with ethanol after 6 and 24 h. Our work reveals the benefits of SCCO2 sterilization compared to gamma irradiation. [ABSTRACT FROM AUTHOR]

This study proposes to further exploit the potential of the carbon dioxide supercritical anti-solvent precipitation (SAS) process by using liquefied gas as a feed solvent in the SAS process. In this study, liquefied dimethyl ether (DME) is compared to conventional ethyl acetate as the feed solvent for β-carotene. DME is a gas in its standard state, and when it is made into a subcritical liquefied gas, it has a larger self-diffusion coefficient and saturated vapor pressure, and smaller viscosity and surface tension than liquid solvents. Because of these characteristics of liquefied DME, liquefied DME prevents primary particle agglomeration and DME residue. When ethyl acetate was used as the feed solvent, the conditions giving the smallest particles were 60 °C and 12 MPa, and 31 ± 5 nm primary particles of β-carotene were obtained. However, most of these were aggregated into secondary particles of several hundred nanometers. In the case of liquefied DME, the condition giving the smallest particles was 40 °C and 12 MPa, and primary particles of 58 ± 8 nm β-carotene were dispersed without aggregation. Furthermore, FT-IR analysis detected residual ethyl acetate in the aggregated β-carotene particles, whereas DME was not detected in the dispersed particles. Liquefied DME is likely to be a suitable solvent for the micronization of heat-sensitive substances using the SAS method without agglomeration. Combining various liquefied gases, not just DME, with the SAS process may create possibilities for applying the SAS process to target materials that are insoluble in conventional liquid solvents and for synthesizing even finer nanoparticles.

In recent years, the supercritical CO2 extraction method has gained attention due to its use of environmentally friendly, non-toxic solvents, ability to operate at lower temperatures that do not cause the degradation of bioactive compounds, and capacity for rapid extraction. This method is particularly notable for isolating bioactive compounds from plants. The extracts obtained have shown superior properties due to their activity against diseases such as cancer, which is one of the leading causes of death worldwide. The aim of this study is to provide an in-depth understanding of the supercritical CO2 extraction method, as well as to discuss its advantages and disadvantages. Furthermore, the study includes specific data on various plant materials, detailing the following parameters: plant name and region, bioactive compounds or compound classes, extraction temperature (°C), pressure (bar), time (minutes), co-solvent used, and flow rate. Additionally, this study covers extensive research on the isolation of bioactive compounds and the efficacy of the obtained extracts against cancer.

Yaha condensate gas reservoir is condensate gas reservoir developed by gas injection in the Tarim Basin. The practice of gas injection in condensate gas reservoir shows that the key to improve gas injection effect is to control gas channeling. Dynamic monitoring shows that there is no instantaneous miscibility between dry gas and condensate gas during gas injection. Based on the principle of entropy increase and mass transfer kinetics, the phase behavior of condensate gas and dry gas in reservoir is analyzed theoretically. The new technique to improve condensate recovery is adopted for condensate gas field. By using the density difference and seepage characteristics of dry gas and condensate gas, the injected dry gas cap is formed at the top of the gas reservoir, and the three-dimensional displacement is realized by the expansion of dry gas cap. Gas injection gravity assisted flooding technology is to realize vertical displacement of injected gas through the expansion of dry gas cap by using gravity differentiation caused by gas density difference. This technology can keep the front edge of gas injection advance evenly and solve the problem of gas channeling in the process of cyclic gas injection.

Paeonia officinalis L. is one of the species of the Paeoniaceae family. Its root has different effective compounds e.g., polyphenols, flavonoids, triterpenoids, tannins, and monoterpenes. It shows biological activities such as antibacterial, anti-oxidative, relaxing and anti-pain properties. This study evaluated the effect of three solvents, ethanol/water, water, and water/ethanol/hexane on extracting the active ingredients. These solvents were applied by the methods of immersion, immersion with ultrasonic waves, and the use of supercritical fluid carbon dioxide with auxiliary solvents. The efficiency, qualitative characteristics (pH, polyphenolic compounds and antioxidant properties) and antimicrobial properties of the extracts were evaluated by the well-diffusion method against Escherichia coli, Staphylococcus aureus, Salmonella Typhimurium and Candida albicans. Also, the MIC and MBC of the extracts on the activity of these organisms were determined. The results showed that the independent variables significantly affect the quantity and quality of the produced extracts (P ≤ 0.05). Using the water/ethanol, and the immersion method in combination with ultrasonic waves, the highest extract efficiency (17.66± 0.34), of the phenolic compounds (33.5±0.65) and antioxidant property (76±1.44) was obtained. The diameter of the inhibition zone for E. coli, S. aureus and C. albicans in the vicinity of this sample was more than others. Meanwhile, the inhibition zone of S. Typhimurium was larger in the presence of watery extract using the immersion method. The quantity and quality of the extract using supercritical fluid was lower than others.