Key words: supercritical fluid, solubility, prediction, machine learning
A review of researches devoted to the application of machine learning methods and neural network technologies in the prediction of solubility of various substances in supercritical (SC) fluids. Using a simple neural network of three layers a prototype of a solubility prediction system was developed based on the example of an existing data set on the solubility of aromatic hydrocarbons in SC carbon dioxide. Its efficiency has been shown and further directions of research in this field have been identified.
doi:10.34984/SCFTP.2024.19.3.001
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ГОСТ
7.0.100-2018
Сapabilities of machine learning methods in prediction of solubility of substances in supercritical carbon dioxide / – Текст : // Сверхкритические Флюиды: Теория и Практика.. – 2024. – Т. 19. – № 3. – С. 4-12. - DOI: 10.34984/SCFTP.2024.19.3.001
TRANSLIT
Vozmozhnosti metodov mashinnogo obucheniya v zadachah prognozirovaniya rastvorimosti veshchestv v sverhkriticheskom diokside ugleroda / – Tekst : // Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2024. – Т. 19. – № 3. – S. 4-12. - DOI: 10.34984/SCFTP.2024.19.3.001
En
Сapabilities of machine learning methods in prediction of solubility of substances in supercritical carbon dioxide. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 3, 4-12 (2024). https://doi.org/10.34984/SCFTP.2024.19.3.001
Key words: chitosan, alginate, magnetite, aerogel, supercritical fluid technologies.
Composite aerogels were obtained based on two-component sodium alginate—chitosan hydrogels with the inclusion of magnetite and subsequent drying in supercritical carbon dioxide. The optimal concentration of magnetite introduced into the sodium alginate— chitosan system and the mode of supercritical drying of composite hydrogels in the carbon dioxide were experimentally established, making it possible to obtain the aerogel with a maximally developed porous structure. Using the method of low-temperature nitrogen adsorption, it was shown that the resulting aerogels are characterized by a developed mesoporous structure with open cylindrical pores, the maximum specific surface is 300 m2/g. Experimental studies have shown that the developed composite magnetite-containing aerogels have high bactericidal activity against S. aureus, E. coli and B. subtilis, due to which they have great potential for creating various medical products based on them, including wound dressings, carriers active medicinal substances, hemostatic or sorption materials.
doi:10.34984/SCFTP.2024.19.3.002
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ГОСТ
7.0.100-2018
Preparation magnetite-containing composite aerogels based on alginate-chitosan complex / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2024. – Т. 19. – № 3. – С. 13-29. - DOI: 10.34984/SCFTP.2024.19.3.002
TRANSLIT
Poluchenie magnetitsoderzhashchih kompozitnyh aerogelej na osnove kompleksa al'ginat- hitozan / – Tekst : neposredstvennyj // Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2024. – Т. 19. – № 3. – S. 13-29. - DOI: 10.34984/SCFTP.2024.19.3.002
En
Preparation magnetite-containing composite aerogels based on alginate-chitosan complex. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 3, 13-29 (2024). https://doi.org/10.34984/SCFTP.2024.19.3.002
Key words: aerogels, gC3N4, sulfides, photocatalysis, oxidation
Composites of gC3N4 particles immobilized in monolithic silica aerogel have been obtained and their physicochemical photocatalytic properties have been studied. Their manifold recyclability and higher, compared to the gC3N4 in its free form, photocatalytic activity in reactions of alkyl aryl sulfides oxidation by molecular oxygen in SC-CO2 medium have been shown. The results presented in this work can serve as a basis for the development of sustainable and efficient processes of organic compounds oxidation.
doi:10.34984/SCFTP.2024.19.3.003
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ГОСТ
7.0.100-2018
Composites of graphitic carbon nitride with silica aerogel – recyclable immobilized photocatalysts for sulfides oxidation by oxygen in SC-CO<sub>2</sub> / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2024. – Т. 19. – № 3. – С. 30-46. - DOI: 10.34984/SCFTP.2024.19.3.003
TRANSLIT
Kompozity grafitopodobnogo nitrida ugleroda s silikatnym aerogelem – recikliziruemye immobilizovannye fotokatalizatory reakcii okisleniya sulfidov kislorodom v srede SC-CO<sub>2</sub> / – Tekst : neposredstvennyj // Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2024. – Т. 19. – № 3. – S. 30-46. - DOI: 10.34984/SCFTP.2024.19.3.003
En
Composites of graphitic carbon nitride with silica aerogel – recyclable immobilized photocatalysts for sulfides oxidation by oxygen in SC-CO<sub>2</sub>. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 3, 30-46 (2024). https://doi.org/10.34984/SCFTP.2024.19.3.003
Key words: polylactide, foaming, supercritical carbon dioxide, laser radiation, dynamic scattering, mobility of interphase boundaries
Multiple scattering of laser radiation on the structure of forming porous matrices results in spatiotemporal fluctuations of intensity in the scattered radiation field (dynamic speckle modulation). Using the effect of dynamic scattering of laser radiation in the volume of evolving foams, the process of formation of highly porous polylactide matrices during their synthesis by the supercritical (SC) fluid foaming method in a carbon dioxide medium is analyzed. The average lifetime of dynamic speckles, τlt, which are recorded using a high-speed CMOS camera, is considered as a parameter carrying information on the ensemble-averaged mobility of scattering centers (boundaries of developing pores). A phenomenological model has been developed that establishes the relationship between the current values of τlt, macroscopic parameters of the foam (volume and rate of its change) and the ensemble-averaged microscopic mobility of interphase boundaries (the first derivative of the average pore size over time). The experimental data interpretation using the developed model on the dynamics of polylactide foam expansion during rapid (0.03 MPa/s) and slow (0.006 MPa/s) pressure release of SC-CO2 in the reactor are presented. It is established that in the case of rapid pressure release, structural
rearrangements in the foam volume continue even after it reaches the maximum value of
the expansion factor. A qualitative interpretation of this feature is given based on the
concepts of thermodynamic nonequilibrium of porous matrices during their formation.
doi:10.34984/SCFTP.2024.19.3.004
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ГОСТ
7.0.100-2018
Dynamic scattering of laser radiation by polylactide foams in the course of their synthesis using the supercritical fluid foaming method: analysis of the interphase boundary mobility / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2024. – Т. 19. – № 3. – С. 47-65. - DOI: 10.34984/SCFTP.2024.19.3.004
TRANSLIT
Dinamicheskoe rasseyanie lazernogo izlucheniya polilaktidnymi penami v processe sinteza metodom sverkriticheskogo flyuidnogo vspenivaniya: analiz podvizhnosti mezhfaznyh granic / – Tekst : neposredstvennyj // Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2024. – Т. 19. – № 3. – S. 47-65. - DOI: 10.34984/SCFTP.2024.19.3.004
En
Dynamic scattering of laser radiation by polylactide foams in the course of their synthesis using the supercritical fluid foaming method: analysis of the interphase boundary mobility. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 3, 47-65 (2024). https://doi.org/10.34984/SCFTP.2024.19.3.004
Key words: mixed oxides, synthesis, water fluid, lanthanum, group IIA elements, aluminates, catalytic oxidation, oxidative coupling of methane
The formation of mixed oxides in La2O3/MO—Al2O3 systems (M is a group IIA element: Mg, Ca, Sr or Ba) during high-temperature treatment and treatment with water fluids (WF) has been studied. It has been shown that high-temperature treatment of the corresponding group IIA metal aluminate with supported lanthanum nitrate leads to the formation of LaAlO3 only in the case of the Mg-containing system. In other cases, there is no transformation of the initial aluminates, and lanthanum oxide is formed. When treating La/M—Al ternary systems with WF, the formation of LaAlO3 is observed in all cases. Also, in all samples, except for Ba-containing, phases of free metal oxides of group IIA elements appear. The increase in activity and selectivity in the OCM process in La/M—Al ternary oxide systems compared to double M—Al systems is associated with the presence of a separate La2O3 oxide phase.
doi:10.34984/SCFTP.2024.19.3.005
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ГОСТ
7.0.100-2018
Formation of compounds and phases in oxide systems La-M-Al (M – Ca, Mg, Sr, Ba) during treatment with water fluid and their catalytic properties in oxidative coupling of methane / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2024. – Т. 19. – № 3. – С. 66-78. - DOI: 10.34984/SCFTP.2024.19.3.005
TRANSLIT
Sistemah La-M-Al (M – Ca, Mg, Sr, Ba) pri obrabotke vodnym flyuidom i ih kataliticheskie svojstva v processe okislitelnoj kondensacii metana / – Tekst : neposredstvennyj // Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2024. – Т. 19. – № 3. – S. 66-78. - DOI: 10.34984/SCFTP.2024.19.3.005
En
Formation of compounds and phases in oxide systems La-M-Al (M – Ca, Mg, Sr, Ba) during treatment with water fluid and their catalytic properties in oxidative coupling of methane. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 3, 66-78 (2024). https://doi.org/10.34984/SCFTP.2024.19.3.005
Key words: subcritical water, agro-industrial complex wastes, buckwheat husk, polyphenols, anti-acetylcholinesterase activity
The effect of the extraction method and conditions on polyphenol composition of buckwheat (Fagopyrum esculentum) husk extracts and their acetylcholinesterase (AChE) inhibition activity was studied. The extracts were obtained both by the traditional method of water-ethanol extraction and in a subcritical water (SBW) medium at 120—220 °C. A direct correlation was found between anticholinesterase activity and the content of polyphenols in the extracts. The highest activity in inhibiting AChE was demonstrated by the extract obtained in the SBW medium at 220 °C, which contains the maximum amounts of the sum of polyphenols and flavonoids. This indicates the decisive role of these compounds in AChE inhibition. The obtained data allow us to consider such extracts as inexpensive and renewable sources of polyphenolic compounds and flavonoids with P-vitamin and neuroprotective activity.
doi:10.34984/SCFTP.2024.19.3.006
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ГОСТ
7.0.100-2018
Effect of extraction method and conditions on the polyphenol content in buckwheat husk (<i>Fagopyrum esculentum</i>) extracts and their activity in acetylcholinesterase inhibition / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2024. – Т. 19. – № 3. – С. 79-92. - DOI: 10.34984/SCFTP.2024.19.3.006
TRANSLIT
Vliyanie metoda i uslovij ekstrakcii na soderzhanie polifenolov v ekstraktah luzgi grechihi (<i>Fagopyrum esculentum</i>) i ih aktivnost v ingibirovanii acetilholinesterazy / – Tekst : neposredstvennyj // Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2024. – Т. 19. – № 3. – S. 79-92. - DOI: 10.34984/SCFTP.2024.19.3.006
En
Effect of extraction method and conditions on the polyphenol content in buckwheat husk (<i>Fagopyrum esculentum</i>) extracts and their activity in acetylcholinesterase inhibition. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 3, 79-92 (2024). https://doi.org/10.34984/SCFTP.2024.19.3.006
Key words: carbon dioxide, N-isopropylacrilamide, solubility, solubility isotherms, phase equilibrium, Chrastil’s model.
Solubility isotherms of N-isopropylacrylamide (NIPAM), obtained via visual synthetic method at temperatures 304.8—353.0 K and pressures 0.1—40.0 MPa, are reported in the current paper. The maximal solubility of NIPAM within this range of parameters is determined as well. The crossover region in regards to the P mix = ƒ (x, mol. %) isotherms is located and the nature of the phenomenon is discussed further. Predictive ability of the Chrastil’s model is evaluated in relation to the NIPAM-CO2 system.
doi:10.34984/SCFTP.2024.19.3.007
Cite
ГОСТ
7.0.100-2018
Solubility of N-isopropylacrylamide in carbon dioxide / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2024. – Т. 19. – № 3. – С. 93-106. - DOI: 10.34984/SCFTP.2024.19.3.007
TRANSLIT
Rastvorimost N-izopropilakrilamida v diokside ugleroda / – Tekst : neposredstvennyj // Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2024. – Т. 19. – № 3. – S. 93-106. - DOI: 10.34984/SCFTP.2024.19.3.007
En
Solubility of n-isopropylacrylamide in carbon dioxide. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 3, 93-106 (2024). https://doi.org/10.34984/SCFTP.2024.19.3.007