scholarly journals Oscillatory Reversible Osmotic Growth of Sessile Saline Droplets on a Floating Polydimethylsiloxane Membrane

Fluids ◽  
2021 ◽  
Vol 6 (7) ◽  
pp. 232
Author(s):  
Pritam Kumar Roy ◽  
Shraga Shoval ◽  
Leonid A. Dombrovsky ◽  
Edward Bormashenko
Keyword(s):  
Mass Transfer ◽  
Mass Transport ◽  
Linear Relationship ◽  
Physical Model ◽  
Water Surface ◽  
Pure Water ◽  
Triple Line ◽  
Pdms Membrane ◽  
Initial Radius ◽  
Evaporation Stage

We report a cyclic growth/retraction phenomena observed for saline droplets placed on a cured poly (dimethylsiloxane) (PDMS) membrane with a thickness of 7.8 ± 0.1 µm floating on a pure water surface. Osmotic mass transport across the micro-scaled floating PDMS membrane provided the growth of the sessile saline droplets followed by evaporation of the droplets. NaCl crystals were observed in the vicinity of the triple line at the evaporation stage. The observed growth/retraction cycle was reversible. A model of the osmotic mass transfer across the cured PDMS membrane is suggested and verified. The first stage of the osmotic growth of saline droplets is well-approximated by the universal linear relationship, whose slope is independent of the initial radius of the droplet. The suggested physical model qualitatively explains the time evolution of the droplet size. The reported process demonstrates a potential for use in industrial desalination.

scholarly journals Oscillatory Reversible Osmotic Growth of Sessile Saline Droplets on the Floating Polydimethylsiloxane Membrane

2021 ◽  
Author(s):  
Pritam Kumar Roy ◽  
Shraga Shoval ◽  
Leonid A. Dombrovsky ◽  
Edward Bormashenko
Keyword(s):  
Mass Transfer ◽  
Mass Transport ◽  
Time Evolution ◽  
Water Surface ◽  
Pure Water ◽  
Pdms Membrane

We report cyclic growth/retraction phenomena observed for saline droplets placed on the cured PDMS membrane with the thickness of 7.8±0.1 µm floating on pure water surface. Osmotic mass transport across the micro-scaled floating PDMS membrane provided the growth of the sessile saline droplets followed by evaporation of the saline droplets. The observed growth/retraction cycle was reversible. The model of the osmotic mass transfer across the cured PDMS membrane is suggested. The model explains semi-quantitatively the time evolution of a droplet.

scholarly journals Aqueous phenol and ethylene glycol solutions in electrohydrodynamic liquid bridging

2011 ◽  
Vol 9 (3) ◽  
pp. 391-403 ◽  
Author(s):  
Mathias Eisenhut ◽  
Xinghua Guo ◽  
Astrid Paulitsch-Fuchs ◽  
Elmar Fuchs
Keyword(s):  
Mass Transport ◽  
Ethylene Glycol ◽  
Bisphenol A ◽  
Anodic Oxidation ◽  
High Voltage ◽  
Electrochemical Behavior ◽  
Pure Water ◽  
Passivation Layer ◽  
Mass Transfers ◽  
Electrophoretic Transport

AbstractThe formation of aqueous bridges containing phenol and ethylene glycol as well as bisphenol-A, hydrochinone and p-cresol under the application of high voltage DC (“liquid bridges”) is reported. Detailed studies were made for phenol and glycol with concentrations from 0.005 to 0.531 mol L−1. Conductivity as well as substance and mass transfers through these aqueous bridges are discussed and compared with pure water bridges. Previously suggested bidirectional mass transport is confirmed for the substances tested. Anodic oxidation happens more efficiently when phenol or glycol are transported from the cathode to the anode since in this case the formation of a passivation layer or electrode poisoning are retarded by the electrohydrodynamic (EHD) flow. The conductivity in the cathode beaker decreases in all experiments due to electrophoretic transport of naturally dissolved carbonate and bicarbonate to the anode. The observed electrochemical behavior is shortly discussed and compared to known mechanisms.

Laboratory Experiments of Mass Transfer in the London Clay

1988 ◽  
Vol 127 ◽  
Author(s):  
P. J. Bourke ◽  
D. Gilling ◽  
N. L. Jefferies ◽  
D. A. Lever ◽  
T. R. Lineham
Keyword(s):  
Mass Transfer ◽  
Porous Media ◽  
Radioactive Waste ◽  
Mass Transport ◽  
Mathematical Models ◽  
Laboratory Experiments ◽  
Naturally Occurring ◽  
Diffusion And Convection ◽  
Waste Repository ◽  
London Clay

ABSTRACTAqueous phase mass transfer through the rocks surrounding a radioactive waste repository will take place by diffusion and convection. This paper presents a comprehensive set of measurements of the mass transfer characteristics for a single, naturally occurring, clay. These data have been compared with the results predicted by mathematical models of mass transport in porous media, in order to build confidence in these models.

The Effect of Shear Flow and Dissolved Gas Diffusion on the Cavitation in a Submerged Journal Bearing

2000 ◽  
Vol 123 (3) ◽  
pp. 494-500 ◽  
Author(s):  
M. Groper ◽  
I. Etsion
Keyword(s):  
Mass Transfer ◽  
Shear Flow ◽  
Mass Transport ◽  
Transport Mechanism ◽  
Journal Bearing ◽  
Gas Diffusion ◽  
Gas Bubble ◽  
Dissolved Gas ◽  
Rotating Shaft ◽  
Mass Transfer Mechanism

Two possible, long standing speculated mechanisms are theoretically investigated in an attempt to understand previous experimental observations of pressure build up in the cavitation zone of a submerged journal bearing. These mechanisms are (1) the shear of the cavity gas bubble by a thin lubricant film dragged through the cavitation zone by the rotating shaft and (2) the mass transfer mechanism which dictates the rate of diffusion of dissolved gas out of and back into the lubricant. A comparison with available experimental results reveals that while the cavitation shape is fairly well predicted by the “shear” mechanism, this mechanism is incapable of generating the level of the experimentally measured pressures, particularly towards the end of the cavitation zone. The “mass transport” mechanism is found inadequate to explain the experimental observations. The effect of this mechanism on the pressure build up in the cavitation zone can be completely ignored.

An engineering model for coupled heat and mass transfer analysis in heated concrete

2002 ◽  
Vol 216 (2) ◽  
pp. 213-222 ◽  
Author(s):  
L y Li ◽  
J A Purkiss ◽  
R T Tenchev
Keyword(s):  
Mass Transfer ◽  
Mass Transport ◽  
Heat And Mass Transfer ◽  
Liquid Water ◽  
Gaseous Mixture ◽  
Sorption Isotherms ◽  
Engineering Model ◽  
Water Saturated ◽  
Mass Transport Equation ◽  
Heated Concrete

In this paper an engineering model for coupled heat and mass transfer in heated concrete is proposed. The model considers the heat transfer and mass transport of liquid water and gaseous mixture. The evaporation of liquid water is assumed to be related to the imbalance pressure between liquid water and water vapour controlled by the ideal gaseous mixture pressure and water saturated pressure. Thus, the content of liquid water is determined directly from its mass transport equation rather than through assumed sorption isotherms as in most existing models. Numerical results for temperature, pore pressure and contents of liquid water and gaseous mixture are presented. Some important features are highlighted through the discussion of results.

Measurement and Modeling of Latent Heat Release During Freezing of Aqueous Solutions in a Small Container

2000 ◽  
Author(s):  
Ramachandra V. Devireddy ◽  
John C. Bischof ◽  
Perry H. Leo ◽  
John S. Lowengrub
Keyword(s):  
Mass Transport ◽  
Heat Release ◽  
Latent Heat ◽  
Pure Water ◽  
Heat Of Fusion ◽  
Freezing Process ◽  
Latent Heat Release ◽  
Aqueous Systems ◽  
Heat And Mass Transport ◽  
Latent Heat Of Fusion

Abstract The latent heat of fusion, ΔHf of a cryobiological medium (a solute laden aqueous solution) is a crucial parameter in the cryopreservation process. The latent heat has often been approximated by that of pure water (∼ 335 mJ/mg). However, recent calorimetric (DSC - Pyris 1) measurements suggest that the actual magnitude of latent heat of fusion during freezing of solute laden aqueous systems is far less. Fourteen different pre-nucleated solute laden aqueous systems (NaCl-H2O, Phosphate Buffered Saline or PBS, serum free RPMI, cell culture medium, glycerol and Anti Freeze Protein solutions) were found to have significantly lower ΔHf than that of pure water (Devireddy and Bischof, 1998). In the present study additional calorimetric experiments are performed at 1, 5 and 20 °C/min in five representative cryobiological media (isotonic or 1× NaCl-H2O, 10× NaCl-H2O, 1× PBS, 5× PBS and 10× PBS) to determine the kinetics of ice crystallization. The temperature (T) and time (t) dependence of the latent heat release is measured. The experimental data shows that at a fixed temperature, the fraction of heat released at higher cooling rates (5 and 20 °C/min) is lower than at 1 °C/min for all the solutions studied. We then sought a simple model that could predict the experimentally measured behavior and examined the full set of heat and mass transport equations during the freezing process in a DSC sample pan. The model neglects the interaction between the growing ice crystals and is most appropriate during the early stages of the freezing process. An examination of the coefficients in the heat and mass transport equations shows that heat transport occurs much more rapidly than solute transport. Hence, the full model reduces to one in which the temperature profile is constant in space while the solute concentration profile obeys the full time and space dependent diffusion equation. The model reveals the important physical parameters controlling the mass transport at the freezing interface and further elucidates the experimental results, i.e. the temperature and time dependence of the latent heat release.

scholarly journals Implementation of Spiegler–Kedem and Steric Hindrance Pore Models for Analyzing Nanofiltration Membrane Performance for Smart Water Production

Membranes ◽  
2018 ◽  
Vol 8 (3) ◽  
pp. 78 ◽  
Author(s):  
Remya Nair ◽  
Evgenia Protasova ◽  
Skule Strand ◽  
Torleiv Bilstad
Keyword(s):  
Mass Transfer ◽  
Reflection Coefficient ◽  
Oil Recovery ◽  
Water Permeability ◽  
Structural Parameters ◽  
Pure Water ◽  
Model Parameters ◽  
Water Production ◽  
Solute Permeability ◽  
Smart Water

A predictive model correlating the parameters in the mass transfer-based model Spiegler–Kedem to the pure water permeability is presented in this research, which helps to select porous polyamide membranes for enhanced oil recovery (EOR) applications. Using the experimentally obtained values of flux and rejection, the reflection coefficient σ and solute permeability Ps have been estimated as the mass transfer-based model parameters for individual ions in seawater. The reflection coefficient and solute permeability determined were correlated with the pure water permeability of a membrane, which is related to the structural parameters of a membrane. The novelty of this research is the development of a model that consolidates the various complex mechanisms in the mass transfer of ions through the membrane to an empirical correlation for a given feed concentration and membrane type. These correlations were later used to predict ion rejections of any polyamide membrane with a known pure water permeability and flux with seawater as a feed that aids in the selection of suitable nanofiltration (NF) for smart water production.

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