The Increase of Ablation Effectiveness by Surface-Active Compounds

1965 ◽  
Vol 16 (3) ◽  
pp. 289-301
Author(s):  
B. Steverding
Keyword(s):  
Steady State ◽  
Stagnation Point ◽  
Liquid Layer ◽  
Active Compounds ◽  
Surface Active Agents ◽  
Blunt Bodies ◽  
Glassy Materials ◽  
Surface Active ◽  
Surface Active Compounds ◽  
Coefficient Of Diffusion

SummaryThe heat of ablation of glassy materials can be improved by surface-active agents. The degree of improvement is more pronounced at high flight velocities and depends strongly on the coefficient of diffusion in the liquid layer. The analysis is carried out near the stagnation point of blunt bodies for steady state ablation.

scholarly journals Interactions of Ionic Liquids and Spirocyclic Compounds with Liposome Model Membranes. A Steady-State Fluorescence Anisotropy Study

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Antti H. Rantamäki ◽  
Wen Chen ◽  
Paulus Hyväri ◽  
Jussi Helminen ◽  
Gabriel Partl ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Steady State ◽  
Fluorescence Anisotropy ◽  
Active Compounds ◽  
Steady State Fluorescence ◽  
Structure Relation ◽  
Surface Active ◽  
Spirocyclic Compounds ◽  
Surface Active Compounds

AbstractUnderstanding the toxicity of ionic liquids (ILs) is crucial in the search of greener chemicals. By comparing in vivo toxicity and in vitro interactions determined between compounds and biomimetic lipid membranes, more detailed toxicity vs. structure relation can be obtained. However, determining the interactions between non-surface-active compounds and liposomes has been a challenging task. Organisational changes induced by ILs and IL-like spirocyclic compounds within 1,6-diphenyl-1,3,5-hexatriene-doped biomimetic liposomes was studied by steady-state fluorescence anisotropy technique. The extent of organisational changes detected within the liposome bilayers were compared to the toxicity of the compounds determined using Vibrio Fischeri bacteria. Four liposome compositions made of pure 1-palmitoyl-2-oleyl-sn-glycero-3-phosphocoline (POPC) and mixtures of POPC, 1-palmitoyl-2-oleyl-sn-glycero-3-phosphoserine (POPS), and cholesterol (Chol) were tested as biomimetic models. Changes observed within the POPC/POPS/Chol 55:20:25 bilayers correlated the best with the toxicity results: ten out of twelve compounds followed the trend of increasing bilayer disorder – increasing toxicity. The study suggests that the toxicity of non-surface-active compounds is dependent on their ability to diffuse into the bilayers. The extent of bilayer’s organisational changes correlates rather well with the toxicity of the compounds. Highly sensitive technique, such as fluorescence anisotropy measurements, is needed for detecting subtle changes within the bilayer structures.

The Isolation and Prospect of Biosurfactants

2012 ◽  
Vol 550-553 ◽  
pp. 1124-1127
Author(s):  
Yun Yun Xu ◽  
Tao Zhang ◽  
Xin Nian Li ◽  
Lei Chen ◽  
Hao Wang
Keyword(s):  
Environmental Remediation ◽  
Oil Production ◽  
Active Compounds ◽  
Strong Interest ◽  
Biological Technology ◽  
Natural Surface ◽  
Potential Applications ◽  
Surface Active ◽  
Surface Active Compounds

Biosurfactants are natural surface-active compounds mainly synthesized by microorganisms, which have distinct advantages like no secondly pollution and friendly to environment compared with chemical surfactants. With the development of modern biological technology, biosurfactants have been shown a variety of potential applications, including medicine, agriculture, oil production and environmental remediation, so it has already caused many researchers a strong interest in the production of biosurfactants making use of biological technology. A review is made from the isolation of biosurfactants. In addition, on the foundation of the analysis,several suggestions about the development of biosurfactants are proposed.

scholarly journals Aerosol hygroscopicity at high (99 to 100%) relative humidities

2009 ◽  
Vol 9 (4) ◽  
pp. 15595-15640 ◽  
Author(s):  
C. R. Ruehl ◽  
P. Y. Chuang ◽  
A. Nenes
Keyword(s):  
Surface Tension ◽  
Inorganic Compounds ◽  
Droplet Diameter ◽  
Pure Water ◽  
Sodium Dodecyl ◽  
Bulk Solution ◽  
Active Compounds ◽  
Surface Active ◽  
Surface Active Compounds ◽  
Aerosol Hygroscopicity

Abstract. The hygroscopicity of an aerosol largely determines its influence on climate and, for smaller particles, atmospheric lifetime. While much aerosol hygroscopicity data is available at lower relative humidities (RH) and under cloud formation conditions (RH>100%), relatively little data is available at high RH (99.2 to 99.9%). We measured the size of droplets at high RH that had formed on particles composed of one of seven compounds with dry diameters between 0.1 and 0.5 μm, and calculated the hygroscopicity of these compounds. We use a parameterization of the Kelvin term, in addition to a standard parameterization (κ) of the Raoult term, to express the hygroscopicity of surface-active compounds. For inorganic compounds, hygroscopicity could reliably be predicted using water activity data and assuming a surface tension of pure water. In contrast, most organics exhibited a slight to mild increase in hygroscopicity with droplet diameter. This trend was strongest for sodium dodecyl sulfate (SDS), the most surface-active compound studied. The results suggest that partitioning of surface-active compounds away from the bulk solution, which reduces hygroscopicity, dominates any increases in hygroscopicity due to reduced surface tension. This is opposite to what is typically assumed for soluble surfactants. Furthermore, we saw no evidence that micellization limits SDS activity in micron-sized solution droplets, as observed in macroscopic solutions. These results suggest that while the high-RH hygroscopicity of inorganic compounds can be reliably predicted using readily available data, surface-activity parameters obtained from macroscopic solutions with organic solutes may be inappropriate for calculations of the hygroscopicity of micron-sized droplets.

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