scholarly journals A mini-module with embedded spacers for high-throughput ultrafiltration

2021 ◽  
Author(s):  
Matthias Wessling
Keyword(s):  
Mass Transport ◽  
Flow Characteristics ◽  
Ultrafiltration Membrane ◽  
Product Line ◽  
Static Mixer ◽  
Hydrodynamic Conditions ◽  
Fluid Interface ◽  
Velocity Imaging ◽  
Flux Increase ◽  
Line P

Ultrafiltration membrane modules suffer from performance losses that arise during filtration from concentration polarization and fouling. Such performance losses are frequently mitigated by controlling the hydrodynamic conditions at the membrane/fluid interface. For instance, the hydrodynamic conditions are manipulated using mesh spacers that act as a static mixer. The design of such spacers is rarely optimized to effectively maintain mass transport through the membrane. Also, the spacer is an additional part added to the feed channel of the membrane module, improving mass transport in general, yet accepting less transport in dead zones.Here, we present a mini module with spacers embedded in the module housing of a flat-sheet ultrafiltration membrane to attain high permeation rates. The performance of two new embedded spacer geometries – staggered herringbone and sinusoidal corrugation – prove experimentally that indeed a CFD-simulated flux increase can be realized during bovine serum albumin (BSA) filtration. The flow characteristics inside the mini module are further investigated using magnetic resonance velocity imaging. The new embedded sinusoidal corrugation spacers outper- form conventional mesh spacer inlays. The fabrication of such module-embedded spacers has been conceptually implemented through an in-silico design and a 3D-printing production process. The latter can be easily realized using injection molding processes, as is now done for the Sartorius ambra(R) crossflow product line.

Mass Transport Modelling in Porous Media Using Delay Differential Equations

2006 ◽  
Vol 258-260 ◽  
pp. 586-591
Author(s):  
António Martins ◽  
Paulo Laranjeira ◽  
Madalena Dias ◽  
José Lopes
Keyword(s):  
Porous Media ◽  
Differential Equations ◽  
Mass Transport ◽  
Delay Differential Equations ◽  
Dispersion Model ◽  
Flow Characteristics ◽  
Convective Transport ◽  
Transport Modelling ◽  
Flow Field Characteristics ◽  
Delay Differential

In this work the application of delay differential equations to the modelling of mass transport in porous media, where the convective transport of mass, is presented and discussed. The differences and advantages when compared with the Dispersion Model are highlighted. Using simplified models of the local structure of a porous media, in particular a network model made up by combining two different types of network elements, channels and chambers, the mass transport under transient conditions is described and related to the local geometrical characteristics. The delay differential equations system that describe the flow, arise from the combination of the mass balance equations for both the network elements, and after taking into account their flow characteristics. The solution is obtained using a time marching method, and the results show that the model is capable of describing the qualitative behaviour observed experimentally, allowing the analysis of the influence of the local geometrical and flow field characteristics on the mass transport.

Experimental study of gas-liquid two-phase bubbly flow characteristics in a static mixer with three twisted leaves

2020 ◽  
Vol 37 (11) ◽  
pp. 1859-1866
Author(s):  
Huibo Meng ◽  
Yuning Hao ◽  
Yanfang Yu ◽  
Zhonggen Li ◽  
Shuning Song ◽  
...  
Keyword(s):  
Experimental Study ◽  
Bubbly Flow ◽  
Flow Characteristics ◽  
Static Mixer ◽  
Two Phase

scholarly journals Comparison of Velocity Profiles for Different Flow Chamber Designs Used in Studies of Microbial Adhesion to Surfaces

2003 ◽  
Vol 69 (10) ◽  
pp. 6280-6287 ◽  
Author(s):  
D. P. Bakker ◽  
A. van der Plaats ◽  
G. J. Verkerke ◽  
H. J. Busscher ◽  
H. C. van der Mei
Keyword(s):  
Velocity Profile ◽  
Mass Transport ◽  
Velocity Profiles ◽  
Flow Chamber ◽  
Channel Length ◽  
Hydrodynamic Conditions ◽  
The Finite Element Method ◽  
Microbial Adhesion ◽  
Shear Rates ◽  
Image Velocimetry

ABSTRACT Flow chambers are commonly used to study microbial adhesion to surfaces under environmentally relevant hydrodynamic conditions. The parallel plate flow chamber (PPFC) is the most common design, and mass transport occurs through slow convective diffusion. In this study, we analyzed four different PPFCs to determine whether the expected hydrodynamic conditions, which control both mass transport and detachment forces, are actually achieved. Furthermore, the different PPFCs were critically evaluated based on the size of the area where the velocity profile was established and constant with a range of flow rates, indicating that valid observations could be made. Velocity profiles in the different chambers were calculated by using a numerical simulation model based on the finite element method and were found to coincide with the profiles measured by particle image velocimetry. Environmentally relevant shear rates between 0 and 10,000 s−1 could be measured over a sizeable proportion of the substratum surface for only two of the four PPFCs. Two models appeared to be flawed in the design of their inlets and outlets and allowed development of a stable velocity profile only for shear rates up to 0.5 and 500 s−1. For these PPFCs the inlet and outlet were curved, and the modeled shear rates deviated from the calculated shear rates by up to 75%. We concluded that PPFCs used for studies of microbial adhesion to surfaces should be designed so that their inlets and outlets are in line with the flow channel. Alternatively, the channel length should be increased to allow a greater length for the establishment of the desired hydrodynamic conditions.

scholarly journals Color and Translucency of Resin-based Composites: Comparison of A-shade Specimens Within Various Product Lines

2018 ◽  
Vol 43 (6) ◽  
pp. 642-655 ◽  
Author(s):  
D Kim ◽  
S-H Park
Keyword(s):  
Blue Light ◽  
Analysis Of Variance ◽  
Product Line ◽  
Product Lines ◽  
B Values ◽  
Light Irradiance ◽  
Wide Range ◽  
Post Hoc ◽  
Line P ◽  
Cielab Color

SUMMARY Objectives: The purpose of this study was to examine and compare the color and translucency of currently available resin-based composites (RBCs) with respect to the shade numbers within each product line. Methods and Materials: Four A-shades (A1, A2, A3, and A3.5) of nine RBC products (Beautifil II, Ceram-X One, Estelite Sigma Quick, Esthet-X HD, Filtek Z250, Filtek Z350 XT, Gradia Direct, Herculite Precis, and Tetric N-Ceram) were investigated. Ten disk-shaped specimens of two different thicknesses (1 and 2 mm) were prepared for each shade of the RBCs. The maximum blue light irradiance (Imax) through the specimen was recorded using a digital optometer. The color measurements were made according to the CIELAB color scale (quantifying L*, a*, and b*) using a colorimeter, and the translucency parameter (TP) was calculated. The L*, a*, b*, TP, and Imax values were compared among the different shades and thicknesses of each product using one-way analysis of variance followed by Tukey's post hoc test. Results: There were significant differences in the color and translucency among the shades and thicknesses within each product line (p<0.001). The L*, Imax, and TP of the 1-mm specimens were higher than those of the 2-mm specimens. The specimens showed equal or lower L* and Imax for higher shade numbers. The a* values differed only slightly among the shades, whereas the b* values were distributed over a relatively wide range. The TP values were independent of the order of shade numbers. Conclusions: Within the limitations of this study, the RBCs became darker and yellowish as the shade number increased. The blue light irradiance decreased in increasing order of the shade numbers. Changes in the translucency demonstrated different trends among the shades, depending on the product line.

Effect of interface shape on advancing and receding fluid-contact angles around spherical particles

Soft Matter ◽  
2015 ◽  
Vol 11 (25) ◽  
pp. 4999-5003 ◽  
Author(s):  
Nesrin Şenbil ◽  
Wei He ◽  
Vincent Démery ◽  
Anthony D. Dinsmore
Keyword(s):  
Contact Line ◽  
Solid Sphere ◽  
Contact Angles ◽  
Spherical Particles ◽  
Interface Shape ◽  
Fluid Interface ◽  
Line P

Experiments show that the angle of contact between a solid sphere and a fluid interface under receding conditions varies with the shape of the fluid interface and of the contact line.

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