scholarly journals Analysis of CO2 Facilitation Transport Effect through a Hybrid Poly(Allyl Amine) Membrane: Pathways for Further Improvement

Membranes ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 367
Author(s):  
Bouchra Belaissaoui ◽  
Elsa Lasseuguette ◽  
Saravanan Janakiram ◽  
Liyuan Deng ◽  
Maria-Chiara Ferrari
Keyword(s):  
Facilitated Transport ◽  
Transport Parameters ◽  
Material Synthesis ◽  
Transport Models ◽  
Transport Modelling ◽  
Selective Layer ◽  
Membrane Performance ◽  
A Value ◽  
Partial Pressures ◽  
Good Agreement

Numerous studies have been reported on CO2 facilitated transport membrane synthesis, but few works have dealt with the interaction between material synthesis and transport modelling aspects for optimization purposes. In this work, a hybrid fixed-site carrier membrane was prepared using polyallylamine with 10 wt% polyvinyl alcohol and 0.2 wt% graphene oxide. The membrane was tested using the feed gases with different relative humidity and at different CO2 partial pressures. Selected facilitated transport models reported in the literature were used to fit the experimental data with good agreement. The key dimensionless facilitated transport parameters were obtained from the modelling and data fitting. Based on the values of these parameters, it was shown that the diffusion of the amine-CO2 reaction product was the rate-controlling step of the overall CO2 transport through the membrane. It was shown theoretically that by decreasing the membrane selective layer thickness below the actual value of 1 µm to a value of 0.1 µm, a CO2 permeance as high as 2500 GPU can be attained while maintaining the selectivity at a value of about 19. Furthermore, improving the carrier concentration by a factor of two might shift the performances above the Robeson upper bound. These potential paths for membrane performance improvement have to be confirmed by targeted experimental work.

Prediction of Nanofiltration Performance by Using Membrane Transport Models for the Separation of Nickel Salts from Aqueous Solutions

2008 ◽  
Vol 3 (1) ◽  
Author(s):  
Alka G. Boricha ◽  
ZVP Murthy
Keyword(s):  
Membrane Transport ◽  
Film Theory ◽  
Nickel Sulfate ◽  
Nickel Chloride ◽  
Enrichment Factors ◽  
Transport Parameters ◽  
Transport Models ◽  
Membrane Performance ◽  
Polyether Sulfone ◽  
Chloride Water

Nanofiltration (NF) is considered to be an intermediate process between reverse osmosis (RO) and ultrafiltration (UF). In the present work, separation data obtained for nickel sulfate-water and nickel chloride-water systems, using an N, O-carboxymethyl chitosan (NOCC)-polyether sulfone (PES) composite NF membrane, are analyzed with the help of two nonlinear membrane transport models, viz., combined film theory-solution-diffusion (CFSD) model and combined film theory-Spiegler-Kedem (CFSK) model. The membrane transport parameters and mass transfer coefficient (k) are estimated, simultaneously, from both the models using the Levenberg-Marquardt method. The k values estimated from two models show a variation that may be attributed to the presence of reflection coefficient in the Spiegler-Kedem model. Though both the models predict the membrane performance reasonably, the values of CFSK model are more accurate in the present case. Hence, it can be suggested that CFSK model may be the better method for estimating the membrane transport parameters and k. Various parameters estimated from the above models are used to find the enrichment factors, concentration polarization modulus and Peclet numbers for both the systems.

Dynamic Gas Transport in Porous Bidispersed Alumina

1998 ◽  
Vol 63 (11) ◽  
pp. 1954-1962
Author(s):  
Vladimír Hejtmánek ◽  
Pavel Čapek ◽  
Olga Šolcová ◽  
Petr Schneider
Keyword(s):  
Optimization Algorithm ◽  
Inert Gases ◽  
Dusty Gas ◽  
Diffusion Cell ◽  
Transport Parameters ◽  
Transport Models ◽  
The Mean ◽  
Temporary Rise ◽  
Experimental Pressure ◽  
Good Agreement

A spontaneous temporary rise in the pressure gradient through countercurrent binary transport of inert gases in porous bidispersed alumina was observed in diffusion cell of the Wicke-Kallenbach type. Experimental pressure responses to gas step changes were detected and fitted to a set of partial differential equations. These were based on the transport models Mean Transport Pore Model (MTPM) and Dusty Gas Model (DGM). The dynamic set transport parameters 〈r〉, 〈r2〉 and ψ for both models were obtained using an optimization algorithm and discussed. It was found that the values of the transport radius 〈r〉 are in a good agreement with the mean radius obtained from the measurement of alumina texture.

Standardisation of von Willebrand Factor in Therapeutic Concentrates: Calibration of the 1st International Standard for von Willebrand Factor Concentrate (00/514)

2002 ◽  
Vol 88 (09) ◽  
pp. 380-386 ◽  
Author(s):  
Dawn Sands ◽  
Andrew Chang ◽  
Claudine Mazurier ◽  
Anthony Hubbard
Keyword(s):  
Von Willebrand Factor ◽  
International Study ◽  
Expert Committee ◽  
International Standard ◽  
A Value ◽  
Significant Difference ◽  
Factor Concentrate ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Good Agreement

SummaryAn international study involving 26 laboratories assayed two candidate von Willebrand Factor (VWF) concentrates (B and C) for VWF:Antigen (VWF:Ag), VWF:Ristocetin Cofactor (VWF:RCo) and VWF:Collagen binding (VWF:CB) relative to the 4th International Standard Factor VIII/VWF Plasma (4th IS Plasma) (97/586). Estimates of VWF:Ag showed good agreement between different methods, for both candidates, and the overall combined means were 11.01 IU/ml with inter-laboratory variability (GCV) of 10.9% for candidate B and 14.01 IU/ml (GCV 11.8%) for candidate C. Estimates of VWF:RCo showed no significant difference between methods for both candidates and gave overall means of 9.38 IU/ml (GCV 23.7%) for candidate B and 10.19 IU/ml (GCV 24.4%) for candidate C. Prior to the calibration of the candidates for VWF:CB it was necessary to calibrate the 4th IS Plasma relative to local frozen normal plasma pools; there was good agreement between different collagen reagents and an overall mean of 0.83 IU per ampoule (GCV 11.8%) was assigned. In contrast, estimates of VWF:CB in both candidates showed large differences between collagen reagents with inter-laboratory GCV’s of 40%. Candidate B (00/514) was established as the 1st International Standard von Willebrand Factor Concentrate by the WHO Expert Committee on Biological Standardisation in November 2001 with assigned values for VWF:Ag (11.0 IU/ampoule) and VWF:RCo (9.4 IU/ampoule). Large inter-laboratory variability of estimates precluded the assignment of a value for VWF:CB.

Heat-flow experiments in liquid 4He with a variable cylindrical geometry

1987 ◽  
Vol 174 ◽  
pp. 209-231 ◽  
Author(s):  
H. Gao ◽  
G. Metcalfe ◽  
T. Jung ◽  
R. P. Behringer
Keyword(s):  
Cylindrical Geometry ◽  
Small Scale ◽  
Onset Of Convection ◽  
Aspect Ratios ◽  
A Value ◽  
Prandtl Numbers ◽  
Convection Rolls ◽  
Flow Experiments ◽  
Increasing Function ◽  
Good Agreement

This paper first describes an apparatus for measuring the Nusselt number N versus the Rayleigh number R of convecting normal liquid 4He layers. The most important feature of the apparatus is its ability to provide layers of different heights d, and hence different aspect ratios [Gcy ]. The horizontal cross-section of each layer is circular, and [Gcy ] is defined by [Gcy ] = D/2d where D is the diameter of the layer. We report results for 2.4 [les ] [Gcy ] [les ] 16 and for Prandtl numbers Pr spanning 0.5 [lsim ] Pr [lsim ] 0.9 These results are presented in terms of the slope N1 = RcdN/dR evaluated just above the onset of convection at Rc. We find that N1 is only a slowly increasing function of [Gcy ] in the range 6 [lsim ] [Gcy ] [lsim ] 16, and that it has a value there which is quite close to 0.72. This value of N1 is in good agreement with variational calcuations by Ahlers et al. (1981) pertinent to parallel convection rolls in cylindrical geometry. Particularly for [Gcy ] [lsim ] 6, we find additional small-scale structure in N1 associated with changes in the number of convection rolls with changing [Gcy ]. An additional test of the linearzied hydrodynamics is given by measurements of Rc. We find good agreement between theory and our data for Rc.

Device Modeling of a-Si:H Alloy Solar Cells: Calibration Procedure for Determination of Model Input Parameters

1998 ◽  
Vol 507 ◽  
Author(s):  
M. Zeman ◽  
R.A.C.M.M. Van Swaaij ◽  
E. Schroten ◽  
L.L.A. Vosteen ◽  
J.W. Metselaar
Keyword(s):  
Solar Cell ◽  
Material Properties ◽  
Calibration Procedure ◽  
Model Parameters ◽  
Model Input ◽  
A Value ◽  
Input Parameters ◽  
Simulated Material ◽  
Good Agreement

ABSTRACTA calibration procedure for determining the model input parameters of standard a-Si:H layers, which comprise a single junction a-Si:H solar cell, is presented. The calibration procedure consists of: i) deposition of the separate layers, ii) measurement of the material properties, iii) fitting the model parameters to match the measured properties, iv) simulation of test devices and comparison with experimental results. The inverse modeling procedure was used to extract values of the most influential model parameters by fitting the simulated material properties to the measured ones. In case of doped layers the extracted values of the characteristic energies of exponentially decaying tail states are much higher than the values reported in literature. Using the extracted values of model parameters a good agreement between the measured and calculated characteristics of a reference solar cell was reached. The presented procedure could not solve directly an important issue concerning a value of the mobility gap in a-Si:H alloys.

scholarly journals A Monte-Carlo Simulation of the Behaviour of Electron Swarms in Hydrogen Using an Anisotropic Scattering Model

1978 ◽  
Vol 31 (4) ◽  
pp. 299 ◽  
Author(s):  
HA Blevin ◽  
J Fletcher ◽  
SR Hunter
Keyword(s):  
Experimental Data ◽  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Electron Transport ◽  
Anisotropic Scattering ◽  
Isotropic Scattering ◽  
Transport Parameters ◽  
Simulation Code ◽  
Scattering Model ◽  
Good Agreement

Hunter (1977) found that a Monte-Carlo simulation of electron swarms in hydrogen, based on an isotropic scattering model, produced discrepancies between the predicted and measured electron transport parameters. The present paper shows that, with an anisotropic scattering model, good agreement is obtained between the predicted and experimental data. The simulation code is used here to calculate various parameters which are not directly measurable.

Low frequency acoustic thermometry in the range 4.2–20 K with implications for the value of the gas constant

1979 ◽  
Vol 365 (1722) ◽  
pp. 349-370 ◽  
Keyword(s):  
Low Frequency ◽  
Acoustic Thermometry ◽  
A Value ◽  
New Information ◽  
Thermodynamic Temperatures ◽  
Good Agreement ◽  
Gas Thermometry

Six acoustic isotherms have been plotted in the range 4.2–20 K. When thermodynamic temperatures are calculated from their intercepts on the basis of Batuecas’s value of the gas constant ( R = 8.31441 J mol -1 K -1 ), no significant systematic departure from the results of Berry’s gas thermometry is discernible. If one assumes Berry’s work to be thermodynamically correct and the present work to be thermodynamically linear, a value of the gas constant is implied only (7 ± 27 (lσ)) R / 10 6 higher than that of Batuecas, but 152 R / 10 6 lower than that of Quinn, Colclough & Chandler (Q. C. C.). Such a value is close to that expected from a forthcoming revision of the work of Q. C. C. and is in line with recent criticisms of Rowlinson et al . of their value. If this expectation is borne out gas and acoustic thermometry will be in good agreement in this range. Final results are quoted on the basis of Batuecas’s value of the gas constant and in terms of R to facilitate their recalculation as new information on the value of the gas constant becomes available.

scholarly journals The Active Transport of Oxygen and Carbon Dioxide into the Swim-Bladder of Fish

1966 ◽  
Vol 49 (6) ◽  
pp. 1209-1220 ◽  
Author(s):  
H.J. KUHN ◽  
E. MARTI
Keyword(s):  
Carbon Dioxide ◽  
Lactic Acid ◽  
Active Transport ◽  
Bladder Pressure ◽  
Swim Bladder ◽  
Rete Mirabile ◽  
Partial Pressures ◽  
Gas Gland ◽  
Counter Current ◽  
Good Agreement

The active transport of oxygen and carbon dioxide into the swim-bladder of fish is discussed. The rete mirabile is a capillary network which is involved in the gas secretion into the bladder. The rete is regarded as a counter-current multiplier. Lactic acid which is produced in the gas gland generates in the rete single concentrating effects for oxygen and carbon dioxide; i.e., for equal partial pressures the concentrations of the gases in the afferent rete capillaries are higher than those in the efferent ones. The single concentrating effects were calculated from measurements of sea robin blood (Root, 1931). The multiplication of these effects within the rete for different rete lengths and different transport rates was numerically evaluated. The calculated O2 and CO2 pressures in the bladder are in good agreement with the experimental results of Scholander and van Dam (1953). The descent velocities at equilibrium between bladder pressure and hydrostatic pressure are discussed for fishes with different rete lengths.

Glucose transport in isolated rat adipocytes with measurements of L-arabinose uptake.

1978 ◽  
Vol 234 (2) ◽  
pp. E112 ◽  
Author(s):  
J E Foley ◽  
S W Cushman ◽  
L B Salans
Keyword(s):  
Glucose Transport ◽  
Transport System ◽  
Cytochalasin B ◽  
Competitive Inhibition ◽  
Facilitated Transport ◽  
Time Dependent ◽  
Rat Adipocytes ◽  
A Value ◽  
System Data ◽  
Isolated Rat

Data is presented suggesting that rates of L-arabinose transport, calculated from L-[1-14C]arabinose uptake measurements, can be used as indicators of changes in the rates of glucose transport in isolated rat adipocytes. L-[1-14C]arabinose, at 37 degrees C, was found to be nonmetabolizable and taken up by adipocytes exponentially with time reaching 95% of equilibrium in 30 min. When L-arabinose is corrected for background, the corrected uptake values conform to the time-dependent monoexponential uptake relationshiop predicted for a facilitated transport system and are not significantly different from 0 in the presence of 70 micron cytochalasin B. Transport rates were calculated from corrected uptake values near the half-maximal uptake of L-arabinose and from a value of the total amount of L-arabinose in the cell at equilibrium. Competitive inhibition of L-arabinose transport by glucose and countertransport of L-arabinose in the presence of glucose suggest that L-arabinose and glucose share the same transport system. Data is presented demonstrating the effect of insulin and dexamethasone on the transport system that confirms the conclusions obtained by other investigators using other methods.

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