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.

scholarly journals Influence of VNIIMK 620 and Itil flax varieties on the rheological properties of wheat dough

2021 ◽  
pp. 33-36
Author(s):  
Tatyana Borisovna Kulevatova ◽  
Lyudmila Nikolaevna Zlobina ◽  
Svetlana Vitalyevna Lyascheva ◽  
Lyubov Vladimirovna Andreeva
Keyword(s):  
Wheat Flour ◽  
Mass Fraction ◽  
Absorption Capacity ◽  
Dispersed Phase ◽  
Rheological Characteristics ◽  
Water Absorption Capacity ◽  
Wheat Dough ◽  
Composite Mixture ◽  
The Stability ◽  
Torque Values

The influence of the mass fraction of flax in the composite mixture on the state of the carbohydrate – amylase complex of the studied system was studied. It was found out that the maximum viscosity of the suspension and the rate of starch gelation in a mixture of wheat flour with whole-ground flax is lower than in the suspension, where the dispersed phase was wheat flour, but higher than that, where the dispersed phase is flax. The influence of flax on the rheological characteristics of wheat dough in the Chopin+ Mixolaba protocol was revealed.  It is found out that with an increase in the mass fraction of flax in the composite mixture from 5 to 20%, the formation time of the test and its water absorption capacity increases, and the stability decreases. When the mass fraction of flax increases, the torque values at the extreme point of the function C2, which characterizes the dilution of the dough, increase; and at the point C5, which characterizes the retrogradation of starch, they decrease.  

Nonlinear Optics of Linear Conjugated Polymers

1992 ◽  
Vol 247 ◽  
Author(s):  
D. Guo ◽  
S. Mazumdar ◽  
G. I. Stegeman ◽  
M. Cha ◽  
D. Neher ◽  
...  
Keyword(s):  
Conjugated Polymers ◽  
Dipole Moments ◽  
Harmonic Signal ◽  
Oscillator Strengths ◽  
Experimental Investigations ◽  
Transition Dipole ◽  
Third Harmonic ◽  
The Third ◽  
Transition Dipole Moments ◽  
Spectral Ranges

The third order nonlinear optical properties of conjugated polymers have been considered promising since the 1970s when Sauteret et al reported large non-resonant values in PTS.[1] Although it is well-understood that the physical origin of the nonlinearities is due to the delocalization of the π-electrons, the details, and how best to calculate them have been the focus of a continuing theoretical dialogue. Until recently, experimental investigations of nonlinearities have been limited to only a few wavelengths. Now third harmonic generation (THG), which accesses only the electronic nonlinearities, can be performed over wide spectral ranges, for example from 500 to 2000 nm. The resulting third harmonic wavelength typically spans the electronic molecular transitions associated with the nonlinearities. By measuring the spectral distribution of both the amplitude and phase of the third harmonic signal, the dominant transitions (between the“essential states”) contributing to the nonlinearity can be identified. Such information is most useful for comparing with theories in which the oscillator strengths (transition dipole moments) for the various molecular transitions are calculated.

Experimental Investigations Concerning Erosive Aggressiveness of Cavitation at Different Test Configurations

Volume 3 ◽  
2004 ◽  
Author(s):  
B. Bachert ◽  
M. Dular ◽  
S. Baumgarten ◽  
G. Ludwig ◽  
B. Stoffel
Keyword(s):  
Mass Loss ◽  
Cavitation Erosion ◽  
Evaluation Method ◽  
Experimental Investigations ◽  
Cavitating Flows ◽  
Test Rig ◽  
The Third ◽  
Long Duration ◽  
Initial Stage ◽  
Test Objects

The experimental results, which will be presented in this paper, demonstrate the significant influence of the flow velocity, respectively the rotational speed, on the erosive aggressiveness of cavitating flows. On two of the three investigated test objects, cavitation erosion can only be observed in the initial stage by the so-called pit-count evaluation method. Developed erosion with mass loss is impossible to measure because of the very long duration until mass loss appears. The third test rig generates a very aggressive type of cavitation, so that mass loss, depending on the tested material, will appear after relatively short durations. In addition, the initial stage of cavitation erosion can be observed. Three different techniques were applied to investigate cavitation erosion in the initial and developed stage. Thereby, the capability of methods to quantify erosive effects in dependence of influencing operating parameters has been proven.

Rheological characteristics of Saudi crude oil emulsions

1991 ◽  
Vol 6 (2) ◽  
pp. 149-160 ◽  
Author(s):  
A.E Omar ◽  
S.M Desouky ◽  
B Karama
Keyword(s):  
Crude Oil ◽  
Rheological Characteristics ◽  
Oil Emulsions

scholarly journals Microwave demulsification of heavy crude oil emulsions: Analysis of acid species recovered in the aqueous phase

Fuel ◽  
2014 ◽  
Vol 128 ◽  
pp. 141-147 ◽  
Author(s):  
Elisângela B. da Silva ◽  
Denisson Santos ◽  
Mayara Paes de Brito ◽  
Regina C.L. Guimarães ◽  
Bianca M.S. Ferreira ◽  
...  
Keyword(s):  
Crude Oil ◽  
Aqueous Phase ◽  
Heavy Crude Oil ◽  
Heavy Crude ◽  
Oil Emulsions

Lode Dependences for Isotropic Pressure-Sensitive Elastoplastic Materials

1990 ◽  
Vol 57 (3) ◽  
pp. 498-506 ◽  
Author(s):  
J. P. Bardet
Keyword(s):  
Experimental Investigations ◽  
Present Communication ◽  
Modified Model ◽  
True Triaxial ◽  
The Third ◽  
Pressure Sensitive ◽  
Isotropic Pressure ◽  
Elastoplastic Materials ◽  
Lode Angle ◽  
Stress Invariant

Experimental investigations indicate that the third stress invariant; Lode angle α affects significantly the behavior of pressure sensitive materials. The present communication presents a formulation to account for α in isotropic pressure-sensitive elastoplastic materials. Seven Lode dependences are reviewed. A new one, referred to as LMN, in proposed to generalize Lade and Duncan, and Matsuoka and Nakai failure surfaces. The formulation is general enough to introduce α into the isotropic elastoplastic modes which are only developed in terms of first and second-stress invariants. As an illustration, several Lode dependences are introduced into Roscoe and Burland model. The performance of the modified model is estimated by comparing experimental and analytical results in the case of true triaxial loadings on normally consolidated clay.

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