A Model for Lubrication by Oil-in-Water Emulsions

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
Sy-Wei Lo ◽  
Tzu-Chun Yang ◽  
Yong-An Cian ◽  
Kuo-Cheng Huang
Keyword(s):  
Film Thickness ◽  
Volume Fraction ◽  
Ph Value ◽  
Oil Viscosity ◽  
Water Emulsion ◽  
Oil In Water ◽  
Critical Volume Fraction ◽  
Oil Concentration ◽  
Dynamics Simulations ◽  
Oil In Water Emulsion

A model for oil-in-water emulsion has been developed in this paper. A group of viscosity coefficients transiting smoothly and incessantly from the thick film region to the thin film region is defined. The contributions from disperse and continuous phases to the total lubricant pressure and pressure gradient are functions of the oil concentration and the film thickness. The parameters used in these functions are determined by a series of computational fluid dynamics simulations. The onset of inversion and the viscosity after inversion are also investigated. It is found that the critical volume fraction of oil in the inception of inversion is dependent on the oil viscosity and a factor regarding the combined effects from the emulsifier, pH value, droplet size, and the shear rate. A series of simulations using the proposed model has been carried out and compared with the experimental results, such as the film thickness and the extension of oil pool for various rolling speeds and supply oil concentrations. The numerical outputs are basically in agreement with the experiments.

Preparation of Microcapsules for Self-Healing Polymers

2012 ◽  
Vol 729 ◽  
pp. 205-209
Author(s):  
Anna Czeller ◽  
Tibor Czigány
Keyword(s):  
Optical Microscopy ◽  
Ph Value ◽  
Low Ph ◽  
Wall Material ◽  
Self Healing ◽  
Reaction Conditions ◽  
Water Emulsion ◽  
Oil In Water ◽  
Oil In Water Emulsion ◽  
Polymerization Method

In this paper, melamin-formaldehyde microcapsules filled with pentaerythritol tetrakis (3-mercaptopropionate) (PETMP) or epoxy were prepared via oil-in-water emulsion polymerization method. Two different routes were chosen from literature, and applied with some changes. The effects of modification of reaction conditions on the resulting capsules were studied. It was found that too low pH value in the emulsion causes burst polymerization of the wall material, without microcapsule formation. When pH was set to 4.5 spherical microcapsules were formed. Optical microscopy was used to evaluate the microcapsules.

The Film Formation Mechanism of High Water-Based Emulsions

2010 ◽  
Author(s):  
Jianbin Luo ◽  
Liran Ma
Keyword(s):  
Formation Mechanism ◽  
Film Formation ◽  
High Water ◽  
Metal Working ◽  
Water Emulsion ◽  
Volume Percentage ◽  
Oil In Water ◽  
Oil Concentration ◽  
Oil In Water Emulsion ◽  
Film Formation Mechanism

The oil-in-water emulsion has been widely used as lubricant in metal working such as metal rolling and cutting. The film formation ability of emulsion was considered as an important factor for evaluating the lubricating effectiveness. Although the film formation characteristics have been widely investigated, the mechanism is still not well understood. Furthermore there were seldom results reported on the emulsion with an oil volume percentage less than 1%. The film formation characteristic of emulsions with ultra-low oil concentration (0.005vol%) between a smooth plate and a highly polished steel ball was investigated. The effects of oil concentration and emulsifier concentration were investigated. New viewpoints on the film formation mechanism of emulsion were proposed.

scholarly journals Emulsifying ability of exudate gums obtained from three plant species in Ghana

2020 ◽  
Vol 2 (2) ◽  
pp. 25-31
Author(s):  
John Owusu ◽  
J. H. Oldham ◽  
W. O. Ellis ◽  
G. Owusu-Boateng
Keyword(s):  
Plant Species ◽  
Volume Fraction ◽  
Emulsion Stability ◽  
Continuous Phase ◽  
Water Emulsion ◽  
Food Emulsions ◽  
Acacia Gum ◽  
Oil In Water ◽  
Significant Difference ◽  
Oil In Water Emulsion

Food emulsions are thermodynamically unstable mixtures which can be stabilized with the application of an emulsifier. In Ghana emulsifiers are imported, and this increases the final cost of food emulsions. In this study, gums obtained from three tree plant species in Ghana, i.e. Albizia zygia (Albizia), Khaya senegalensis (Khaya), and Anarcardium occidentale (Cashew), were used to stabilize oil-in-water emulsion, and the stability of the emulsions were measured after centrifugation at 1300 x g for 5 min, and upon pH adjustment (from 2 to 3.5). Quantity of gum (mass), solubility of gum in the continuous phase, viscosity, oil volume fraction, and pH were investigated to determine how they affect emulsion stability.The results indicated with the exception of viscosity, emulsion stability is influenced by all the other factors studied. In addition there was no significant difference (P<0.05) between the emulsion stabilities of food emulsions stabilized by gums of Cashew (0.77-0.86) and Acacia (0.78-0.87). The Pearson’s co-efficient of correlation indicated that the emulsion stability values of the emulsions positively correlated with the solubility of the gums (R2 =0.983 at P<0.05, and0.997 at P<0.01). Although there were no significant differences in the emulsion stability values of emulsions stabilized with Albizia and Khaya gums, both recorded significantly lower (P<0.05) emulsion stability values (0.76-0.85 and 0.75-0.81 respectively) than the Acacia gum (control). The Cashew gum has the potential to be utilized as an emulsifier in the food industry. Keywords: Emulsion, Emulsifier, Acacia gum, Oil-in-water Emulsion, Emulsion stability

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