Sedimentation equilibrium of suspensions of colloidal particles at finite concentrations

1994 ◽  
Vol 272 (12) ◽  
pp. 1582-1589 ◽  
Author(s):  
M. Martin ◽  
M. Hoyos ◽  
D. Lhuillier
Keyword(s):  
Colloidal Particles ◽  
Sedimentation Equilibrium ◽  
Finite Concentrations

scholarly journals Sedimentation of fine colloidal particles adsorbed onto a long polymer chain

1997 ◽  
Vol 75 (9) ◽  
pp. 1248-1255 ◽  
Author(s):  
Waldemar Nowicki ◽  
Grażyna Nowicka
Keyword(s):  
Polymer Chain ◽  
Colloidal Particles ◽  
Polymer Molecule ◽  
Sedimentation Equilibrium ◽  
Brownian Motions ◽  
Stability Model ◽  
High Polymers

A system containing aggregates composed of several fine colloidal particles attached to a single very long polymer molecule is considered. It is shown that the sedimentation equilibrium of the system depends on the extent of restriction over the Brownian motions of particles. On the basis of analysis of sedimentation equilibrium, a simple stability model for such systems is developed. The model elucidates the deterioration of the ability of ultralarge polymers to flocculate fine suspensions. Keywords: high polymers, fine colloidal particles, sedimentation, diffusion, flocculation, stabilization of suspensions.

Polydisperse Colloids Two-Moment Diffusion Model Through Irreversible Thermodynamics Considerations

2020 ◽  
Vol 46 (1) ◽  
pp. 77-90
Author(s):  
Mohamed Bouzghaia ◽  
Ferhat Souidi ◽  
Zakaria Larbi
Keyword(s):  
Statistical Mechanics ◽  
Diffusion Model ◽  
Colloidal Particles ◽  
Numerical Models ◽  
Irreversible Thermodynamics ◽  
Diffusion Problem ◽  
Sedimentation Equilibrium ◽  
Size Spectrum ◽  
Size Segregation ◽  
Classical Size

Abstract This study deals with the problem of diffusion for polydisperse colloids. The resolution of this complex problem usually requires computationally expensive numerical models. By considering the number of colloidal particles and their mass as independent variables, the equations of state for a dilute polydisperse colloid are derived on a statistical mechanics basis. Irreversible thermodynamics is then applied to obtain a simple two-moment diffusion model. The validity of the model is illustrated by comparing its results with those obtained by a classical size spectrum approach, in a sedimentation equilibrium problem and in an unsteady one-dimensional diffusion problem in Stokes–Einstein regime, and under the hypothesis that the size spectrum distribution is stochastic. In the first problem, the two-moment diffusion problem allows to represent rigorously the vertical size segregation induced by gravity, while in the second one, it allows a convenient description of the diffusion of polydisperse colloids by using two coupled diffusion equations, with an accuracy comparable with that of the classical size spectrum approach. The contribution of our work lies primarily in the application of a non-equilibrium thermodynamics methodology to a challenging issue of colloid modeling, namely, polydispersity, by going from statistical mechanics to the derivation of phenomenological coefficients, with the two-moment approach as a guideline.

Ultrastructure of Lymphatic Capillaries in the Transport of Colloidal Particles

1967 ◽  
Vol 25 ◽  
pp. 186-187
Author(s):  
L. V. Leak ◽  
J. F. Burke
Keyword(s):  
Connective Tissue ◽  
Colloidal Particles ◽  
Ultrastructural Level ◽  
Vital Role ◽  
Time Intervals ◽  
Thorium Dioxide ◽  
Lymphatic Capillary ◽  
Tissue Area ◽  
Rapid Removal ◽  
Tissue Fluids

The vital role played by the lymphatic capillaries in the transfer of tissue fluids and particulate materials from the connective tissue area can be demonstrated by the rapid removal of injected vital dyes into the tissue areas. In order to ascertain the mechanisms involved in the transfer of substances from the connective tissue area at the ultrastructural level, we have injected colloidal particles of varying sizes which range from 80 A up to 900-mμ. These colloidal particles (colloidal ferritin 80-100A, thorium dioxide 100-200 A, biological carbon 200-300 and latex spheres 900-mμ) are injected directly into the interstitial spaces of the connective tissue with glass micro-needles mounted in a modified Chambers micromanipulator. The progress of the particles from the interstitial space into the lymphatic capillary lumen is followed by observing tissues from animals (skin of the guinea pig ear) that were injected at various time intervals ranging from 5 minutes up to 6 months.

Deposited emulsion particles in the pores of aluminum oxide film

1978 ◽  
Vol 36 (1) ◽  
pp. 450-451
Author(s):  
Michio Ashida ◽  
Yasukiyo Ueda
Keyword(s):  
Oxide Film ◽  
Acid Solution ◽  
Barrier Layer ◽  
Colloidal Particles ◽  
Oxalic Acid Solution ◽  
Anodic Oxide ◽  
Anodic Oxide Film ◽  
Carbon Replica ◽  
Sectioning Method ◽  
Thin Sectioning

An anodic oxide film is formed on aluminum in an acidic elecrolyte during anodizing. The structure of the oxide film was observed directly by carbon replica method(l) and ultra-thin sectioning method(2). The oxide film consists of barrier layer and porous layer constructed with fine hexagonal cellular structure. The diameter of micro pores and the thickness of barrier layer depend on the applying voltage and electrolyte. Because the dimension of the pore corresponds to that of colloidal particles, many metals deposit in the pores. When the oxide film is treated as anode in emulsion of polyelectrolyte, the emulsion particles migrate onto the film and deposit on it. We investigated the behavior of the emulsion particles during electrodeposition.Aluminum foils (99.3%) were anodized in either 0.25M oxalic acid solution at 30°C or 3M sulfuric acid solution at 20°C. After washing with distilled water, the oxide films used as anode were coated with emulsion particles by applying voltage of 200V and then they were cured at 190°C for 30 minutes.

COUPLING OF COLLOIDAL PARTICLES AND RECOILLESS FRACTION

1976 ◽  
Vol 37 (C6) ◽  
pp. C6-273-C6-276
Author(s):  
H. J. ÜBELHACK ◽  
F. H. WITTMANN
Keyword(s):  
Colloidal Particles ◽  
Recoilless Fraction

Preparation and Properties of Human Prothrombin Complex

1970 ◽  
Vol 24 (03/04) ◽  
pp. 325-333 ◽  
Author(s):  
G. H Tishkoff ◽  
L. C Williams ◽  
D. M Brown
Keyword(s):  
Molecular Weight ◽  
Proteolytic Enzyme ◽  
Enzyme Inhibitor ◽  
Specific Activity ◽  
Crystalline Form ◽  
Sedimentation Equilibrium ◽  
Crystalline Complex ◽  
Interaction Product ◽  
Proteolytic Enzyme Inhibitor ◽  
Purification Scheme

SummaryAs a corollary to our previous studies with bovine prothrombin, we have initiated a study of human prothrombin complex. This product has been isolated in crystalline form as a barium glycoprotein interaction product. Product yields were reduced compared to bovine product due to the increased solubility of the barium glycoprotein interaction product. On occasion the crystalline complex exhibited good yields. The specific activity of the crystalline complex was 1851 Iowa u/mg. Further purification of human prothrombin complex was made by removal of barium and by chromatography on Sephadex G-100 gels. The final product evidenced multiple procoagulant activities (II, VII, IX and X). The monomeric molecular weight determined by sedimentation equilibrium in a solvent of 6 M guanidine-HCl and 0.5% mercaptoethanol was 70,191 ± 3,057 and was homogeneous with respect to molecular weight. This product was characterized in regard to physical constants and chemical composition. In general, the molecular properties of human prothrombin complex are very similar to the comparable bovine product. In some preparations a reversible proteolytic enzyme inhibitor (p-aminophenylarsonic acid) was employed in the ultrafiltration step of the purification scheme to inhibit protein degradation.

How to use alum with cationic dispersed rosin size

TAPPI Journal ◽  
2016 ◽  
Vol 15 (5) ◽  
pp. 331-335 ◽  
Author(s):  
LEBO XU ◽  
JEREMY MYERS ◽  
PETER HART
Keyword(s):  
Zeta Potential ◽  
Colloidal Particles ◽  
Streaming Potential ◽  
Excessive Amount ◽  
Paper Machine ◽  
Optimum Amount ◽  
Potential Measurement ◽  
Streaming Current ◽  
Wide Range ◽  
Laboratory Results

Retention of cationic dispersed rosin size was studied via turbidity measurements on stock filtrate with different alum and dispersed rosin size dosages. Stock charge characteristics were analyzed using both an analysis of charge demand determined via a streaming current detector and an evaluation of zeta potential of the fibers by streaming potential measurement. The results indicated that an optimum amount of alum existed such that good sizing retention was maintained throughout a wide range of dispersed rosin size dosages. However, when an excessive amount of alum was used and fines and colloidal particles were transitioned from anionic to cationic, the cationic size retention was reduced. Laboratory results were confirmed with a paper machine trial. All data suggested that a stock charge study was necessary to identify optimal alum dosage for a cationic dispersed rosin sizing program.

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