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Marín, Sabrina, Mayra Cortés, Mauricio Acosta, Karla Delgado, Camila Escuti, Diego Ayma, and Cecilia Demergasso. "From Laboratory towards Industrial Operation: Biomarkers for Acidophilic Metabolic Activity in Bioleaching Systems." Genes 12, no. 4 (March 25, 2021): 474. http://dx.doi.org/10.3390/genes12040474.
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In the actual mining scenario, copper bioleaching, mainly raw mined material known as run-of-mine (ROM) copper bioleaching, is the best alternative for the treatment of marginal resources that are not currently considered part of the profitable reserves because of the cost associated with leading technologies in copper extraction. It is foreseen that bioleaching will play a complementary role in either concentration—as it does in Minera Escondida Ltd. (MEL)—or chloride main leaching plants. In that way, it will be possible to maximize mines with installed solvent-extraction and electrowinning capacities that have not been operative since the depletion of their oxide ores. One of the main obstacles for widening bioleaching technology applications is the lack of knowledge about the key events and the attributes of the technology’s critical events at the industrial level and mainly in ROM copper bioleaching industrial operations. It is relevant to assess the bed environment where the bacteria–mineral interaction occurs to learn about the limiting factors determining the leaching rate. Thus, due to inability to accurately determine in-situ key variables, their indirect assessment was evaluated by quantifying microbial metabolic-associated responses. Several candidate marker genes were selected to represent the predominant components of the microbial community inhabiting the industrial heap and the metabolisms involved in microbial responses to changes in the heap environment that affect the process performance. The microbial community’s predominant components were Acidithiobacillus ferrooxidans, At. thiooxidans, Leptospirillum ferriphilum, and Sulfobacillus sp. Oxygen reduction, CO2 and N2 fixation/uptake, iron and sulfur oxidation, and response to osmotic stress were the metabolisms selected regarding research results previously reported in the system. After that, qPCR primers for each candidate gene were designed and validated. The expression profile of the selected genes vs. environmental key variables in pure cultures, column-leaching tests, and the industrial bioleaching heap was defined. We presented the results obtained from the industrial validation of the marker genes selected for assessing CO2 and N2 availability, osmotic stress response, as well as ferrous iron and sulfur oxidation activity in the bioleaching heap process of MEL. We demonstrated that molecular markers are useful for assessing limiting factors like nutrients and air supply, and the impact of the quality of recycled solutions. We also learned about the attributes of variables like CO2, ammonium, and sulfate levels that affect the industrial ROM-scale operation.
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Esan, Olaseni Segun, Medinat Olubunmi Osundiya, Christopher Olumuyiwa Aboluwoye, Owoyomi Olanrewaju, and Jide Ige. "Thermodynamic and Interfacial Properties of DTABr/CTABr Mixed Surfactant Systems in Ethanolamine/Water Mixtures: A Conductometry Study." ISRN Thermodynamics 2013 (December 17, 2013): 1–7. http://dx.doi.org/10.1155/2013/280101.
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Mixed-micelle formation in the binary mixtures of dodecyltrimethylammonium bromide (DTABr) and cetyltrimethylammonium bromide (CTABr) surfactants in water-ethanolamine mixed solvent systems has been studied by conductometric method in the temperature range of 298.1 to 313.1 K at 5 K intervals. It was observed that the presence of ethanolamine forced the formation of mixed micelle to lower total surfactant concentration than in water only. The synergistic interaction was quantitatively investigated using the theoretical models of Clint and Rubingh. The interaction parameter β12 was negative at all the mole fractions of DTABr in the surfactant mixtures indicating a strong synergistic interaction, with the presence of ethanolamine in the solvent system resulting in a more enhanced synergism in micelle formation than in water only. The free energy of micellization ΔGM values was more negative in water-ethanolamine mixed solvent system than in pure water indicating more spontaneity in mixed micelle formation in the presence of ethanolamine than in pure water.
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Gredmaier, Ludwig, Sabine Grüner-Lempart, Julian Eckert, Rainer Joachim, and Peter Funke. "Gas-to-aqueous Phase Transfer for Three Paint Solvents Injected into an Abiotic, Industrial Biotrickling Filter Measured with a Flame Ionization Detector." Periodica Polytechnica Chemical Engineering 66, no. 1 (November 26, 2021): 91–100. http://dx.doi.org/10.3311/ppch.18131.
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This is a knowledge contribution to the unsatisfactory biodegradation problem, when biotrickling filters are purifying mixed paint solvents. A biotrickling filter manufacturer reported low biodegradation rates during the purification of a hydrocarbon pollutant mix from an industrial paint spraying floor. From a gas chromatograph/mass spectrometer analysis both hydrophilic and hydrophobic solvents were found in the polluted air. It is known that biodegradation is retarded, if the pollutant does not transfer from gas to liquid into the biofilm and it was therefore suspected that hydrophobic pollutants do not sufficiently migrate into the water/biofilm. To test this hypothesis, pure, rather than mixed pollutants, were injected into the abiotic biotrickling filter. When hydrophobic paint solvent (xylene) was sprayed into the biotrickling filter, the solvent load at the outlet of the filter was almost as high as at the inlet. But when pure, hydrophilic paint solvent (PGME) was sprayed into the abiotic biotrickling filter, the solvent load measured at the outlet of the filter was zero, indicating complete dissolution into the circulation water. Carbon/solvent loads at the filter outlet and inlet were measured with a portable flame ionization detector instrument. The experiment confirms that the hydrophobic solvent does not migrate into the liquid phase. This poor mass transfer of hydrophobic solvents is likely to be the reason for the low biodegradation rate. The result is highly relevant to the paint spraying industry and manufacturers of exhaust gas treatment equipment alike, who spend millions in non-sustainable incineration of exhaust gases.
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Yoshikawa, Makoto, Kotaro Yamamoto, Zhiyun Noda, Masahiro Yasutake, Tatsumi Kitahara, Yuya Tachikawa, Stephen Matthew Lyth, Akari Hayashi, Junko Matsuda, and Kazunari Sasaki. "Self-Supporting Microporous Layer for Polymer Electrolyte Fuel Cells." ECS Meeting Abstracts MA2023-02, no. 37 (December 22, 2023): 1734. http://dx.doi.org/10.1149/ma2023-02371734mtgabs.
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Introduction Improving power density is desired in research and development of polymer electrolyte fuel cells (PEFC) [1-5]. A reduction of gas diffusion resistance by down-thinning the gas diffusion layer (GDL) less than 50 μm is desirable [2]. Whilst both the electrocatalyst layers and electrolyte membrane are around 10 μm, the GDL is still relatively thick at about 150 μm [1]. The previous study investigated the possibility and technical issues in using high-strength and thin, porous metallic GDLs [3]. Based on such previous studies, this study aims to develop a self-supporting thin MPL/GDL with improved power density by creating conductive paths and reducing contact resistance with microporous layer (MPL) deposited on various GDLs. Experimental In this study, MPL was screen-printed on various mesh GDLs as substrates. Cells were fabricated by using these materials, and current-voltage characteristics and microstructural observations were performed. Stainless steel (SUS316 977mesh, 28 μm thick), titanium (200mesh, 152 μm thick), and carbon fiber (45 μm thick) were used as mesh GDL materials. The MPLs were composed of carbon black, carbon nanotubes, polytetrafluoroethylene (PTFE), and solvent (a mixture of polyethylene glycol 600 and pure water), which were mixed, screen printed, and heat treated at 300°C for 30 min to fabricate the MPL/GDL. Conventional materials such as Pt/C (TEC10E50E, Tanaka Kikinzoku, Japan) were used for preparing membrane-electrode-assemblies (MEAs). In the electrochemical characterization of this study, current-voltage characteristics were evaluated using an electrochemical impedance analyzer (SAS SP-240, Bio-Logic Science Instruments, France), and various overvoltages were separated. Results and discussion Figure 1 shows the current-voltage characteristics of cells using various MPL/GDLs. The thickness of MPL/GDLs fabricated was ranging from 62 to 180 μm. For comparison, the characteristics of a cell using a standard material, commercially available MPL/GDL (22BB, SGL Carbon, Germany), are also shown. The results indicate that the use of any kind of these MPLs improves cell performance. The electrochemical performance with metallic GDLs was considerably improved by applying MPLs. In particular, GDLs with metallic meshes made of SUS316 show a significant improvement in current-voltage characteristics by depositing MPLs. The activation overvoltage and ohmic overvoltage were comparable to those of 22BB, the commercial GDL/MPL. This is because the contact resistance between the GDL and the catalyst layer is reduced by the carbon component in the MPL, and the electrical conductivity is improved. The concentration overvoltage was also suppressed by depositing the MPL. The cell performance with MPL3/SUS316 977mesh was comparable to that of 22BB. In the future, we aim to further reduce the concentration overvoltage by optimizing e.g., the content of hydrophilic components in MPLs. Acknowledgment This paper is based on results obtained from a project, JPNP20003, commissioned by the New Energy and Industrial Technology Development Organization (NEDO). References Takahashi, T. Ikeda, K. Murata, O. Hotaka, S. Hasegawa, Y. Tachikawa, M. Nishihara, J. Matsuda, T. Kitahara, M. Lyth, A. Hayashi, and K. Sasaki, J. Electrochem. Soc., 169, 044523, (2022). New Energy and Industrial Technology Development Organization (NEDO), Roadmap of Fuel Cells for Heavy-Duty Vehicles, 48, (2022), (in Japanese), https://www.nedo.go.jp/content/100944011.pdf Yamamoto, M. Yasutake, Z. Noda, S. M. Lyth, J. Matsuda, M. Nishihara, A. Hayashi, and K. Sasaki, ECS Trans., 109 (9),265 (2022). Larminie and A. Dicks, Fuel Cell Systems Explained, 2nd ed., John Wiley & Sons, England, 2003. Kitahara, T. Konomi, H. Nakajima, and J. Shiraishi, Kikai B, 76 (761), 101, (2010). Figure 1
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Tyunina, E. Yu, and M. D. Chekunova. "LiAsF6 SOLUTIONS IN THE MIXED SOLVENTS OF PROPYLENE CARBONATE – DIMETHYL SULFOXIDE: ELECTRIC CONDUCTIVITY AND ELECTROCHEMICAL STABILITY." Электрохимия 59, no. 12 (December 1, 2023): 872–83. http://dx.doi.org/10.31857/s0424857023120137.
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The specific conductivities of LiAsF6 solutions in a mixed solvent of propylene carbonate (PC) –dimethyl sulfoxide (DMSO) were measured at temperatures of 253.15, 263.15, 273.15, 283.15, 293.15, 303.15, 313.15, 323.15 and 333.15 K being a ionophore concentration of 0.2 to 1.4 mol / kg. The portion of DMSO in the mixed solvent was varied in the range of (0.2 - 0.75) mole fractions. The specific conductivities of LiAsF6 in DMSO were studied in the temperature range of (293.15 – 333.15) K. Concentration dependences of specific conductivity of the system can be described by the Casteel-Amis equation. The contributions of the solvent and ionophore to the activation energy of the ionic conduction process are determined on the base of the transition state theory. It has been found that the LiAsF6 solutions in a mixed PC – DMSO solvent have a narrower electrochemical window compared to the solutions of this ionophore in pure PC and DMSO solvents.
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Chauhan, Mohinder S., Kishore C. Sharma, Girish Kumar, and Suvarcha Chauhan. "Conductance and Viscosity Studies of Ion Solvation in Mixed DMSO-MeOH Solvent." Collection of Czechoslovak Chemical Communications 67, no. 8 (2002): 1141–53. http://dx.doi.org/10.1135/cccc20021141.
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Solvation behavior of Li+, Na+, K+, Ag+, Cl-, Br-, I- and ClO4- ions is reported at 25 °C from conductance and viscosity measurements of LiClO4, NaClO4, KClO4, AgClO4, LiCl, Bu4NClO4, Bu4NBr, Bu4NI, Ph4PBPh4, Bu4NBPh4, NaBPh4, Ph4PBr and NaBr in mixed DMSO-MeOH solvent. Anomalous behavior of Ag+ is interpreted as resulting from specific ion-solvent interactions. However, Li+, Na+ and K+ interact preferentially with DMSO electrostatically through oxygen atom of SO group. Initial decrease in solvation of alkali metal ions on addition of MeOH to pure DMSO is interpreted as an indication of strong intermolecular interactions between solvent components preferably through the hydrogen bond formation. The region of relatively strong intermolecular interactions is found between 10 and 40 mole % MeOH. The viscosity studies imply the existence of interactions between Br- or I- and DMSO. The studies however, indicate poor solvation of anions in this solvent system.
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Wang, Li, Rui Xu, Ruohua Liu, Peng Ge, Wei Sun, and Mengjie Tian. "Self-Assembly of NaOL-DDA Mixtures in Aqueous Solution: A Molecular Dynamics Simulation Study." Molecules 26, no. 23 (November 24, 2021): 7117. http://dx.doi.org/10.3390/molecules26237117.
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The self-assembly behaviors of sodium oleate (NaOL), dodecylamine (DDA), and their mixtures in aqueous solution were systematically investigated by large-scale molecular dynamics simulations, respectively. The interaction mechanisms between the surfactants, as well as the surfactants and solvent, were revealed via the radial distribution function (RDF), cluster size, solvent-accessible surface area (SASA), hydrogen bond, and non-bond interaction energy. Results showed that the molecules more easily formed aggregates in mixed systems compared to pure systems, indicating higher surface activity. The SASA values of DDA and NaOL decreased significantly after mixing, indicating a tighter aggregation of the mixed surfactants. The RDF results indicated that DDA and NaOL strongly interacted with each other, especially in the mixed system with a 1:1 molar ratio. Compared to van der Waals interactions, electrostatic interactions between the surfactant molecules were the main contributors to the improved aggregation in the mixed systems. Besides, hydrogen bonds were found between NaOL and DDA in the mixed systems. Therefore, the aggregates in the mixed systems were much more compact in comparison with pure systems, which contributed to the reduction of the repulsive force between same molecules. These findings indicated that the mixed NaOL/DDA surfactants had a great potential in application of mineral flotation.
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Aliwarga, Lienda, Herri Susanto, Reynard Reynard, and Agnes Veronica Victoria. "UNIFAC Model for Liquid-Liquid Phase Equilibrium of Penicillin G and 6-APA System." Jurnal Kimia Valensi 5, no. 2 (November 30, 2019): 185–93. http://dx.doi.org/10.15408/jkv.v5i2.9869.
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This study investigated the effect of pH and type of solvent on liquid-liquid phase equilibrium in the system of pure penicillin G and mixed penicillin G with 6-APA. Penicillin G extraction was carried out in a pH range of 2.0–5.0 at 4 oC using several types of solvents. The liquid-liquid phase equilibrium mathematical model is prepared assuming that a single stage of thermodynamic equilibrium occurs in a batch process of liquid-liquid extraction. The coefficient of activity was calculated by the UNIFAC method. From the experiment, it was found that the extraction process of penicillin G was strongly influenced by pH of the solution. The highest yield of extraction was achieved with different solvents in the two types of solution. For pure penicillin G system, the highest yields was obtained in n-butyl acetate solvent (95.51%) while for penicillin G mixture with 6-APA, it was obtained in methyl iso-butyl ketone solvent (92.6%). The UNIFAC model have been tested against five three-component liquid-liquid phase equilibrium systems at pH 2.0 and 2.5. It was able to estimate the concentration of penicillin G in the organic phase with a relatively average error between experiment and calculation of 8.32%
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Mehta, Dhruvi R., Raviprakash S. Chandra, and M. M. Maisuria. "Thermodynamic Studies of Complexes of Amlodipine Besylate with Ni2+, Mg2+, Co2+ and Ca2+ cations in pure and in mixed binary solvent systems at 303.15, 313.15 and 323.15 K by Conductometric Method." International Journal of ChemTech Research 13, no. 1 (2020): 206–16. http://dx.doi.org/10.20902/ijctr.2019.130125.
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The present work relates to the complexation reaction between Amlodipine Besylate[AML] with Ni2+, Mg2+, Co2+ and Ca2+ cation in dimethylsulfoxide (DMSO), pure methanol (MeOH) and their binary mixtures(DMSO-MeOH and DMSO-Water) by conductometric method. The conductance data show that the stoichiometry of the complexes formed between AML with Ni2+, Mg2+, Co2+ and Ca2+ cation in pure DMSO, pure MeOHas well as in the binary solvent mixtures was 1:1. The stability of AML complexes with Ni2+ , Mg2+, Co2+ and Ca2+ metal ion was observed to be sensitive to the nature of the solvent system. In case of DMSO-Water binary solvent systems there was a linear change in LogKf values but in case of DMSO-MeOH binary solvent systems non linear change in LogKf values observed.The negative values of ΔG0 show that the reaction is spontaneous and ability of the AML ligand to form stable complexes. However, the result shows positive value of ΔH0 which indicates that enthalpy is not driving force for the formation of the complexes. Furthermore, the positive value of ΔS0 indicates that entropy is a driving force for the complexation. The values of ΔH0 and ΔS0 for formation of the complexes were obtained from temperature dependence of the stability constants.
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Li, Ke, Huiyu Yang, Lang Jiang, Xin Liu, Peng Lang, Bo Deng, Na Li, and Weilin Xu. "Glycerin/NaOH Aqueous Solution as a Green Solvent System for Dissolution of Cellulose." Polymers 12, no. 8 (August 3, 2020): 1735. http://dx.doi.org/10.3390/polym12081735.
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Dissolving cellulose in water-based green solvent systems is highly desired for further industrial applications. The green solvent glycerin—which contains hydrogen-bonding acceptors—was used together with NaOH and water to dissolve cellulose. This mixed aqueous solution of NaOH and glycerin was employed as the new green solvent system for three celluloses with different degree of polymerization. FTIR (Fourier-transform infrared), XRD (X-ray diffractometer) and TGA (thermogravimetric analysis) were used to characterize the difference between cellulose before and after regenerated by HCl. A UbbeloHde viscometer was used to measure the molecule weight of three different kinds of cellulose with the polymerization degree of 550, 600 and 1120. This solvent system is useful to dissolve cellulose with averaged molecule weight up to 2.08 × 105 g/mol.
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Gaile, Alexander A., Sofia D. Usanova, and Nadezhda S. Baranova. "EXTRACTION OF ARENES AND HETEROATOMIC COMPOUNDS FROM n-UNDECAN BY BIEXTRAGENT N-METHYLPYRROLIDONE-ETHYLENE GLYCOL." Bulletin of the Saint Petersburg State Institute of Technology (Technical University) 58 (2021): 22–26. http://dx.doi.org/10.36807/1998-9849-2020-58-84-22-26.
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The results of the extraction of thiophene, dibenzothiophene, diphenylamine, indole, carbazole, fluoranthene and pyrene from model mixtures with n-undecane, as well as thiophene from a mixture with n-heptane at a content of the extractable component in the binary system of 10% wt. are presented. A mixed solvent N-methylpyrrolidone - ethylene glycol with the composition of 90/10% wt. at 25 °C was used for the extraction. The experimental data obtained were compared with the results of the extraction of the same components from model mixtures with n-undecane by pure N-methylpyrrolidone
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Fosbøl, Philip L., Kaj Thomsen, and Erling H. Stenby. "Solubility Measurements in the Mixed Solvent Electrolyte System Na2CO3−NaHCO3−Monoethylene Glycol−Water." Industrial & Engineering Chemistry Research 48, no. 4 (February 18, 2009): 2218–28. http://dx.doi.org/10.1021/ie8011648.
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Chen, Dan, Binglin Li, Bin Li, Xiaoli Zhang, Longhui Wei, and Wenwen Zheng. "Synthesis of vitamin E succinate catalyzed by nano-SiO2 immobilized DMAP derivative in mixed solvent system." Green Processing and Synthesis 8, no. 1 (January 28, 2019): 667–76. http://dx.doi.org/10.1515/gps-2019-0037.
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Abstract Catalytic efficiency in synthesis of vitamin E succinate was dramatically increased via the preparation of robust catalyst and the improvement of reaction system. 4-dimethylaminopyridine (DMAP) was covalently immobilized on nano-SiO2 to avoid the catalyst contamination of the product and permit the easy recycling of DMAP. Then, a hexane-acetone mixed solvent system was firstly introduced to replace the traditional single-solvent system, which was employed to improve the activity of immobilized DMAP derivative and the substrate solubility of the reaction system. The highest vitamin E succinate yield of 94% was achieved. In addition, the recyclability and stability of the immobilized DMAP derivative was excellent, the yield of vitamin E succinate had no obvious loss and remained 90% after recycling 20 times. The excellent results make this technology be a promising candidate for the industrial production of vitamin E succinate.
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Islam, Nayyer, Muhammad Irfan, Salah-Ud-Din Khan, Haroon Khalid Syed, Muhammad Shahid Iqbal, Ikram Ullah Khan, Amina Mahdy, et al. "Poloxamer-188 and d-α-Tocopheryl Polyethylene Glycol Succinate (TPGS-1000) Mixed Micelles Integrated Orodispersible Sublingual Films to Improve Oral Bioavailability of Ebastine; In Vitro and In Vivo Characterization." Pharmaceutics 13, no. 1 (January 4, 2021): 54. http://dx.doi.org/10.3390/pharmaceutics13010054.
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Orodispersible sublingual films (OSFs) composed of hydrophilic polymers were loaded with poloxamer-188 and d-α-tocopheryl polyethylene glycol succinate (TPGS-1000) mixed micelles to improve the oral bioavailability of a poorly soluble drug, ebastine (EBT). Mixed micelles formed by thin-film hydration method were incorporated into orodispersible sublingual film, consisting of HPMC and glycerol, using solvent casting technique. The mixed micelles and films were thoroughly evaluated for physicochemical characterization (size, polydispersity index, zeta potential, entrapment efficiency, thickness, weight, surface pH studies, disintegration time, swelling indices, mechanical properties, FTIR, PXRD, DSC, SEM, AFM, in vitro drug release, in vivo bioavailability, and toxicological studies). The results showed that the average particle size of mixed micelles was 73 nm. The mean zeta potential and PDI of the optimal mixed micelles formulation were −26 mV and 0.16, respectively. Furthermore, the maximum entrapment efficiency 82% was attained. The film’s disintegration time was in the range of 28 to 102 s in aqueous media. The integrity of micelles was not affected upon incorporation in films. Importantly, the micelles-loaded films revealed rapid absorption, high permeability, and increased bioavailability of EBT as compared to the pure drug. The existence of ebastine loaded mixed micelles in the films enhanced the bioavailability about 2.18 folds as compared to pure drug. Further, the results evidently established in-vitro and in-vivo performance of bioavailability enhancement, biocompatibility, and good safety profile of micelles-loaded orodispersible EBT films. Finally, it was concluded that film loaded with poloxamer-188/TPGS-1000 mixed micelles could be an effective carrier system for enhancing the bioavailability of ebastine.
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Li, Penghui, Guimin Zhang, Zongyi Zhou, Ying Sun, Yan Wang, Yu Yang, and Xiaolai Zhang. "The Effect of Solvents on the Crystal Morphology of Isosorbide Mononitrate and Its Molecular Mechanisms." Molecules 29, no. 2 (January 11, 2024): 367. http://dx.doi.org/10.3390/molecules29020367.
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In this work, the modified attachment energy model was used to predict the crystal morphology of isosorbide mononitrate (ISMN) in the dichloromethane (CH2Cl2) solvent system and dichloromethane-n-hexane (CH2Cl2-C6H14) mixed solvent system. The solvent effect can significantly affect the crystal morphology, which can profoundly impact both the drug’s physicochemical properties and the subsequent technological treatment process. In addition, the interactions between solvent molecules and crystal faces were investigated using molecular dynamics simulation, and radial distribution function (RDF) analysis was performed to determine the types of interactions. The structural parameter S was introduced to characterize the roughness of each crystal surface; the change in the CH2Cl2 diffusion coefficient before and after the addition of C6H14 was analyzed using mean square displacement (MSD). The calculation results of the modified attachment energy from the two solvent systems revealed that C6H14 could accelerate crystal growth, while the crystal morphology was not greatly affected, which is of some significance as a guide for the industrial crystallization process.
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Ahmed, Abubakar S., Murtala Ahmed, and Aliyu Bello. "Molecular Dynamics Simulation Study of the Diffusion of Carbon Dioxide in Heptane: Application in Natural Gas Cleaning." Journal of Chemical Engineering and Industrial Biotechnology 9, no. 2 (December 30, 2023): 48–57. http://dx.doi.org/10.15282/jceib.v9i2.9495.
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Using solvents to remove carbon dioxide is an effective way to purify natural gas. Diffusion of solute in solvent is key to natural gas purification. In this study, molecular dynamics (MD) simulations of the diffusion of carbon dioxide in heptane at different temperatures and pressures were performed to simulate the conditions of industrial purification process. The diffusion coefficients were measured in two different configurations; pure solvent and binary solute-solvent systems. The diffusion coefficients of the binary system were observed to be in the order of 10-9 m2/s. An increased temperature was observed to increase the diffusion coefficient of the carbon dioxide in heptane while an increase in pressure reduced the value of the diffusion coefficient. The diffusion coefficient was also observed to follow an Arrhenius-type relationship with respect to temperature. The activation energy of the system increased from 9.228 kJ/mol to 11.139 kJ/mol with pressure increase. A linear relationship was detected between the diffusion coefficient and the viscosity of the system and an increased viscosity of the system results in a decreased diffusion coefficient. The results of the research showed that carbon dioxide behavior in heptane offers the theoretical backing for the development of a new natural gas desulphurization solvent.
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Bhange, Manjusha, and Amrapali Jadhav. "Formulation and Development of Novel Matrix Dispersion System based on Phospholipid Complex for Improving Oral Bioavailability of Ferulic Acid." INTERNATIONAL JOURNAL OF DRUG DELIVERY TECHNOLOGY 12, no. 04 (December 25, 2022): 1489–95. http://dx.doi.org/10.25258/ijddt.12.4.01.
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The usage of phospholipid complexes is one of the greatest ways to increase the oral poorly absorbed plant parts’ bioavailability components. However, the stickiness of due to the phospholipids, the inefficient breakdown of medications. To make the ferulic acid phospholipid complex (FAPLC) more dispersible and to create a dispersion of a matrix of ferulic acid according to the phospholipid complex (MD-FAPLC) utilizing a solvent evaporation method, pentaerythritol was used in this study. Pentaerythritol, phospholipid, and ferulic acid were mixed in a 1:2:5 ratio. Penta erythritol is used to enhance dissolving and as a dispersion agent. The study done on fourier-transform infrared spectroscopy (FTIR) and calorimetry that uses differential scanning (DSC) investigations of the ferulic acid in MD-FAPC. The solubilities of ferulic acid in water and N-octanol were significantly higher in MD-FAPC than in pure ferulic acid (FA). At 120 minutes, MD-cumulative FAPLC’s dissolution was more than that of FA and FAPC and greater than that of pure FA. The story MD -FAPLC increased the oral bioavailability of FA by enhancing its permeability and solubility while maintaining its complex state with phospholipids.
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Hopper, Marvin L., and Jerry W. King. "Enhanced Supercritical Fluid Carbon Dioxide Extraction of Pesticides from Foods using Pelletized Diatomaceous Earth." Journal of AOAC INTERNATIONAL 74, no. 4 (July 1, 1991): 661–66. http://dx.doi.org/10.1093/jaoac/74.4.661.
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Abstract Supercritical fluid carbon dioxide (SC-C02), when used with an extraction enhancer, comprises a supercritical fluid extraction (SFE) system for extraction of pesticides and matrix components from fatty and nonfatty foods. After being mixed with the enhancer, samples ranging from 95 % water to pure lipophilic oils can be extracted efficiently with SC-C02. This extraction technique yields analyte recoveries in excess of 85 % for over 30 types of pesticides at incurred levels ranging from 0.005 to 2 ppm in such diverse matrixes as carrots, lettuce, peanut butter, hamburger, and fortified butter fat and fortified potatoes. SC-C02 provides a solvent medium that is nontoxic, nonflammable, and inexpensive while also eliminating the use and disposal of potentially carcinogenic organic solvents.
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Park, D. H., M. Laivenieks, M. V. Guettler, M. K. Jain, and J. G. Zeikus. "Microbial Utilization of Electrically Reduced Neutral Red as the Sole Electron Donor for Growth and Metabolite Production." Applied and Environmental Microbiology 65, no. 7 (July 1, 1999): 2912–17. http://dx.doi.org/10.1128/aem.65.7.2912-2917.1999.
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ABSTRACT Electrically reduced neutral red (NR) served as the sole source of reducing power for growth and metabolism of pure and mixed cultures of H2-consuming bacteria in a novel electrochemical bioreactor system. NR was continuously reduced by the cathodic potential (−1.5 V) generated from an electric current (0.3 to 1.0 mA), and it was subsequently oxidized by Actinobacillus succinogenes or by mixed methanogenic cultures. The A. succinogenes mutant strain FZ-6 did not grow on fumarate alone unless electrically reduced NR or hydrogen was present as the electron donor for succinate production. The mutant strain, unlike the wild type, lacked pyruvate formate lyase and formate dehydrogenase. Electrically reduced NR also replaced hydrogen as the sole electron donor source for growth and production of methane from CO2. These results show that both pure and mixed cultures can function as electrochemical devices when electrically generated reducing power can be used to drive metabolism. The potential utility of utilizing electrical reducing power in enhancing industrial fermentations or biotransformation processes is discussed.
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Mullins, Eric, Y. A. Liu, Adel Ghaderi, and Stephen D. Fast. "Sigma Profile Database for Predicting Solid Solubility in Pure and Mixed Solvent Mixtures for Organic Pharmacological Compounds with COSMO-Based Thermodynamic Methods." Industrial & Engineering Chemistry Research 47, no. 5 (March 2008): 1707–25. http://dx.doi.org/10.1021/ie0711022.
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Khanam, Zakia, Farook Adam, Ompal Singh, and Jamal Ahmad. "A novel acylated flavonoidic glycoside from the wood of cultivated Acacia nilotica (L.) Willd. Ex. Delile." BioResources 6, no. 3 (June 21, 2011): 2932–40. http://dx.doi.org/10.15376/biores.6.3.2932-2940.
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Acacia is a fast-growing plant that has high potential in commercial plantations in tropical areas. It is already being grown as a plantation crop for building and industrial raw materials, as well as for reforestation of difficult sites. Extensive cultivation of this promising tree would enrich the natural resources besides being useful for industrial raw material, waste land management, and afforestation. In addition, Acacia exhibits extensive medicinal values. In view of the medicinal importance of Acacia nilotica and the therapeutic utility of flavonoids, an attempt has been made to isolate novel flavonoids from the wood of cultivated A. nilotica. The extraction of crude ethanol extract from the A. nilotica wood was followed by fractionation with chloroform, ethyl acetate, and methanol in increasing order of polarity of the solvent. The mixed ethyl acetate and methanol extract afforded three pure compounds through column chromtomatography and fractional crystallization. Among the isolated phenolic compounds, a new acylated flavonoidic glycoside, tricin-4′-O-β-(6′′-hydroxycinnamic)-glucoside (1) was isolated from the wood of A. nilotica together with two known compounds, gallic acid and apigenin. Their structures were established by chemical evidence, spectroscopic techniques (FT-IR, 1H-NMR, 13C-NMR, HSQC, HMBC, and ESI-MS), and by comparison with already existing spectroscopic data. The yield of novel tricin glucoside showed that it make up to 0.0786% of mixed ethyl acetate and acetone extract.
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Colpa, Dana I., Wen Zhou, Jan Pier Wempe, Jelmer Tamis, Marc C. A. Stuart, Janneke Krooneman, and Gert-Jan W. Euverink. "Thauera aminoaromatica MZ1T Identified as a Polyhydroxyalkanoate-Producing Bacterium within a Mixed Microbial Consortium." Bioengineering 7, no. 1 (February 21, 2020): 19. http://dx.doi.org/10.3390/bioengineering7010019.
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Polyhydroxyalkanoates (PHAs) form a highly promising class of bioplastics for the transition from fossil fuel-based plastics to bio-renewable and biodegradable plastics. Mixed microbial consortia (MMC) are known to be able to produce PHAs from organic waste streams. Knowledge of key-microbes and their characteristics in PHA-producing consortia is necessary for further process optimization and direction towards synthesis of specific types of PHAs. In this study, a PHA-producing mixed microbial consortium (MMC) from an industrial pilot plant was characterized and further enriched on acetate in a laboratory-scale selector with a working volume of 5 L. 16S-rDNA microbiological population analysis of both the industrial pilot plant and the 5 L selector revealed that the most dominant species within the population is Thauera aminoaromatica MZ1T, a Gram-negative beta-proteobacterium belonging to the order of the Rhodocyclales. The relative abundance of this Thauera species increased from 24 to 40% after two months of enrichment in the selector-system, indicating a competitive advantage, possibly due to the storage of a reserve material such as PHA. First experiments with T. aminoaromatica MZ1T showed multiple intracellular granules when grown in pure culture on a growth medium with a C:N ratio of 10:1 and acetate as a carbon source. Nuclear magnetic resonance (NMR) analyses upon extraction of PHA from the pure culture confirmed polyhydroxybutyrate production by T. aminoaromatica MZ1T.
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Said, Nur Rahimah, Majid Rezayi, Ninie Suhana Abdul Manan, Amirhossein Sahebkar, and Yatimah Alias. "Analysis of complexation between new bidentate bis-NHC ligand and some metal cations at different temperature." Analytical Methods in Environmental Chemistry Journal 5 (June 28, 2022): 5–23. http://dx.doi.org/10.24200/amecj.v5.i02.169.
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In this research, the determination and complexation process between 3,3'-(2,2'-(4-methyl-phenylenesulfonamido)bis(ethane-2,1-diyl))bis(1-benzyl-3H-benzo[d]imidazol-1-ium)dibromide with Ni2+, Zn2+, Pd2+, Ag+, and Hg2+ cations in the binary mixture of methanol (MeOH) and water (H2O) at different temperatures (15, 25, 35 and 45ºC) were studied using a conductometric method. The results show that the stoichiometry of the complexes in all binary mixed solvents for Ni2+, Zn2+, and Pd2+ were 1:1 (M:L), while in other cases 1:2 (M:L) and 2:1(M:L). The stability constants (log ) of complex formation have been determined by fitting molar conductivity curves using a computer program (GENPLOT). The obtained data shows that in the pure methanol solvent system, the stability order is Ni2+< Pd2+<Zn2+<Hg2+<Ag+ and the complexation process seems more stable in pure methanol in most cases. The thermodynamic parameters were determined conductometrically. The complexes in all cases were found to be enthalpy destabilized but entropy stabilized. The experimental data was tested by using an artificial neural network (ANN) program and was in good agreement with the estimated data.
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Abdullah Ali, Hezha, and Hunar Kamal Omer. "Solubility Enhancement of a Poorly Water-Soluble Drug Using Hydrotropy and Mixed Hydrotropy-Based Solid Dispersion Techniques." Advances in Pharmacological and Pharmaceutical Sciences 2022 (November 28, 2022): 1–16. http://dx.doi.org/10.1155/2022/7161660.
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Purpose. The biopharmaceutics classification system places rosuvastatin calcium in class II has a low and fluctuating oral bioavailability. The research focus is to maximize rosuvastatin calcium solubility in water and dissolution rate by employing and combining various hydrotropic agents to make a solid dispersion using solvent evaporation techniques. Methodology. The experimental study was conducted at Duhok University, College of Pharmacy. Initially, assess rosuvastatin’s solubility in hydrotropic agents including urea, mannitol, citric acid, sodium benzoate, and sodium salicylate at concentrations of 10, 20, 30, and 40% w/v. Then, various ratios of 2 and 3 hydrotropic agents were employed to reduce the concentration of each hydrotropic agent. By using a solvent evaporation procedure, solid dispersions were made. The solid dispersion powders underwent evaluation for their percentage drug content, percentage yield, solubility, dissolution test, XRD, DSC, SEM, and FTIR. For statistical analysis, GraphPad InStat Demo software was used to conduct a two-way analysis of variance (ANOVA). Results. In comparison to the pure drug, the solubility of hydrotropic solid dispersions and physical mixtures of rosuvastatin with a combination of hydrotropic agents (sodium salicylate, sodium benzoate, and urea) in the ratio of 13.33 for each increased in all formulations significantly, and all manufactured formulations’ drug release ranged from 98.83 to 104.78%, indicating a noticeably higher dissolution rate. Conclusion. The concept of mixed hydrotropic solid dispersion was shown to be an original, risk-free, and cost-effective method for enhancing the bioavailability of drugs that have a low degree of solubility in water.
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Jung, Eunyoung, Choon-Sang Park, Taeeun Hong, and Heung-Sik Tae. "Structure and Dielectric Properties of Poly(vinylidenefluoride-co-trifluoroethylene) Copolymer Thin Films Using Atmospheric Pressure Plasma Deposition for Piezoelectric Nanogenerator." Nanomaterials 13, no. 10 (May 22, 2023): 1698. http://dx.doi.org/10.3390/nano13101698.
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This study investigates the structural phase and dielectric properties of poly(vinylidenefluoride-co-trifluoroethylene) (P[VDF–TrFE]) thin films grown via atmospheric pressure (AP) plasma deposition using a mixed polymer solution comprising P[VDF–TrFE] polymer nano powder and dimethylformamide (DMF) liquid solvent. The length of the glass guide tube of the AP plasma deposition system is an important parameter in producing intense cloud-like plasma from the vaporization of DMF liquid solvent containing polymer nano powder. This intense cloud-like plasma for polymer deposition is observed in a glass guide tube of length 80 mm greater than the conventional case, thus uniformly depositing the P[VDF–TrFE] thin film with a thickness of 3 μm. The P[VDF–TrFE] thin films with excellent β-phase structural properties were coated under the optimum conditions at room temperature for 1 h. However, the P[VDF–TrFE] thin film had a very high DMF solvent component. The post-heating treatment was then performed on a hotplate in air for 3 h at post-heating temperatures of 140 °C, 160 °C, and 180 °C to remove DMF solvent and obtain pure piezoelectric P[VDF–TrFE] thin films. The optimal conditions for removing the DMF solvent while maintaining the β phases were also examined. The post-heated P[VDF–TrFE] thin films at 160 °C had a smooth surface with nanoparticles and crystalline peaks of β phases, as confirmed by the Fourier transform infrared spectroscopy and XRD analysis. The dielectric constant of the post-heated P[VDF–TrFE] thin film was measured to be 30 using an impedance analyzer at 10 kHz and is expected to be applied to electronic devices such as low-frequency piezoelectric nanogenerators.
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Shulzhenko, Sergii. "GENERATION UNIT COMMITMENT MIXED INTEGER LINEAR MODEL FOR SIMULTANEOUS HEAT AND ELECTRIC DAILY LOAD COVERING." System Research in Energy 2023, no. 1 (April 7, 2023): 25–34. http://dx.doi.org/10.15407/srenergy2023.01.025.
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The unit commitment problem nowadays is widely used in the electric power sector. The problem was first time formulated in the 1940-s and still developing both methodologically and by including an additional number of technologies each of which has a different unique mathematical treatment corresponding to the specific technology's behavior. The common characteristic of the problem such as that is dedicated to the electricity production sector, hence the mathematical formulation is following pure electricity sector transformation but during the last years the Power-to-X technologies are implemented and their further development is expected in the future. This requires the advancement or at least modification of the problem formulation to meet possible exchange and usage between different types of energy within one integrated power system. The goal of the article is to further development of the existing versions of the unit commitment problem, which are dedicated to the operation of the generation in the power system by implementing additional equations allowing contemplation of the heat energy-producing technologies which are dedicated to cover a heat-energy load of the district heating systems. This should allow for conducting comprehensive studies of the simultaneous operation of electric- and heat-generating technologies to meet the energy demand of local energy systems, which is important for designing distributed generation mix, for example at a municipal level. The proposed mixed integer linear generation unit commitment model for simultaneous heat and electric daily load covering is described in the article. The proposed model in addition to the pure electric power balance also meets heat load using only-heat technologies (fuel boilers), combined heat and power units, and also industrial-scale electric boilers - which are converting electricity to heat energy. Keywords: mixed integer linear model, unit commitment problem, integrated power system, electric boilers, power-to-X technologies, conventional electricity generating technologies.
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Su, Hui, Zheng Li, Jian Zhang, Zhaowu Zhu, Lina Wang, and Tao Qi. "Recovery of lithium from salt lake brine using a mixed ternary solvent extraction system consisting of TBP, FeCl3 and P507." Hydrometallurgy 197 (November 2020): 105487. http://dx.doi.org/10.1016/j.hydromet.2020.105487.
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Shua'ab, Abbas Khalaf Mohammed. "Drag Reducing Flow of water in forced closed loop circulation system by using Sodium dodecyl sulfate additive." Kufa Journal of Engineering 4, no. 1 (January 30, 2014): 97–112. http://dx.doi.org/10.30572/2018/kje/411254.
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The turbulent flow friction of a water solution with a small amount of surfactant additive is dramatically reduced when compared to that of pure water. This effect offers a significant reduction in pumping power and energy consumption. Commercial implementation of drag reducing fluids have proved successful for oil pipeline transportation, district heating and cooling systems, fire fighting, sewer throughput, jet cutting, etc. The investigation was carried out on a facility with a forced closed loop for pressure drop measurements. A type of anionic surfactant (Sodium dodecyl sulfate) mixed with same weight of counter ion material (Sodium nitrate) was used as a drag reducing additive to tap water at a mass concentration ranged from 50 to 2000 ppm. Pressure drop data was collected over a 1668 mm flow pipe of carbon steel with 15.8 and 26.6 mm internal diameter and different solution flow rate (up to 8 m3/h) at constant temperature of 30 ̊C (ambient temperature). The paper focused on calculation of friction factor from experimental data. It was found that the friction factor values lies near Blasuis asymptote for pure solvent, while they positioned towards maximum drag reduction asymptotes when surfactant is added. A maximum drag reduction percent of about 66% was obtained by using 2000 ppm surfactant – counter ion aqueous solution. Also, it was concluded that there is a critical Reynolds number equals to about 96000 not to be exceeded because any further increasing leads to decrease in drag reduction. In addition, a correlation equation was found to correlate wall shear stress as a function of bulk mean fluid velocity. This correlation equation is of value in scale up of results obtained in small laboratory equipments to larger diameter pipes and different operating conditions. Another objective was to investigate the mechanism behind a possible drag reduction.
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Pandey, Aditi, Tzu-Sen Yang, Shu-Lien Cheng, Ching-Shuan Huang, Agnese Brangule, Aivaras Kareiva, and Jen-Chang Yang. "A Novel One-Pot Synthesis and Characterization of Silk Fibroin/α-Calcium Sulfate Hemihydrate for Bone Regeneration." Polymers 13, no. 12 (June 18, 2021): 1996. http://dx.doi.org/10.3390/polym13121996.
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This study aims to fabricate silk fibroin/calcium sulfate (SF/CS) composites by one-pot synthesis for bone regeneration applications. The SF was harvested from degummed silkworm cocoons, dissolved in a solvent system comprising of calcium chloride:ethanol:water (1:2:8), and then mixed with a stoichiometric amount of sodium sulfate to prepare various SF/CS composites. The crystal pattern, glass transition temperature, and chemical composition of SF/CS samples were analyzed by XRD, DSC, and FTIR, respectively. These characterizations revealed the successful synthesis of pure calcium sulfate dihydrate (CSD) and calcium sulfate hemihydrate (CSH) when it was combined with SF. The thermal analysis through DSC indicated molecular-level interaction between the SF and CS. The FTIR deconvolution spectra demonstrated an increment in the β-sheet content by increasing CS content in the composites. The investigation into the morphology of the composites using SEM revealed the formation of plate-like dihydrate in the pure CS sample, while rod-like structures of α-CSH surrounded by SF in the composites were observed. The compressive strength of the hydrated 10 and 20% SF-incorporated CSH composites portrayed more than a twofold enhancement (statistically significant) in comparison to that of the pure CS samples. Reduced compressive strength was observed upon further increasing the SF content, possibly due to SF agglomeration that restricted its uniform distribution. Therefore, the one-pot synthesized SF/CS composites demonstrated suitable chemical, thermal, and morphological properties. However, additional biological analysis of its potential use as bone substitutes is required.
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Satapathy, Bhabani, Asuprita Patel, Rudra Sahoo, and Subrata Mallick. "Crystal products of lamotrigine-citric acid for improvement of in vitro drug release in simulated gastric fluid." Journal of the Serbian Chemical Society, no. 00 (2020): 49. http://dx.doi.org/10.2298/jsc200705049s.
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Crystal engineering is an integral part of the drug development research. Crystal forms can modify the physicochemical properties of the parent drug molecule. The present work was aimed at the synthesis and characterization of crystalline product of lamotrigine (LT), a FDA approved anti-epileptic drug, with citric acid (CA) to improve its release in gastric region and oral absorption. The crystalline products of LT-CA were developed by solvent evaporation method using ethanol-water as the solvent system. Appearance of new charac-teristic peaks in the FTIR spectra for the crystal products indicated formation of new crystal state. In DSC thermogram, melting point of the experimental crystal products was different than that of the pure drug. Further, formation of new crystalline phase was confirmed from XRD data through the identification of new sharp peaks for the selected crystal products. A higher cumulative percen-tage of drug release was observed for the crystal products than the free drug within 60 min of drug release in simulated gastric fluid. However, in vivo studies are warranted for the future technology transfer of the product at industrial scale.
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Huang, Zhongyuan, Xuliang Jin, Xuefeng Zhao, Fanqin Meng, and Aiming Yin. "Industrial test of post combustion CO2 capture by reactive absorption with two new solvents in natural gas power plant." E3S Web of Conferences 520 (2024): 02024. http://dx.doi.org/10.1051/e3sconf/202452002024.
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The post-combustion chemical decarbonization process is one of the key technology selections for the low-carbon development of natural gas power plants. The high energy consumption of amine regeneration is hindering its commercial application. In this paper, two new mixed amines solvent 15%Diethylaminoethanol (DEEA) +9% Piperazine (PZ)+ 6% Monoethanolamine (MEA) named DT01-3 and 22% 1,4-butanediamine (BDA)+ 4% N-Methyldiethanolamine (MDEA) + 4% 2-Amino-2-methyl-1-propanol (AMP) named DT02-2 are verified by the 3000Nm3/h industrial demonstration system. The steady state condition was gradually established by adjusting the main parameters such as flue gas flow rate, absorber inlet flue gas temperature, solvent circulation flow rate, regeneration tower operation pressure, steam flow rate and so on with the goal of maintaining ≥90% of the capture efficiency. The results show that the CO2 capture efficiency of DT01-3 and DT02-2 is 91.23% and 90.81% respectively. The regeneration heat consumption is 3.65 GJ/tCO2 and 3.73 GJ/tCO2. The amines consumption is 0.95kg/tCO2,1.1kg/tCO2. The operating cost of DT01-3 and DT02-2 is 336.37 CNY/t,346.04 CNY/t, which is 20.94%,18.68% lower compared with MEA.
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Emami, Samira, and Mir Mohammad Alavi Nikje. "Environmentally benign chemical recycling of polycarbonate wastes: comparison of micro- and nano-TiO2 solid support efficiencies." Green Processing and Synthesis 8, no. 1 (January 28, 2019): 108–17. http://dx.doi.org/10.1515/gps-2018-0028.
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Abstract Polycarbonate (PC) wastes, including optical discs (CDs) and digital optical discs (DVDs), were chemically recycled into valuable materials such as 4,4′-(propane-2,2-diyl)diphenol (BPA) and etherified derivatives of BPA using sodium hydroxide (NaOH) as the alkali metal catalyst and nanostructured titanium dioxide (nano-TiO2) and microstructured titanium dioxide (micro-TiO2) as the solid supports in the binary green system consisting of water and 2,2′-oxydi(ethan-1-ol) (DEG) under conventional heating method, and data were compared. In this study, the effects of various parameters, such as solvent composition, concentration of NaOH, and solid support, were studied on the reaction progress. In these reactions, the importance of water as the green solvent was investigated in achieving pure BPA as the valuable material. When used with 20% aqueous DEG (pbw), a pure BPA can be obtained at 70% yield in the presence of nano-TiO2 and micro-TiO2 as the solid supports. According to the results, the use of nano-TiO2 in comparison with micro-TiO2 accelerates the chemical recycling of PC wastes. The nano-TiO2 catalyst recovery shows that the recovered solid support is applicable for four cycles. The obtained products were characterized using spectroscopic methods, namely, 1H NMR, 13C NMR, and Fourier transform infrared spectroscopy as well as gas chromatography-mass spectrometry.
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Couture, Lorraine, Jacques E. Desnoyers, and Gérald Perron. "Some thermodynamic and transport properties of lithium salts in mixed aprotic solvents and the effect of water on such properties." Canadian Journal of Chemistry 74, no. 2 (February 1, 1996): 153–64. http://dx.doi.org/10.1139/v96-019.
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In a continuing study on the optimization of the electrolyte medium for high-energy lithium batteries, volumes, heat capacities, and specific conductivities of LiClO4 and LiBr were measured in mixtures of γ-butyrolactone (BUTY) and 1,2-dimethoxyethane (DME) and of propylene carbonate (PC) and BUTY. These results are compared with those of the electrolytes in the pure solvents. Phase diagrams are also reported when appropriate. The effect of addition of water to these binary and ternary systems was investigated with the same techniques. The mixtures DME–BUTY, PC–DME, DME–H2O, and BUTY–H2O are typical of mixtures of aprotic solvents and mixtures of aprotic solvents and water. The electrolytes at high concentrations in aprotic solvents of low dielectric constants are largely associated. The medium still conducts electrolytically since the ion pairs are in a state that resembles to a large extent that of a molten salt. With some systems at high concentration, stable solvates persist in the solution medium, as evidenced mostly by heat capacities, and are in equilibrium with either the excess solvent or unsolvated molten salts. In mixed solvents, the properties of electrolytes can largely be predicted from the binary systems and by the coexistence of these solvates. The properties of water in DME, BUTY, or mixtures of the two solvents are modified significantly in the presence of LiBr but only slightly with LiClO4. These specific interactions, which affect the heat capacities much more than the volumes and which are especially large with the system LiBr–DME, could be responsible for the decrease in reactivity of water with lithium metal in an aprotic medium in the presence of certain electrolytes. Key words: LiClO4, LiBr, γ-butyrolactone, dimethoxyethane, propylene carbonate, lithium battery, aprotic solvent, water, association, solvates, solid–liquid phase diagrams, volumes, heat capacities, specific conductivities.
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Talla, Gangadharudu, Soumya Gangopadhyay, and CK Biswas. "Effect of impregnated powder materials on surface integrity aspects of Inconel 625 during electrical discharge machining." Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 232, no. 7 (September 2, 2016): 1259–72. http://dx.doi.org/10.1177/0954405416666904.
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In recent times, nickel-based super alloys are widely utilized in aviation, processing, and marine industries owing to their supreme ability to retain the mechanical properties at elevated temperature in combination with remarkable resistance to corrosion. Some of the properties of these alloys such as low thermal conductivity, strain hardening tendency, chemical affinity, and presence of hard and abrasives phases in the microstructure render these materials very difficult-to-cut using conventional machining processes. In this work, an experimental setup was developed and integrated with the existing electrical discharge machining system for carrying out powder-mixed electrical discharge machining process for Inconel 625. The experiments were planned and conducted by varying five different variables, that is, powder concentration, peak current, pulse-on time, duty cycle, and gap voltage based on the central composite design of response surface methodology. Effects of these parameters along with powder concentration were investigated on various surface integrity aspects including surface morphology, surface roughness, surface microhardness, change in the composition of the machined surface, and residual stress. Results clearly indicated that addition of powder to dielectric has significantly improved surface integrity compared to pure dielectric. Among the powders used, silicon has resulted in highest microhardness, that is, almost 14% more than graphite. Lowest surface roughness (approximately 50% less than pure kerosene) and least residual stress were obtained using silicon powder (approximately 8% less than graphite-mixed dielectric). Relative content of nickel was reduced at the expense of Nb and Mo after addition of powders like aluminum and graphite in dielectric during electrical discharge machining.
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McIntyre, J. C., P. Hundley, and W. D. Behnke. "The role of aromatic side chain residues in micelle binding by pancreatic colipase. Fluorescence studies of the porcine and equine proteins." Biochemical Journal 245, no. 3 (August 1, 1987): 821–29. http://dx.doi.org/10.1042/bj2450821.
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Fluorescence techniques have been employed to study the interaction of porcine and equine colipase with pure taurodeoxycholate and mixed micelles. Nitrotyrosine-55 of porcine colipase is obtained by modification with tetranitromethane (low excess, in the presence of taurodeoxycholate) of the protein followed by gel filtration and ion-exchange chromatography. Verification of the residue modified was obtained by h.p.l.c. peptide purification and sequence analysis. Reduction and quantitative reaction with dansyl chloride yields a fluorescent derivative that is twice as active in conjunction with lipase as is native colipase and that exhibits a strong emission band at 550 nm. Addition of micellar concentrations of taurodeoxycholate causes a 4.3-fold increase in the emission maximum as well as a 70 nm blue shift to 480 nm. Inclusion of oleic acid to form a mixed micelle reduces these spectral effects. Scatchard analysis of the data yield a Kd of 6.8 × 10(-4) M and a single colipase-binding site for taurodeoxycholate micelles. The data, by analogy to a phospholipase system, are consistent with a direct insertion of dansyl-NH-tyrosine-55 into the micelle. The presence of a single tryptophan residue (Trp-52) in equine colipase provides an intrinsic fluorescent probe for studying protein-micelle interaction. The emission maximum of horse colipase at 345 nm indicates a solvent-accessible tryptophan residue which becomes less so on binding of micelles. A blue shift of 8 nm and a 2-fold increase in amplitude is indicative of a more hydrophobic environment for tryptophan induced by taurodeoxycholate micelles. There is also a decrease in KSV for acrylamide quenching in the presence of micelles, which further supports a loss of solvent accessibility. The most dramatic pH effects are observed with KI quenching, and may indicate the presence of negative charges near Trp-52.
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Joshi, Shubham, Vinay Midha, and Subbiyan Rajendran. "Investigation of Durable Bio-polymeric Antimicrobial Finishes to Chemically Modified Textile Fabrics Using Solvent Induction System." TEKSTILEC 64, no. 1 (January 14, 2021): 55–69. http://dx.doi.org/10.14502/tekstilec2021.64.55-69.
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New technologies and materials required for developing antibacterial textiles have become a subject of inter¬est to the researchers in recent years. This study focuses on the investigation of the biopolymeric antibacterial agents, such as neem, aloe vera, tulsi and grapeseed oil, in the trichloroacetic acid-methylene chloride (TCAMC) solvent used for the pretreatment of polyethylene terephthalate (PET) polyester fabrics. Different PET structures, such as 100% polyester, polyester/viscose, polyester/cotton and 100% texturised, are treated with four different concentrations (5%, 10%, 15% and 20%) of biopolymeric antibacterial finishes. The antibacterial activity of the treated samples is tested against both the Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative) bacteria. Taguchi mixed orthogonal array Design L16 (4^3 2^2) is chosen for an experimental plan to determine the optimum conditions. Among all the fabric samples, the 100% polyester fabric treated with 20% grapeseed oil registers the highest antibacterial activity of 86%, and 73% against S. aureus and E. coli respec¬tively. However, the antibacterial effect is reduced to 37%, and 34% respectively after 10 machine launderings.
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Li, Liangchuan, Ming Zhou, Long Jin, Youtang Mo, Enyong Xu, Huajin Chen, Lincong Liu, Mingyue Wang, Xin Chen, and Hongwei Zhu. "Green Preparation of Aqueous Graphene Dispersion and Study on Its Dispersion Stability." Materials 13, no. 18 (September 14, 2020): 4069. http://dx.doi.org/10.3390/ma13184069.
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The large-scale preparation of stable graphene aqueous dispersion has been a challenge in the theoretical research and industrial applications of graphene. This study determined the suitable exfoliation agent for overcoming the van der Waals force between the layers of expanded graphite sheets using the liquid-phase exfoliation method on the basis of surface energy theory to prepare a single layer of graphene. To evenly and stably disperse graphene in pure water, the dispersants were selected based on Hansen solubility parameters, namely, hydrophilicity, heterocyclic structure and easy combinative features. The graphene exfoliation grade and the dispersion stability, number of layers and defect density in the dispersion were analysed under Tyndall phenomenon using volume sedimentation method, zeta potential analysis, scanning electron microscopy, Raman spectroscopy and atomic force microscopy characterization. Subsequently, the long-chain quaternary ammonium salt cationic surfactant octadecyltrimethylammonium chloride (0.3 wt.%) was electrolyzed in pure water to form ammonium ions, which promoted hydrogen bonding in the remaining oxygen-containing groups on the surface of the stripped graphene. Forming the electrostatic steric hindrance effect to achieve the stable dispersion of graphene in water can exfoliate a minimum of eight layers of graphene nanosheets; the average number of layers was less than 14. The 0.1 wt.% (sodium dodecylbenzene sulfonate: melamine = 1:1) mixed system forms π–π interaction and hydrogen bonding with graphene in pure water, which allow the stable dispersion of graphene for 22 days without sedimentation. The findings can be beneficial for the large-scale preparation of waterborne graphene in industrial applications.
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Onyemenonu, C. C., E. C. Nleonu, C. Onuguh, and A. U. Ezeibe. "Volumetric Behaviour of Binary Mixture of Dual Purpose Kerosene (DPK) and Automotive Gas Oil (AGO) at 303K." Science View Journal 4, no. 3 (December 20, 2023): 348–52. http://dx.doi.org/10.55989/eqbt7954.
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The study of volume changes in binary mixtures is attracting considerable interest from researchers due to the degree of molecular interaction between the mixed solvent molecules and their importance in many chemical industries and engineering disciplines. The experimental values of densities (ρ) and viscosities (η) of pure and binary mixtures of dual-purpose kerosene (DPK) and automotive gas oil (AGO) were obtained over the whole range of mixture composition at a temperature of 303 K. The experimental data obtained were employed to determine the excess molar volume (V_m^E), excess viscosity (VE), and excess Gibb’s free energy of activation (ΔGE) based on the molecular interactions arising due to the structural effect of the mixture. The measured viscosity values were correlated with Grunberg and Nissan, Kendel and Monroe, and Frenkel’s semi-empirical models to evaluate the best fit for the system. The results acquired were explained according to their structural differences, strength, and nature of intermolecular interactions in the binary mixture. The experimental result revealed that the binary mixture of DPK and AGO shows positive excess molar volume and negative excess viscosity. Weak, specific interactions were responsible for the dispersion force in the binary mixtures.
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Jiao, Jinqing, Tao Li, Guangwen Zhang, Jing Xiong, Xuqing Lang, Xiaolong Quan, Yiwei Cheng, and Yuechang Wei. "Molecular Dynamics Simulations of the Short-Chain Fluorocarbon Surfactant PFHXA and the Anionic Surfactant SDS at the Air/Water Interface." Molecules 29, no. 7 (April 3, 2024): 1606. http://dx.doi.org/10.3390/molecules29071606.
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The research and development of alternatives to long-chain fluorocarbon surfactants are desperately needed because they are extremely toxic, difficult to break down, seriously harm the environment, and limit the use of conventional aqueous film-forming foam fire extinguishing agents. In this study, mixed surfactant systems containing the short-chain fluorocarbon surfactant perfluorohexanoic acid (PFHXA) and the hydrocarbon surfactant sodium dodecyl sulfate (SDS) were investigated by molecular dynamics simulation to investigate the microscopic properties at the air/water interface at different molar ratios. Some representative parameters, such as surface tension, degree of order, density distribution, radial distribution function, number of hydrogen bonds, and solvent-accessible surface area, were calculated. Molecular dynamics simulations show that compared with a single type of surfactant, mixtures of surfactants provide superior performance in improving the interfacial properties of the gas–liquid interface. A dense monolayer film is formed by the strong synergistic impact of the two surfactants. Compared to the pure SDS system, the addition of PFHXA caused SDS to be more vertically oriented at the air/water interface with a reduced tilt angle, and a more ordered structure of the mixed surfactants was observed. Hydrogen bonding between SDS headgroups and water molecules is enhanced with the increasing PFHXA. The surface activity is arranged in the following order: PFHXA/SDS = 1:1 > PFHXA/SDS = 3:1 > PFHXA/SDS = 1:3. These results indicate that a degree of synergistic relationship exists between PFHXA and SDS at the air/water interface.
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Carpenter, Chris. "Robust Scale Dissolver Mitigates Mixed-Scale Issue in South China Sea." Journal of Petroleum Technology 75, no. 11 (November 1, 2023): 88–90. http://dx.doi.org/10.2118/1123-0088-jpt.
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_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 211187, “Tackling Mixed-Scales Issue in an Oil Field Using a Novel Robust Scale Dissolver,” by Nora Aida Ramly, Luky Hendraningrat, SPE, and Latief Riyanto, SPE, Petronas, et al. The paper has not been peer reviewed. _ The evaluation of a recently developed robust solid dissolver (RSD), from the laboratory phase through pilot deployment, is presented in the complete paper. Based on laboratory tests, the RSD can dissolve mixed scales completely in 24 hours at well temperatures while experiencing no incompatibility issues with production chemicals and all pumping and wireline components. The RSD was developed based on the total organic system that can prevent corrosion and is compatible with hydrocarbon. The RSD was piloted at oil Well 1 in Field PN and successfully removed mixed scales, allowing the well’s revival. Introduction Solid scale deposition is one of the most frequent flow-assurance issues both in subsurface and at the surface. The scale can be classified as organic (wax or asphaltenes), inorganic (calcites, sulphates, sulfides, halites, carbonates, and oxides), soap-related (naphthenates and carboxylates), gas-related (hydrates), or mixed scales. Scale occurrence, quantity, and severity mainly are determined by mineralogy, water chemistry, reservoir pressure and temperature, and the flow characteristics of the producing fluid in the well. Furthermore, scale formation is exacerbated by higher pH conditions and a higher water-cut environment, as would be expected in oil fields where water is to be injected for pressure maintenance. The most common type of scales found in Malaysian oil fields are organic and inorganic scales. The operator’s previously deployed scale-dissolving chemical in its fields only could cater to a single type of scale treatment at a time, which was ineffective for dissolving mixed scales simultaneously. Another method is the use of a mechanical solution using a coiled tubing unit (CTU). Removal mechanically by CTU in tubulars is a successful method in removing hard barite scales, but the cost is high and the method requires several days of production deferment. An improved and cheaper mixed-scale removal approach was needed to clean out mixed-scale issues in more-challenging brownfields. The RSD technology was developed for wellbore cleanout caused by mixed scale based on a stable microemulsion solution consisting of acid and solvent components. The solution was proposed to dissolve both organic and inorganic scales simultaneously in the near-wellbore area and tubing string of an oil well. The very small droplet size formed by the surfactant system and solvent is a significant advantage of using microemulsion and can allow penetration even in tight formations with small pore throats and promotes more-uniform surface coverage because of the increased interfacial area of the droplets. Previous studies have reported that the microemulsion can be pumped without causing a significant increase in pumping pressure.
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Harvianto, Gregorius Rionugroho, Ki Joon Kang, and Moonyong Lee. "Process Design and Optimization of an Acetic Acid Recovery System in Terephthalic Acid Production via Hybrid Extraction–Distillation Using a Novel Mixed Solvent." Industrial & Engineering Chemistry Research 56, no. 8 (February 17, 2017): 2168–76. http://dx.doi.org/10.1021/acs.iecr.6b04586.
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Jain, Stuti A., and Nalini S. Kurup. "Formulation of Irbesartan by Microcrystal Technology for Enhancing the Solubility and Dissolution Properties." International Journal of Pharmaceutical Sciences and Nanotechnology 6, no. 2 (August 31, 2013): 2064–76. http://dx.doi.org/10.37285/ijpsn.2013.6.2.9.
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The aim of this study was to develop the formulation of irbesartan by microcrystal technology to enhance the solubility and dissolution property of the drug. The area of interest in the study carried out is Class II drugs cited in the Biopharmaceutical Classification System. Microcrystal technology is a new carrier-free colloidal drug delivery system with reduced drug particle size and is considered a viable strategy in drug delivery to develop formulations of poorly soluble drugs. In the present study, an attempt was made to enhance the solubility of the drug irbesartan compared to its pure form by microcrystal technology. Drug microcrystals were prepared by the anti-solvent precipitation process. The specified amount of drug was dissolved in methanol and PVP K30 was dissolved in water. The two phases were mixed instantaneously, wherein the drug solution was kept on continuous stirring and the aqueous phase was added to this continuous phase. The particle size of the drug was not reduced, but enhancement in solubility and dissolution properties of the drug were still observed. This could be due to the wettability property of PVP K30. The FT-IR spectra and DSC thermograms confirmed no interference of drug and the stabilizer. XRD studies confirmed the formation of crystals of the drug irbesartan. Thus, it could be concluded that microcrystal technology is a promising approach for solubility enhancement of irbesartan.
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Kaushal, Deepika, Dilbag S. Rana, Manish Kumar, Kailash Singh, Kuldeep Singh, Suvarcha Chauhan, and Ahmad Umar. "Furosemide–Cetyltrimethylammonium Bromide Interactions in Aqueous Dimethylsulfoxide Solutions: Physico–Chemical Studies." Zeitschrift für Physikalische Chemie 233, no. 3 (March 26, 2019): 413–30. http://dx.doi.org/10.1515/zpch-2017-1014.
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Abstract Interaction of a cardiovascular drug, Furosemide with cetyltrimethylammonium bromide (CTAB) has been studied in aqueous solutions of Dimethylsulfoxide (DMSO) with the help of density, speed of sound and conductivity measurements over a range of temperatures 293.15–313.15 K at interval of 5 K. The interaction parameters viz. apparent molar volume, Vϕ and apparent molar isentropic compression, κs,ϕ have been enumerated from density and speed of sound data. Also, variation in the micellization behavior has been explored by calculating critical micelle concentration, CMC. It has been observed that micellization tendency of the surfactant decreases in the presence of DMSO as compared to pure aqueous system. Moreover, the CMC values shift toward lower concentration with increase in Furosemide content because of increase in hydrophobic hydration which may be to hydrophobicity of drug molecule. The dependence of CMC in mole fraction (Xcmc) values on the temperature has been analyzed in terms of thermodynamics of the system by reporting the standard thermodynamic parameters i.e. standard Gibb’s free energy $(\Delta G_m^o),$ enthalpy $(\Delta H_m^o)$ and entropy $(\Delta S_m^o)$ of micellization for CTAB in mixed solvent systems. The entropies of micellization are all positive, and they compensate the enthalpies of the process. Compensation temperature, Tc has also been evaluated from enthalpy–entropy compensation whose values lies in Lumrys range (270–300 K).
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Lee, Kyung Won, Jin Ku Cho, Chulhwan Park, and Baek-Jin Kim. "Step-by-Step Hybrid Conversion of Glucose to 5-acetoxymethyl-2-furfural Using Immobilized Enzymes and Cation Exchange Resin." Processes 10, no. 10 (October 14, 2022): 2086. http://dx.doi.org/10.3390/pr10102086.
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An alternative to 5-hydroxymethyl-2-furfural (HMF), which is a promising furan derivative that can be used as a starting material for the preparation of non-petroleum-derived polymeric materials from sugars, is 5-acetoxymethyl-2-furfural (AMF). The less-hydrophilic acetyl group of AMF has advantages over the hydroxy group of HMF in terms of thermal stability and isolation. In previous studies, fructose has been used as a starting material along with lipases for the enzymatic synthesis of AMF. In this study, we designed a hybrid synthesis system that includes the isomerization and esterification of glucose into AMF. For the step-by-step conversion of glucose to 1,6-diacetylfructose (DAF), glucose-isomerase and immobilized lipase (Novozym 435) were used as enzymes. Furthermore, for the synthesis of AMF, the direct dehydration of DAF was performed using a cation exchange resin (Amberlyst 15), combined with several industrial solvents, such as dimethylsulfoxide (DMSO), acetonitrile (AN) and dimethylformamide (DMF) for the synthesis of AMF. In order to improve the final yield of AMF, we determined the best solvent conditions. While the AMF yield after the direct dehydration of DAF in a single solvent was maximum 24%, an AMF and HMF yield in the mixed solvent such as dioxane and DMS (9:1) was achieved each 65% and 15%. According to these results, we found that the addition of dioxane in aprotic polar solvents could affect the dehydration reaction and dramatically improve the formation of AMF and HMF.
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Slefarski, Rafal, Pawel Czyzewski, and Michal Golebiewski. "Experimental study on combustion of CH4/NH3 fuel blends in an industrial furnace operated in flameless conditions." Thermal Science 24, no. 6 Part A (2020): 3625–35. http://dx.doi.org/10.2298/tsci200401282s.
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This paper presents the results of an experimental study on the combustion process of methane mixed with NH3 in flameless mode. At a time of striving for CO2-free power, NH3 became a potential energy storage carrier fuel from renewable sources. Flameless combustion features low emissions and is a very efficient technology used in the power sector, as well as steel production, ceramics, etc. Industrial furnaces were tested in the context of pure methane combustion with an addition of NH3, up to 5%. Flameless combustion conditions were achieved with a regenerative gas burner system (high regenerative system). The burner consists of four ceramic regenerators allowing for continuous preheating of air, even up to 50 K lower than the temperature of the combustion chamber wall. Constant power of the introduced fuel was kept at 150 kW and the fuel-air equivalence ratio ranged from 0.75 to 0.95. The results have shown a growth of molar fraction of NO in flue gases when NH3 content in the fuel rose. The increase is more significant for the tests with a higher amount of oxygen in the combustion chamber (a lower fuel-air equivalence ratio). An addition of 5% of NH3 into the fuel caused an emission of NO at the levels of 113 ppmv and 462 ppmv (calculated to O2 = 0%), respectively for low and high fuel-air equivalence ratios.
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Treyer, Andrea, Jakob K. Reinhardt, Daniela Elisabeth Eigenmann, Mouhssin Oufir, and Matthias Hamburger. "Phytochemical Comparison of Medicinal Cannabis Extracts and Study of Their CYP-Mediated Interactions with Coumarinic Oral Anticoagulants." Medical Cannabis and Cannabinoids 6, no. 1 (February 8, 2023): 21–31. http://dx.doi.org/10.1159/000528465.
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Introduction: Treatment with cannabis extracts for a variety of diseases has gained popularity. However, differences in herb-drug interaction potential of extracts from different plant sources are poorly understood. In this study, we provide a characterization of cannabis extracts prepared from four cannabis chemotypes and an in vitro assessment of their Cytochrome P450 (CYP)-mediated herb-drug interaction profiles. Methods: Plant extracts were either commercially obtained or prepared using ethanol as solvent, followed by overnight decarboxylation in a reflux condenser system. The extracts were characterized for their cannabinoid content using NMR and HPLC-PDA-ELSD-ESIMS. CYP inhibition studies with the cannabis extracts and pure cannabinoids (tetrahydrocannabinol [THC] and cannabidiol [CBD]) were performed using pooled, mixed gender human liver microsomes. Tolbutamide and testosterone were used as specific substrates to assess the inhibitory potential of the extracts on CYP2C9 and CYP3A4, and the coumarinic oral anticoagulants warfarin, phenprocoumon, and acenocoumarol were studied as model compounds since in vivo herb-drug interactions have previously been reported for this compound class. Results: In accordance with the plant chemotypes, two extracts were rich in THC and CBD (at different proportions); one extract contained mostly CBD and the other mostly cannabigerol (CBG). Residual amounts of the corresponding acids were found in all extracts. The extracts with a single major cannabinoid (CBD or CBG) inhibited CYP2C9- and CYP3A4-mediated metabolism stronger than the extracts containing both major cannabinoids (THC and CBD). The inhibition of CYP3A4 and CYP2C9 by the extract containing mostly CBD was comparable to their inhibition by pure CBD. In contrast, the inhibitory potency of extracts containing both THC and CBD did not correspond to the combined inhibitory potency of pure THC and CBD. Although being structural analogs, the three coumarin derivatives displayed major differences in their herb-drug interaction profiles with the cannabis extracts and the pure cannabinoids. Conclusion: Despite the fact that cannabinoids are the major components in ethanolic, decarboxylated cannabis extracts, it is difficult to foresee their herb-drug interaction profiles. Our in vitro data and the literature-based evidence on in vivo interactions indicate that cannabis extracts should be used cautiously when co-administered with drugs exhibiting a narrow therapeutic window, such as coumarinic anticoagulants, regardless of the cannabis chemotype used for extract preparation.
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Han, Yikuan, and Zhaoyi Wang. "Transplantation and Adaptation: Research on Reinforced Concrete Structures in Modern Nanjing (1909–1949)." Buildings 13, no. 6 (June 5, 2023): 1468. http://dx.doi.org/10.3390/buildings13061468.
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Modern Nanjing experienced a boom in the construction industry. As an advanced material and construction system, reinforced concrete structure was also imported during this period. This paper presents the brief historical background and structural adaptability of reinforced concrete buildings in modern Nanjing. Reinforced concrete was used in industrial buildings in the districts along the Yangtze River in the early 20th century, and in public buildings along Zhongshan Road after 1927. Western-style reinforced concrete buildings used both pure frame structure system and mixed structure with a reinforced concrete frame, brick masonry and timber roof trusses. The Chinese Renaissance buildings used roof structures with different shapes and materials on the main reinforced concrete structure. Based on the study of existing modern reinforced concrete buildings in Nanjing, this paper classifies and compares different types of structures, and indicates that the selection of structures was the adaptive result of comprehensive trade-offs between structural performance, space availability and economy. This research implies the transplantation and adaptation of reinforced concrete structures in modern Nanjing and lays a fundamental structural foundation for the conservation of this architectural heritage.
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Allam, Heba Khodary, Shaimaa Soliman, Tamer Wasfy, Ahmed Ghoneim, Yasser Serag, and Grace Sembajwe. "The neuro-ophthalmological effects related to long-term occupational exposure to organic solvents in painters." Toxicology and Industrial Health 34, no. 2 (November 14, 2017): 91–98. http://dx.doi.org/10.1177/0748233717736598.
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Purpose: Organic solvents are widely used in many industries, and usually, exposure occurs with mixtures of solvents. Organic solvent mixtures are known for their ability to affect tissues of high lipid content including the myelin sheath in the nervous system. The purpose of this work was to study the evidence that long-term (more than 10 years) exposure to organic solvent mixtures among painters can induce neuro-ophthalmological effects on the function of retinal ganglion cells and the optic tract. Methods: Twenty workers with long-term occupational exposure to mixed organic solvents were compared to 40 control subjects. The controls were matched for age, gender, and demographic characteristics but were not occupationally exposed to any known organic solvents, using the following comparators: visual evoked potential (VEP), electroretinogram (ERG), color vision (CV), and contrast sensitivity (CS) testing. Environmental monitoring was done in the work environment with consideration to the American Conference of Governmental Industrial Hygienists Threshold Limit Values (ACGIH-TLVs). Results: The exposed group had significantly longer latency and higher amplitude of VEP waves especially P100, higher Color Confusion Index (CCI), especially affecting the blue–yellow spectrum, and lower Log CS. There was no significant difference between exposed and nonexposed groups in full-field flash ERG response; however, in the pattern ERG, the exposed group had significantly longer latency of P50, which reflects changes in the retinal ganglion cell. Conclusion: Long-term occupational exposure to mixed organic solvents appeared to affect the optic tract functions in the form of increasing latency of VEP response, affecting the quality of CV and decreasing CS. It also affects the retinal ganglion cell layer with increased latency of P50 of the pattern ERG response.
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Zhou, Rong, Jian Wang, and Zeqi Huang. "Evolutionary Game Analysis of the Participants in the Realization of Ecological Product Value." SHS Web of Conferences 158 (2023): 01022. http://dx.doi.org/10.1051/shsconf/202315801022.
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Realizing the value of ecological products is the key point to realize the integration of the dual goals of ecological civilization construction and economic development in China, and is a powerful grip for promoting industrial transformation and upgrading and implementing high-quality development tactics. In the value realization mechanism of ecological products, it is most critical to coordinate the relationship among farmers, ecological product developers and the government. Based on the systematic analysis of the game relationship among three subjects, this study constructs a game model and uses evolutionary game and numerical simulation methods to analyze the model, obtains the conditions of pure strategy selection of three subjects and the evolutionary law of mixed strategy probability combinations. This study confirms the crowding-out effect and the effectiveness of combining incentive policies such as government subsidies, fines, and required loss compensation, providing a decision reference for building an eco-product value realization system from the perspective of organizational relationship governance and policy mechanism construction.
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Alston, R. B., G. P. Kokolis, and C. F. James. "CO2 Minimum Miscibility Pressure: A Correlation for Impure CO2 Streams and Live Oil Systems." Society of Petroleum Engineers Journal 25, no. 02 (April 1, 1985): 268–74. http://dx.doi.org/10.2118/11959-pa.
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Abstract This paper presents an empirically derived correlation for estimating the minimum pressure required for multicontact miscible (MCM) displacement of live oil systems by pure or impure CO2 streams. Minimum miscibility pressure (MMP) has been correlated with temperature, oil C5+ molecular weight, volatile oil fraction, intermediate oil fraction, and composition of the CO2 stream. The effects of temperature and oil C5+ molecular weight on pure CO2 MMP have been well documented. However, CO2 sources are rarely pure, and solution gas usually is present in reservoir oils. The correlation presented in this paper accounts for the additional effects on MMP caused by the presence of volatile components (methane, C1; and N2) and intermediate components (ethane, C2; propane, C3; butane, C4; hydrogen sulfide, H2S; and CO2) in the reservoir oil. This correlation also is capable of estimating MMP for a contaminated or enriched CO2 stream on the basis of the pure CO2 MMP. Introduction Miscible displacements using hydrocarbon solvents have been described in the literature by many authors.1–6 The use of a slim tube apparatus for the establishment of MMP requirements for enriched or vaporizing gas drives was presented by Deffrenne et al.5 and Yarborough and Smith.7 Rutherford8 referred to these systems as conditionally miscible processes. The initial work of Rathmell et al.9 and Ballard and Smith10 illustrated that the mechanisms of CO2 displacements are similar to those of high-pressure MCM vaporizing gas drives. Since the high solubility of CO2 in reservoir oils diminishes the pressure required for miscibility to occur, a CO2 vaporizing gas drive can operate in the same manner as a lean-gas injection process, but at significantly lower pressures. Correlations for the prediction of MMP requirements for CO2 flooding are extremely helpful in the screening of candidate reservoirs for CO2 floods. Holm and Josendal11 were the first to introduce a method for estimating the MMP required for CO2 displacing oil. Other correlations for CO2 MMP have been introduced by the Natl. Petroleum Council,12 Yellig and Metcalfe,13 and Johnson and Pollin,14 as well as a new correlation from Holm and Josendal.15,16 This paper presents an empirical approach to MMP estimation. Included in this study are the effects of solution gas (live oil systems) and the effects of impure CO2 sources. Concepts of Miscible Displacement Miscible displacement is represented most easily by a ternary diagram. A pseudoternary diagram for a hypothetical hydrocarbon system is shown in Fig. 1. This is a pseudoternary representation since the apexes do not consist of pure components, but it can be used to qualitatively describe the process of miscible displacement. Fig. 1 has been divided into three areas: Zone 1, Zone 2, and Zone 3. Zone 1 represents the area of first-contact miscibility. Any solvent falling within this region can be mixed with the reservoir oil shown, such that any and all mixtures will fall outside of the two-phase region. Zone 2 represents the region of multicontact miscibility. Solvents within this area, while not initially miscible in all proportions with the reservoir oil, eventually will achieve miscibility through the repeated contacts of the reservoir oil and equilibrium fluids. There are two types of MCM processes: vaporizing gas drive, where the solvent is enriched by components vaporized from the reservoir oil, and condensing or enriched gas drive, where the solvent contributes to the enrichment of the reservoir fluid.17 Commercially viable CO2-miscible EOR processes are usually of the MCM type, because reservoir pressure requirements for this process are significantly lower than required for first contact miscibility. Zone 3 represents the area of immiscible displacement. Displacement of the reservoir oil by an fluid falling within Zone 3 will result in multiphase flow. The mass transfer between the oil and displacing fluid is such that miscibility cannot be achieved.