The Experts below are selected from a list of 9123 Experts worldwide ranked by ideXlab platform
Ho-ming Yeh - One of the best experts on this subject based on the ideXlab platform.
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Recovery of deuterium from water-isotope mixture by thermal diffusion in Countercurrent-flow flat-plate Frazier scheme with optimum plate spacing
Progress in Nuclear Energy, 2010Co-Authors: Ho-ming YehAbstract:Abstract The effect of plate spacing on the degree of recovery and production rate for deuterium recovery from water–isotope mixture in flat-plate thermal diffusion columns of Countercurrent-flow Frazier scheme with fixed operation expense, has been investigated. The equations for estimating optimum plate spacing for maximum recovery and maximum production rate have been derived. Considerable improvement in performance is obtainable when thermal diffusion columns with optimum plate spacing are employed for operation. The fact that Countercurrent-flow operation is more effective than cocurrent-flow operation for the recovery of deuterium in a Frazier scheme, is also confirmed.
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deuterium recovery from water isotope mixture by thermal diffusion in Countercurrent flow frazier scheme inclined for improved performance
Fusion Engineering and Design, 2008Co-Authors: Ho-ming YehAbstract:The theory for recovery of deuterium from water isotope mixture by thermal diffusion in Countercurrent-flow inclined Frazier scheme has been developed and investigated. The equations for the optimal angles of inclination and the corresponding best performances were derived. Considerable improvement in performance is obtained when the Frazier scheme is operated at the optimal angle of inclination. Further improvement can be achieved if the operation is conducted in Countercurrent flow, instead of being in cocurrent flow.
Guillermo Reglero - One of the best experts on this subject based on the ideXlab platform.
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recovery of squalene from vegetable oil sources using Countercurrent supercritical carbon dioxide extraction
Journal of Supercritical Fluids, 2007Co-Authors: L Vazquez, Carlos F Torres, Tiziana Fornari, Javier F Senorans, Guillermo RegleroAbstract:The purification of squalene from residues of the olive oil deodorization process using Countercurrent supercritical carbon dioxide extraction was studied. The raw material employed is a by-product obtained after distillation and ethylation of olive oil deodorizer distillates. This by-product contains mainly squalene and fatty acid esters. The Group Contribution Equation of State was employed to simulate the separation process and to design the experimental extractions, which were carried out in an isothermal Countercurrent column, without reflux, at 343 K, pressures ranging from 150 to 230 bar and a solvent-to-feed ratio around 13. Satisfactory agreement was found between experimental and calculated yields and phase compositions, obtaining a raffinate product with a squalene concentration up to 90 wt.%. Finally, the thermodynamic model was employed to find out optimal process conditions to enhance squalene recovery, including partial reflux of the extract product and recirculation of the supercritical solvent in a continuous Countercurrent extraction column.
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isolation of antioxidant compounds from orange juice by using Countercurrent supercritical fluid extraction cc sfe
Journal of Agricultural and Food Chemistry, 2001Co-Authors: Francisco J Senorans, Alejandro Ruizrodriguez, Sofia Cavero, Alejandro Cifuentes, Elena Ibanez, Guillermo RegleroAbstract:Antioxidants from orange juice are isolated by the use of Countercurrent supercritical fluid extraction (CC−SFE) and characterized by reversed-phase liquid chromatography (RPLC) coupled to mass spectrometry (MS) and diode-array detection (DAD). A pilot-scale SFE plant equipped with a packed column has been employed for Countercurrent extraction and fractionation of raw orange juice with carbon dioxide. Several experiments have been performed in order to study the effect of the Countercurrent conditions on the content of antioxidative compounds. In this study, the main variable that has been considered is the solvent-to-feed ratio (S/F) because it plays an essential role in the extraction efficiency. The values tested covered a wide range of sample and solvent (CO2) flow rates. In each experimental run, two different extracted fractions and the residual nonextracted juice were obtained and characterized. Different flavonoids have been identified in the fractions obtained after CC−SFE. The possibility of us...
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optimization of Countercurrent supercritical fluid extraction conditions for spirits fractionation
Journal of Supercritical Fluids, 2001Co-Authors: Francisco J Senorans, Alejandro Ruizrodriguez, Elena Ibanez, Javier Tabera, Guillermo RegleroAbstract:Abstract Optimization of the Countercurrent supercritical fluid extraction (CC-SFE) conditions to obtain distilled alcoholic drinks extracts with low alcoholic content is presented. The optimization procedure is based on the use of an experimental design and the subsequent statistical study of the data obtained. Experiments have been performed with brandy, using a Countercurrent supercritical fluid extraction (CC-SFE) system on a pilot-plant scale. The beverage is brought directly into contact with the carbon dioxide current in a packed column, and the extracts are recovered in two different fractionation cells, where depressurization occurs. The main variables that influence Countercurrent extraction efficiency have been studied, such as sample flow rate, solvent flow rate (that is solvent-to-feed ratio) and level of sample introduction into the extraction column. Statistical data analysis indicates the variables that clearly influence the process and also the most convenient parameter values from which to obtain a high-value concentrated extract with a rich brandy aroma and low ethanol content.
Sheng-qiang Tong - One of the best experts on this subject based on the ideXlab platform.
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Chiral ligand exchange Countercurrent chromatography: Equilibrium model study on enantioseparation of mandelic acid.
Journal of chromatography. A, 2016Co-Authors: Sheng-qiang Tong, Qing Xiong, Xiaoping Wang, Mangmang Shen, Jizhong YanAbstract:The equilibrium model in enantioseparation of mandelic acid by chiral ligand exchange Countercurrent chromatography was investigated using N-n-dodecyl-l-proline as chiral ligand and cupric ion as central metal. Important parameters, including physical partition coefficient and formation constants of binary and ternary coordination complexes in the two-phase solvent system, were determined. This equilibrium model could give an excellent prediction of distribution ratio and enantioseparation factor of the analyte in the biphasic solvent system, which was further verified by experiments. All the average relative deviations were less than 12%, indicating that the established model could provide a simple computational approach for optimization of enantioseparation conditions in chiral ligand exchange Countercurrent chromatography.
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chiral ligand exchange high speed Countercurrent chromatography mechanism and application in enantioseparation of aromatic α hydroxyl acids
Journal of Chromatography A, 2014Co-Authors: Sheng-qiang Tong, Mangmang Shen, Dongping Cheng, Yamei ZhangAbstract:Abstract This work concentrates on the separation mechanism and application of chiral ligand exchange high-speed Countercurrent chromatography in enantioseparation of ten racemic aromatic α-hydroxyl acids, including mandelic acid, 2-chloromandelic acid, 4-methoxymandelic acid, 4-hydroxymandelic acid, α-methylmandelic acid, 4-hydroxy-3-methoxy-mandelic acid, 3-chloromandelic acid, 4-bromomandelic acid, α-cyclopentylmandelic acid and α-cyclohexylmandelic acid, in which five of the racemates were successfully enantioseparated by analytical apparatus with an optimized solvent system. The two-phase solvent system was composed of butanol-water (1:1, v/v) or hexane-n-butanol-water (0.5:0.5:1, v/v), to which N-n-dodecyl- l -proline was added in the organic phase as chiral ligand and cupric acetate was added in the aqueous phase as a transition metal ion. Various influence factors in high-speed Countercurrent chromatography were optimized by enantioselective liquid–liquid extraction. The separation mechanism for chiral ligand exchange high-speed Countercurrent chromatography was proposed based on the results of present studies. Successful enantioseparations of 72 mg of mandelic acid, 76 mg of 2-chloromandelic acid and 74 mg of 4-methoxymandelic acid were achieved individually with high resolution by preparative high-speed Countercurrent chromatography. The HPLC purity of all enantiomers was over 96% with the recovery in the range of 82–90% from the collected fractions.
Francisco J Senorans - One of the best experts on this subject based on the ideXlab platform.
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isolation of antioxidant compounds from orange juice by using Countercurrent supercritical fluid extraction cc sfe
Journal of Agricultural and Food Chemistry, 2001Co-Authors: Francisco J Senorans, Alejandro Ruizrodriguez, Sofia Cavero, Alejandro Cifuentes, Elena Ibanez, Guillermo RegleroAbstract:Antioxidants from orange juice are isolated by the use of Countercurrent supercritical fluid extraction (CC−SFE) and characterized by reversed-phase liquid chromatography (RPLC) coupled to mass spectrometry (MS) and diode-array detection (DAD). A pilot-scale SFE plant equipped with a packed column has been employed for Countercurrent extraction and fractionation of raw orange juice with carbon dioxide. Several experiments have been performed in order to study the effect of the Countercurrent conditions on the content of antioxidative compounds. In this study, the main variable that has been considered is the solvent-to-feed ratio (S/F) because it plays an essential role in the extraction efficiency. The values tested covered a wide range of sample and solvent (CO2) flow rates. In each experimental run, two different extracted fractions and the residual nonextracted juice were obtained and characterized. Different flavonoids have been identified in the fractions obtained after CC−SFE. The possibility of us...
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optimization of Countercurrent supercritical fluid extraction conditions for spirits fractionation
Journal of Supercritical Fluids, 2001Co-Authors: Francisco J Senorans, Alejandro Ruizrodriguez, Elena Ibanez, Javier Tabera, Guillermo RegleroAbstract:Abstract Optimization of the Countercurrent supercritical fluid extraction (CC-SFE) conditions to obtain distilled alcoholic drinks extracts with low alcoholic content is presented. The optimization procedure is based on the use of an experimental design and the subsequent statistical study of the data obtained. Experiments have been performed with brandy, using a Countercurrent supercritical fluid extraction (CC-SFE) system on a pilot-plant scale. The beverage is brought directly into contact with the carbon dioxide current in a packed column, and the extracts are recovered in two different fractionation cells, where depressurization occurs. The main variables that influence Countercurrent extraction efficiency have been studied, such as sample flow rate, solvent flow rate (that is solvent-to-feed ratio) and level of sample introduction into the extraction column. Statistical data analysis indicates the variables that clearly influence the process and also the most convenient parameter values from which to obtain a high-value concentrated extract with a rich brandy aroma and low ethanol content.
Akio Tomiyama - One of the best experts on this subject based on the ideXlab platform.
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numerical simulation of Countercurrent gas liquid flow in a pwr hot leg under reflux cooling
Journal of Nuclear Science and Technology, 2010Co-Authors: Ikuo Kinoshita, Michio Murase, Yoichi Utanohara, Noritoshi Minami, Akio TomiyamaAbstract:In reflux cooling, the steam generated in the reactor core and the water condensed in a steam generator form a Countercurrent flow in a hot leg. In order to investigate flow patterns in the hot leg under Countercurrent flow conditions, Countercurrent air-water tests were previously conducted using a 1/15th scale model of a PWR hot leg. Numerical simulation results for the tests using a three-dimensional twofluid model in FLUENT6.3.26, implemented with an appropriate set of correlations for the gas-liquid interfacial friction, were in good agreement with the measured data. In the present study, further numerical simulations were carried out for a full-scale hot leg under PWR plant conditions to investigate the effects of pipe diameter and fluid properties. The predicted Countercurrent flow limitation characteristics were well correlated with the Wallis parameters and agreed well with the measured data from the 1/15th scale air-water tests as well as the full-scale steam-water UPTF tests. The results indica...
