Interbubble gas transfer in persistent foams resulting from surfactant mixtures

2007 ◽  
pp. 143-147 ◽  
Author(s):  
G. Marion ◽  
K. Benabdeljalil ◽  
J. Lachaise
Keyword(s):  
Gas Transfer ◽  
Surfactant Mixtures

Phase behavior of cationic and anionic surfactants at low concentrations

1992 ◽  
Vol 50 (1) ◽  
pp. 694-695
Author(s):  
E. Naranjo
Keyword(s):  
Phase Behavior ◽  
Structural Characterization ◽  
Dynamic Systems ◽  
Anionic Surfactants ◽  
Intermolecular Forces ◽  
Stable Form ◽  
Surfactant Mixtures ◽  
Low Concentrations ◽  
Cationic And Anionic Surfactants ◽  
General Method

Equilibrium vesicles, those which are the stable form of aggregation and form spontaneously on mixing surfactant with water, have never been demonstrated in single component bilayers and only rarely in lipid or surfactant mixtures. Designing a simple and general method for producing spontaneous and stable vesicles depends on a better understanding of the thermodynamics of aggregation, the interplay of intermolecular forces in surfactants, and an efficient way of doing structural characterization in dynamic systems.

Eurasian Economic union: Prospects and challenges for Development

2015 ◽  
pp. 87-108 ◽  
Author(s):  
A. Knobel
Keyword(s):  
Oil And Gas ◽  
Economic Effects ◽  
Necessary Condition ◽  
Gas Transfer ◽  
Eurasian Economic Union ◽  
Economic Union ◽  
Food Imports ◽  
Cis Countries ◽  
Integration Problems ◽  
Integration Challenge

The paper is devoted to the analysis of development prospects and problems of Eurasian Economic Union (EAEU) of Russia, Kazakhstan, Belarus and Armenia. It considers integration problems inside EAEU, interactions of EAEU with other CIS countries and with countries from the rest of the world. The paper shows that the major integration challenge inside EAEU is the domination of the redistributive motive over the creative one. It estimates the value of the oil and gas transfer from Russia to other EAEU members and the influence of the Russian tax maneuver on this transfer. The paper shows the need in redistribution mechanism inside EAEU as a necessary condition for getting the potential positive economic effects of free trade with other countries. It also assesses the risks for EAEU due to Russian embargo for food imports from countries of the sanctions list and possible application of tariff in the trade with Ukraine.

Solubilization of Itraconazole by Surfactants and Phospholipid-Surfactant Mixtures: Interplay of Amphiphile Structure, pH and Electrostatic Interactions

2020 ◽  
Author(s):  
Zahari Vinarov ◽  
Gabriela Gancheva ◽  
Nikola Burdzhiev ◽  
Slavka S. Tcholakova
Keyword(s):  
Nmr Spectroscopy ◽  
Electrostatic Interactions ◽  
Triazole Ring ◽  
Water Soluble ◽  
Single Chain ◽  
Surfactant Mixtures ◽  
Solubilization Capacity ◽  
Water Soluble Drugs ◽  
Hydrophobic Chain ◽  
Brick Dust

Although surfactants are frequently used in enabling formulations of poorly water-soluble drugs, the link between their structure and drug solubilization capacity is still unclear. We studied the solubilization of the “brick-dust” molecule itraconazole by 16 surfactants and 3 phospholipid:surfactant mixtures. NMR spectroscopy was used to study in more details the drug-surfactant interactions. Very high solubility of itraconazole (up to 3.6 g/L) was measured in anionic surfactant micelles at pH = 3, due to electrostatic attraction between the oppositely charged (at this pH) drug and surfactant molecules. <sup>1</sup>H NMR spectroscopy showed that itraconazole is ionized at two sites (2+ charge) at these conditions: in the phenoxy-linked piperazine nitrogen and in the dioxolane-linked triazole ring. The increase of amphiphile hydrophobic chain length had a markedly different effect, depending on the amphiphile type: the solubilization capacity of single-chain surfactants increased, whereas a decrease was observed for double-chained surfactants (phosphatidylglycerols). The excellent correlation between the chain melting temperatures of phosphatidylglycerols and itraconazole solubilization illustrated the importance of hydrophobic chain mobility. This study provides rules for selection of itraconazole solubilizers among classical single-chain surfactants and phospholipids. The basic physics underpinning the described effects suggests that these rules should be transferrable to other “brick-dust” molecules.

Air-Water Gas Transfer in Coastal Waters

1999 ◽  
Author(s):  
Bernd Jaehne ◽  
Jochen Klinke
Keyword(s):  
Coastal Waters ◽  
Gas Transfer ◽  
Water Gas

Variations in gas transfer from dispersed bubbles

1967 ◽  
Vol 2 (1) ◽  
pp. 73-94
Author(s):  
K. L. Murphy ◽  
A. W. Wilson
Keyword(s):  
Gas Transfer

Mass Transfer Limited Wet Oxidation in Trickle-Bed Reactor

1998 ◽  
Vol 63 (11) ◽  
pp. 1938-1944 ◽  
Author(s):  
Vratislav Tukač ◽  
Jiří Vokál ◽  
Jiří Hanika
Keyword(s):  
Supported Catalyst ◽  
Reaction Rates ◽  
Gas Transfer ◽  
Wet Oxidation ◽  
Reactor Performance ◽  
Catalytic Wet Oxidation ◽  
Environmental Application ◽  
Trickle Bed Reactor ◽  
Fine Glass ◽  
Trickle Bed

Catalytic activity of CuO-supported catalyst in phenol oxidation, and the influence of reaction conditions, viz. temperature (125-170 °C), oxygen partial pressure (1-7 MPa) and liquid feed (30-760 ml h-1), in the continuous operation using 17.9 mm i.d. trickle-bed reactor is presented. The hydrodynamic impact on the three-phase trickle-bed reactor performance in an environmental application of catalytic wet oxidation was also investigated. The results of trickle-bed operation were strongly influenced by wetting efficiency. An insufficient catalyst wetting can be to compensated by filling the catalyst bed voids by fine glass spheres. In the case of the gas transfer limited reaction, a better wetting of the catalyst can lead to worse reactor performance due to lower reaction rates.

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