Dynamic blocking and dispersions rheology at phase transition

2011 ◽  
Vol 8 (1) ◽  
pp. 77-91
Author(s):  
A.T. Akhmetov ◽  
M.V. Mavletov ◽  
A.A. Valiev
Keyword(s):  
Phase Transition ◽  
Pressure Drop ◽  
Rheological Properties ◽  
Chemical Compounds ◽  
Blocking Effect ◽  
Dispersed Phase ◽  
Simple Chemical ◽  
Dynamic Blocking ◽  
The Difference

In the flow in the microchannel of reverse water hydrocarbon emulsions, it is found the dynamic blocking effect. The essence of the effect is that the flow of the emulsion through the section of the microchannel stops with time, despite the permanent pressure drop. The difference of this work from previous ones is that for the experiments was prepared the emulsion of simple chemical compounds. For visualization of the structure formed in the capillary after blocking, the dispersed phase was introduced fluorescing component. It is studied and compared the rheological properties of the emulsion and formed from it in the phase transition suspension.

Experimental study of hydrodynamic effects in the inverse water hydrocarbon emulsions flow in microchannels

2016 ◽  
Vol 11 (1) ◽  
pp. 30-37 ◽  
Author(s):  
A.A. Rakhimov ◽  
A.T. Akhmetov
Keyword(s):  
High Speed ◽  
Petroleum Industry ◽  
Chemical Compounds ◽  
High Viscosity ◽  
Blocking Effect ◽  
High Speed Photography ◽  
Simple Chemical ◽  
Reported Study ◽  
Dynamic Blocking ◽  
Hydrodynamic Effects

The paper presents results of hydrodynamic and rheological studies of the inverse water hydrocarbon emulsions. The success of the application of invert emulsions in the petroleum industry due, along with the high viscosity of the emulsion, greatly exceeding the viscosity of the carrier phase, the dynamic blocking effect, which consists in the fact that the rate of flow of emulsions in capillary structures and cracks falls with time to 3-4 orders, despite the permanent pressure drop. The reported study shows an increase in viscosity with increasing concentration or dispersion of emulsion. The increase in dispersion of w/o emulsion leads to an acceleration of the onset of dynamic blocking. The use of microfluidic devices, is made by soft photolithography, along with high-speed photography (10,000 frames/s), allowed us to see in the blocking condition the deformation of the microdroplets of water in inverse emulsion prepared from simple chemical compounds.

Steady flow a highly concentrated emulsion in a cylindrical channel with stepped constriction

2016 ◽  
Vol 11 (2) ◽  
pp. 278-283
Author(s):  
N.A. Vorobyev ◽  
A.A. Valiev ◽  
A.T. Akhmetov ◽  
S.F. Urmancheev
Keyword(s):  
Mathematical Model ◽  
Steady Flow ◽  
Cylindrical Channel ◽  
Experimental Studies ◽  
Chemical Compounds ◽  
Dispersed Phase ◽  
Simple Chemical ◽  
Dynamic Blocking ◽  
Concentrated Emulsion

In experimental studies it was found that the effect appear during flow not only in technical emulsions, but also emulsions from simple chemical compounds. It was also suggested that in the region of narrowing of the channel, there is accumulation of particles in the dispersed phase, as a result occurs dynamic blocking. A mathematical model of the flow of a highly concentrated emulsion in a channel with a stepped constriction is constructed.

Features of the flow of dispersions liquid-liquid type through a cylindrical microchannel

2010 ◽  
Vol 7 ◽  
pp. 60-71
Author(s):  
A.T. Akhmetov ◽  
S.P. Sametov
Keyword(s):  
High Pressure ◽  
Pressure Drop ◽  
Physical Mechanism ◽  
Blocking Effect ◽  
Pressure Gradients ◽  
Emulsion Flow ◽  
Flow Through ◽  
Dynamic Blocking ◽  
Liquid Type ◽  
Cylindrical Microchannel

A surprising property of W/O water-hydrocarbon emulsions is revealed which is manifested during flow in microchannels called the phenomenon of dynamic blocking. Effect essence is emulsion flow through the microchannel section ceases with time despite the constantly acting pressure drop. It was experimentally obtained that the phenomenon is observed during the flow of various emulsions of different compositions. It is shown that the phenomenon manifests itself at high pressure gradients although a partial disruption of the dispersions occurs. The paper suggests a physical mechanism for blocking water-hydrocarbon emulsions in microchannels associated with the interaction of nanoscale shells of microdroplets of water.

Dynamic blocking phenomenon of W/O emulsions in section of reservoir

2008 ◽  
Vol 6 ◽  
pp. 19-25
Author(s):  
A.T. Akhmetov ◽  
A.A. Rakhimov ◽  
S.P. Sametov
Keyword(s):  
Mass Transfer ◽  
Pressure Drop ◽  
Constant Pressure ◽  
Blocking Effect ◽  
Fracture Model ◽  
Filtration Flow ◽  
The Core ◽  
Dynamic Blocking ◽  
Different Diameters

On the basis of earlier experiments it is known that the flow of W/O emulsion in the slit-like model and in capillaries of different diameters leads to the fact that the mass transfer of the emulsion ceases with time at with a constant pressure drop. This phenomenon was called as a dynamic blocking effect. In the paper the radial-expanding flow of W/O dispersion in the fracture model and filtration flow in the core were studied at constant pressure drop for the presence of the blocking.

Influence of the aggregate state of the dispersed phase and ultrasonic effect on the flow of emulsions in microchannels

2017 ◽  
Vol 12 (2) ◽  
pp. 187-194
Author(s):  
A.A. Rakhimov ◽  
A.A. Valiev
Keyword(s):  
Carrier Phase ◽  
Oil Industry ◽  
High Viscosity ◽  
Blocking Effect ◽  
Term Effect ◽  
Dispersed Phase ◽  
Short Term ◽  
Aggregate State ◽  
Ultrasonic Effect ◽  
Dynamic Blocking

The paper presents the results of hydrodynamic studies of inverse water hydrocarbon dispersions: emulsions and, prepared from it by freezing the dispersed phase, suspension. In addition to the high viscosity of the emulsion, a much higher viscosity of the carrier phase, the success of the use of invert emulsions in the oil industry is due to the dynamic blocking effect. The effect is that the flow velocity in the capillary structures and cracks decreases by 3-4 orders of magnitude, in spite of the constantly acting pressure drop. The work shows an increase in viscosity with decreasing temperature, while the degree of blocking of the emulsion is higher than that of the suspension prepared from it. The ultrasonic effect makes it possible to control the effect of dynamic blocking. The short-term effect of ultrasound makes it possible to restore the flow, while a longer exposure leads to the fact that blocking occurs even in ultrasound.

Capillary pressure, osmotic pressure and bubble contact areas in foams

Soft Matter ◽  
2021 ◽  
Author(s):  
Reinhard Höhler ◽  
Jordan Seknagi ◽  
Andrew Kraynik
Keyword(s):  
Osmotic Pressure ◽  
Capillary Pressure ◽  
Continuous Phase ◽  
Dispersed Phase ◽  
Average Pressure ◽  
Contact Areas ◽  
The Difference

The capillary pressure of foams and emulsions is the difference between the average pressure in the dispersed phase and the pressure in the continuous phase.

scholarly journals Quality assessment and antioxidant activities of the blossoms of Inula nervosa Wall

2020 ◽  
Author(s):  
Li-xia Hu ◽  
Mei-feng Luo ◽  
Wen-jing Guo ◽  
Xiao He ◽  
Jun Zhou ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Quantitative Data ◽  
Antioxidant Activities ◽  
Quality Criteria ◽  
Chemical Compounds ◽  
Traditional Chinese Medicines ◽  
Chinese Medicines ◽  
Chemical Profiling ◽  
Multiple Origins ◽  
The Difference

Abstract Background Currently, although Inula nervosa Wall is well investigated, little is understood about blossoms of Inula nervosa Wall (BINW). Objective In this work, we systematically investigated the antioxidant activity of the extract from BINW by various standard assays including DPPH free radical ability, ABTS• +, and FRAP. Methods Chemical compounds are tentatively identified through an UHPLC-QTOF-MS system. Furthermore, the contents of nine compounds were detected with UHPLC method coupled with PDA. By carefully analyzing the quantitative data via clusters analysis and PCA. Results 46 compounds are tentatively identified and our results showed that 9 compound samples in 21 batches of BINW collected from different areas could be differentiated and analyzed by a heatmap visualization. In addition, the contents of nine compounds (flavonoids, phenolic acids) exhibited a total of higher amounts and better antioxidant activities from Yunnan than those from other three origins. Conclusions Our study not only developed a powerful platform to explain the difference traditional Chinese medicines (TCMs) species that in closely related through the chemometric and chemical profiling, but also presented a useful method to establish quality criteria of BINW with multiple origins. Highlights To detailly characterize the BINW, we not only performed DPPH, FRAP and ABTS assays to investigate its antioxidant activity, but also established UHPLC-QTOF-MS/MS and UHPLC-PDA based methods to comprehensively identify and qualitatively analyze its components.

Dispersion Flow in Microchannels

2012 ◽  
Author(s):  
Alfir T. Akhmetov ◽  
Marat V. Mavletov ◽  
Sergey P. Sametov ◽  
Artur A. Rakhimov ◽  
Azat A. Valiev ◽  
...  
Keyword(s):  
Aqueous Phase ◽  
Effective Viscosity ◽  
Complex Structure ◽  
Experimental Investigations ◽  
Dispersed Phase ◽  
Rheological Characteristics ◽  
Dense Structure ◽  
The Third ◽  
Dynamic Blocking ◽  
Oil Emulsions

The work is devoted to experimental investigations of the features of flow of dispersions in microchannels. The paper consists of three parts. In the first part the flow of emulsions in smooth contracting cylindrical microchannels is investigated. It is received that a significant role at dynamic blocking of channels is played by the inclusions comparable by size to the diameter of a narrowing. This is in spite of the fact that their influence on the change of a flow rate of emulsion before blocking is insignificant. In the second part the generation of emulsion in a complex structure of microchannels (micromodels) when water is displaced by composition of hydrocarbon with surfactants is investigated. The experimental dependences of the rheological characteristics of emulsions based on the composition of SAS and water at different concentrations of the aqueous phase can explain blocking of a porous structure by generated emulsion. In the third part a comparison of flow of water-in-oil emulsions with the suspension which was obtained by freezing the microdroplets of the aqueous phase of emulsions was studied. It was found that the blocking of suspension is not as complete as in the case of emulsion. It is explained by deformation of the droplets and by formation of a dense structure, as opposed to suspension of beads, through which hydrocarbon phase is filtered. A small increase in effective viscosity due to solidification of freezing droplets of the dispersed phase was found.

Cell-free, protein-synthesizing system of photosynthetic and heterotrophic Rhodospirillum rubrum

1976 ◽  
Vol 22 (2) ◽  
pp. 304-308
Author(s):  
C. T. Chow
Keyword(s):  
Protein Synthesis ◽  
Protease Activity ◽  
Rhodospirillum Rubrum ◽  
Chemical Compounds ◽  
Protein Synthesis Inhibitors ◽  
Free Protein ◽  
Two Systems ◽  
The Difference ◽  
Vitro Protein

An active in vitro protein-synthesizing system has been developed from Rhodospirillum rubrum grown under either photosynthetic or heterotrophic conditions. A protease activity has been found in both of these systems, and this activity can be readily inactivated by treating the cells with KCl and phenylmethyl sulfonylfluoride. The difference in protein-synthesizing activity between the photosynthetic and the heterotrophic systems has been tested in regard to the requirement of various chemicals and the response to protein synthesis inhibitors or various chemical compounds. It has been concluded that only minor differences in protein-synthesizing activity exist between these two systems.

Studies on proper time regularization and the QCD chiral phase transition

2019 ◽  
Vol 34 (01) ◽  
pp. 1950003
Author(s):  
Yu-Qiang Cui ◽  
Zhong-Liang Pan
Keyword(s):  
Phase Transition ◽  
Small Parameter ◽  
Effective Mass ◽  
Finite Temperature ◽  
Chemical Potential ◽  
Proper Time ◽  
Chiral Phase ◽  
Chiral Phase Transition ◽  
Njl Model ◽  
The Difference

We investigate the finite-temperature and zero quark chemical potential QCD chiral phase transition of strongly interacting matter within the two-flavor Nambu–Jona-Lasinio (NJL) model as well as the proper time regularization. We use two different regularization processes, as discussed in Refs. 36 and 37, separately, to discuss how the effective mass M varies with the temperature T. Based on the calculation, we find that the M of both regularization schemes decreases when T increases. However, for three different parameter sets, quite different behaviors will show up. The results obtained by the method in Ref. 36 are very close to each other, but those in Ref. 37 are getting farther and farther from each other. This means that although the method in Ref. 37 seems physically more reasonable, it loses the advantage in Ref. 36 of a small parameter dependence. In addition, we also, find that two regularization schemes provide similar results when T [Formula: see text] 100 MeV, while when T is larger than 100 MeV, the difference becomes obvious: the M calculated by the method in Ref. 36 decreases more rapidly than that in Ref. 37.

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