The Experts below are selected from a list of 155940 Experts worldwide ranked by ideXlab platform
Lina Song - One of the best experts on this subject based on the ideXlab platform.
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Recovery-Based Error Estimator for Stabilized Finite Element Method for the Stationary Navier--Stokes Problem
SIAM Journal on Scientific Computing, 2016Co-Authors: Lina Song, Haiyan Su, Xinlong FengAbstract:A recovery-based error estimator is proposed and analyzed for stabilized $P_1/P_0$ (continuous Linear Velocity/constant pressure) finite element approximations to the stationary Navier--Stokes problem. We establish the reliability and efficiency of the error estimator. A crucial part of this work is the estimation for the nonLinear term of the Navier--Stokes problem. It turns out such a term can be bounded by the recovery-based error estimator. Numerical results are provided to illustrate the performance of the error estimator.
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recovery based error estimator for stabilized finite element methods for the stokes equation
Computer Methods in Applied Mechanics and Engineering, 2014Co-Authors: Lina SongAbstract:Abstract A recovery-based error estimator is proposed and analyzed for stabilized P 1 / P 0 (continuous Linear Velocity/constant pressure) finite element approximations to the Stokes equation. Reliability and efficiency of the estimator are established for various stabilized methods. For several test problems, numerical results show that our estimator is more accurate than the classical residual error estimator.
Howard A Chase - One of the best experts on this subject based on the ideXlab platform.
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single and two component cation exchange adsorption of the two pure major whey proteins
Journal of Chromatography A, 2009Co-Authors: Mayyada M H Elsayed, Howard A ChaseAbstract:Abstract Adsorption of pure α-lactalbumin (ALA) and β-lactoglobulin (BLG) to the cation exchanger SP Sepharose FF was studied at pH 3.7 with the purpose of developing a process for isolating them from whey. Measurement of Langmuir parameters describing adsorption equilibrium in batch experiments and protein breakthrough time values in 1-ml packed-beds at a Linear Velocity of 158 cm/h and initial concentrations of 3 mg/ml for BLG and 1.5 mg/ml for ALA suggested the feasibility of using this adsorbent to separate the two proteins when present in a mixture. Subsequent experiments with 5-ml columns at the above concentrations and a Linear Velocity of 30 cm/h confirmed this and showed evidence of competitive adsorption as ALA displaced and eluted all BLG from the column in a pure form, and the remaining ALA could be eluted thereafter at high purity and with 91% recovery.
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single and two component cation exchange adsorption of the two pure major whey proteins
Journal of Chromatography A, 2009Co-Authors: Mayyada M H Elsayed, Howard A ChaseAbstract:Adsorption of pure alpha-lactalbumin (ALA) and beta-lactoglobulin (BLG) to the cation exchanger SP Sepharose FF was studied at pH 3.7 with the purpose of developing a process for isolating them from whey. Measurement of Langmuir parameters describing adsorption equilibrium in batch experiments and protein breakthrough time values in 1-ml packed-beds at a Linear Velocity of 158 cm/h and initial concentrations of 3 mg/ml for BLG and 1.5 mg/ml for ALA suggested the feasibility of using this adsorbent to separate the two proteins when present in a mixture. Subsequent experiments with 5-ml columns at the above concentrations and a Linear Velocity of 30 cm/h confirmed this and showed evidence of competitive adsorption as ALA displaced and eluted all BLG from the column in a pure form, and the remaining ALA could be eluted thereafter at high purity and with 91% recovery.
Seung-hyeon Moon - One of the best experts on this subject based on the ideXlab platform.
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determination of the limiting current density in electrodialysis desalination as an empirical function of Linear Velocity
Desalination, 2006Co-Authors: Heiner Strathmann, Seung-hyeon MoonAbstract:Electrodialysis is known to be a useful membrane process for water desalination. The limiting current density (LCD) in the electrodialysis process is an important parameter which determines the electrical resistance and the current utilization. Usually, LCD depends on membrane and solution properties as well as on the electrodialysis stack construction and various operational parameters such as the flow Velocity of the diluate solution. Therefore, a reliable determination of LCD is required for designing an efficient electrodialysis plant. In this study, LCD was measured in an electrodialysis flow cell system of given geometry and spacer configuration as a function of the Linear Velocity. The coefficients a and b of an equation describing LCD as a function of the Linear flow Velocity of the diluate solution, ilim=aCub, were determined from a plot of the measured LCD over the electrolyte concentration versus the Linear Velocity on a double logarithmic scale. It was found that the coefficient b was related to the hydrodynamic conditions, while the coefficient a was affected by the cell geometry, electrolyte concentration and the membrane properties.
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determination of the limiting current density in electrodialysis desalination as an empirical function of Linear Velocity
Desalination, 2006Co-Authors: Heiner Strathmann, Seung-hyeon MoonAbstract:Electrodialysis is known to be a useful membrane process for water desalination. The limiting current density (LCD) in the electrodialysis process is an important parameter which determines the electrical resistance and the current utilization. Usually, LCD depends on membrane and solution properties as well as on the electrodialysis stack construction and various operational parameters such as the flow Velocity of the diluate solution. Therefore, a reliable determination of LCD is required for designing an efficient electrodialysis plant. In this study, LCD was measured in an electrodialysis flow cell system of given geometry and spacer configuration as a function of the Linear Velocity. The coefficients a and b of an equation describing LCD as a function of the Linear flow Velocity of the diluate solution, ilim=aCub, were determined from a plot of the measured LCD over the electrolyte concentration versus the Linear Velocity on a double logarithmic scale. It was found that the coefficient b was related to the hydrodynamic conditions, while the coefficient a was affected by the cell geometry, electrolyte concentration and the membrane properties.
Mayyada M H Elsayed - One of the best experts on this subject based on the ideXlab platform.
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single and two component cation exchange adsorption of the two pure major whey proteins
Journal of Chromatography A, 2009Co-Authors: Mayyada M H Elsayed, Howard A ChaseAbstract:Abstract Adsorption of pure α-lactalbumin (ALA) and β-lactoglobulin (BLG) to the cation exchanger SP Sepharose FF was studied at pH 3.7 with the purpose of developing a process for isolating them from whey. Measurement of Langmuir parameters describing adsorption equilibrium in batch experiments and protein breakthrough time values in 1-ml packed-beds at a Linear Velocity of 158 cm/h and initial concentrations of 3 mg/ml for BLG and 1.5 mg/ml for ALA suggested the feasibility of using this adsorbent to separate the two proteins when present in a mixture. Subsequent experiments with 5-ml columns at the above concentrations and a Linear Velocity of 30 cm/h confirmed this and showed evidence of competitive adsorption as ALA displaced and eluted all BLG from the column in a pure form, and the remaining ALA could be eluted thereafter at high purity and with 91% recovery.
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single and two component cation exchange adsorption of the two pure major whey proteins
Journal of Chromatography A, 2009Co-Authors: Mayyada M H Elsayed, Howard A ChaseAbstract:Adsorption of pure alpha-lactalbumin (ALA) and beta-lactoglobulin (BLG) to the cation exchanger SP Sepharose FF was studied at pH 3.7 with the purpose of developing a process for isolating them from whey. Measurement of Langmuir parameters describing adsorption equilibrium in batch experiments and protein breakthrough time values in 1-ml packed-beds at a Linear Velocity of 158 cm/h and initial concentrations of 3 mg/ml for BLG and 1.5 mg/ml for ALA suggested the feasibility of using this adsorbent to separate the two proteins when present in a mixture. Subsequent experiments with 5-ml columns at the above concentrations and a Linear Velocity of 30 cm/h confirmed this and showed evidence of competitive adsorption as ALA displaced and eluted all BLG from the column in a pure form, and the remaining ALA could be eluted thereafter at high purity and with 91% recovery.
Georges Guiochon - One of the best experts on this subject based on the ideXlab platform.
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performance of columns packed with the new shell kinetex c18 particles in gradient elution chromatography
Journal of Chromatography A, 2010Co-Authors: Fabrice Gritti, Georges GuiochonAbstract:The performance of columns packed with the new 2.6 microm Kinetex-C(18) shell particles was investigated in gradient elution chromatography and compared with those of the 2.7 microm Halo-C(18) shell particles and the 1.7 microm BEH-C(18) totally porous particles. The peak capacities P(c) of these columns were derived from the resolution of the components of a peptide mixture (beta-Lactoglobulin digest) and of a mixture of two biomolecules (insulin and lyzozyme).The three columns exhibit the same peak capacities for the peptides at low Linear Velocity (u(0) < 0.05 cm/s) and at any gradient steepness (0.8 < G < 10). When the Linear Velocity is increased 10-fold, the peak capacity of the Kinetex column remains nearly unchanged while those of the Halo-C(18) and the BEH-C(18) columns decrease by 20%, approximately. This result confirms the very flat HETP curve, the very low C term of the Kinetex column and its ability to successfully operate at high flow rates while experiencing less efficiency loss than other columns. Despite its smaller average mesopore size (96 A versus 130 A), the column packed with 2.6 microm shell Kinetex-C(18) particles gives an equivalent or even slightly better separation of biomolecules having a size and a mass around 40 A and 15 kDa, respectively, than the column packed with 1.7 microm BEH-C(18) totally porous particles. This result demonstrates the advantages of the shell versus the conventional particle technology when it comes to resolve mixtures of large and slow diffusive biomolecules.
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the shock layer thickness a new approach to the study of column performance in non Linear chromatography i optimum Linear Velocity in frontal analysis
Journal of Chromatography A, 1993Co-Authors: Georges Guiochon, Jie ZhuAbstract:Abstract In non-Linear chromatography, it is common to observe very steep profiles. This happens for overloaded elution bands, for frontal analysis breakthrough curves and for the band profiles of the isotachic train in displacement chromatography. These regions where the concentration vary very rapidly are called shock layers. The relationship between the thickness of the shock layer in frontal analysis and the coefficients of the conventional terms of the plate height equation were studied experimentally. The shock layer theory of Rhee and co-workers permits the simple determination of the optimum Linear Velocity for minimum shock layer thickness in the case when the adsorption behavior of the feed components is described by the Langmuir model. The optimum Linear Velocity in frontal analysis is not only a function of the coefficients of the axial dispersion and the mass transfer resistance terms, and the retention factor (k0 ) , as in Linear chromatography, but also a function of the plateau concentrations and the second Langmuir parameter of the isotherm, b. Depending on the retention factor, the optimum Velocity in frontal analysis may be larger, but is most often much smaller than in Linear chromatography. Experimental results are in excellent agreement with the prediction of the theory. If they could be extended to displacement chromatography, these findings would explain some apparent contradictions found in the literature regarding the influence of the mobile phase flow Velocity on the degree of separation between bands achieved in displacement chromatography, and clarify certain controversies.