Segregation in dissolving binary-component sessile droplets

2016 ◽  
Vol 812 ◽  
pp. 349-369 ◽  
Author(s):  
Erik Dietrich ◽  
Maaike Rump ◽  
Pengyu Lv ◽  
E. Stefan Kooij ◽  
Harold J. W. Zandvliet ◽  
...  
Keyword(s):  
Bulk Water ◽  
The Other ◽  
Polar Component ◽  
Local Concentration ◽  
Polar Components ◽  
Binary Component ◽  
Soluble Component ◽  
Effective Contact ◽  
Soluble Liquid ◽  
Solvatochromic Dye

The dissolution of a single droplet, containing a mixture of oils, in water is experimentally studied. The oils in the droplet varied in terms of their solubility in water and their hydrophobicity. We demonstrate that the polarity of the droplet constituents strongly influences the dissolution dynamics. A binary-component droplet, containing two polar components (one soluble the other insoluble) exhibits a retarded dissolution as compared to a droplet containing only the soluble component. We argue that in this case the mixture in the droplet can be assumed homogeneous, leading to a smaller effective contact area of the soluble liquid in the droplet with the bulk water, and thus delayed dissolution. On the other hand, it is shown that this is not the case when a polar, soluble component is mixed with an insoluble non-polar component, in which case segregation between the different liquids inside the droplet occurs, leading to Marangoni flows and superspreading of the droplet. The segregation is confirmed by volumetric measurements and by the use of a solvatochromic dye in combination with confocal microscopy, which clearly showed that during dissolution local concentration differences inside the droplet developed.

scholarly journals Retention behaviour of acyclic polyfunctional D-arabinose derivatives

2002 ◽  
pp. 35-44 ◽  
Author(s):  
Ljiljana Kolarov ◽  
Eva Loncar ◽  
Radomir Malbasa
Keyword(s):  
Mobile Phase ◽  
Volume Fraction ◽  
Retention Mechanism ◽  
Biologically Active ◽  
Polar Component ◽  
Chiral Molecules ◽  
Retention Behaviour ◽  
Polar Components ◽  
Solute Retention ◽  
Mobile Phases

It is well known that some of biologically active compounds are chiral molecules. Natural monosaccarides are applicable as chiral precursors. D-arabinose is an appropriate chiral precursor in the synthesis of very important biomolecules such as biotin and its analogues and feromon )-exobrevicomin. Acyclic poly functional D- arabinose derivatives are intermediates in the synthesis of the former biomolecules. This paper deals with the retention behaviour and retention mechanism of acyclic poly functional D-arabinose derivatives. The tested compounds have been chromato graphed on silica gel thin layer using binary organic mobile phases with a different polarity. With increasing polarity of the eluent polar components the solute retention is decreasing. The linear relationship is obtained between the values of retention constant, RM' and the logarithm of the mobile phase polar component volume fraction for all solutes tested and eluents used.

Limiting activity coefficients in dilute solutions of nonelectrolytes. II. Determination for polar–nonpolar and polar–polar binary mixtures, and the application of some solubility-parameter treatments

1986 ◽  
Vol 64 (1) ◽  
pp. 198-203 ◽  
Author(s):  
Shapour Afrashtehfar ◽  
Genille C. B. Cave
Keyword(s):  
Binary Mixture ◽  
Activity Coefficients ◽  
Vapor Phase ◽  
Solubility Parameter ◽  
Chromatographic Analysis ◽  
Dipole Interaction ◽  
The Other ◽  
Binary Solutions ◽  
Polar Components ◽  
Induced Dipole

Activity coefficients were determined at 293.15 K for the more dilute component in 24 binary solutions of nonelectrolytes, by gas-chromatographic analysis of the equilibrium vapor phase. One component of the binary mixture was either nitromethane, nitroethane, 1-nitropropane, 2-nitropropane, ethanenitrile, propanenitrile, ethyl ethanoate, or butyl ethanoate; and the other component was either heptane, 1-heptene, or 1,6-heptadiene.From the limiting activity coefficients of these components, some factors that affected their magnitude were identified. The values were also used to test the modifications of Prausnitz, Blanks, and Weimer, of Helpinstill and Van Winkle, and of Keller, Karger, and Snyder to the Scatchard–Hildebrand equation modified to accommodate polar components. In addition, the degree of constancy of the ratio of the dipole – induced dipole interaction parameter for a series of solutes in one solvent to that in another was considered.

A Study of the Removal of Synthetic Sebum from Durable-Press Fabrics, Using a Liquid-Scintillation Technique

1971 ◽  
Vol 41 (8) ◽  
pp. 657-661 ◽  
Author(s):  
Mary Ann Huisman ◽  
Mary Ann Morris
Keyword(s):  
Oleic Acid ◽  
Stearic Acid ◽  
Liquid Scintillation ◽  
Cotton Fabrics ◽  
The Other ◽  
Oily Soil ◽  
Polar Components ◽  
Durable Press ◽  
Untreated Cotton ◽  
Soil Components

A study was made of the retention of a doubly labelled synthetic sebum mixture by durable-press cotton and polyester/cotton fabrics after soiling and laundering. The laundry conditions were ineffective in removing the labelled, oily soil components (tristearin, octadecanol, cholesterol, stearic acid, and oleic acid) from the fabrics. After one soiling and laundering, more tristearin was retained by the fabrics than the other four soil components. The untreated cotton retained significantly less tristearin than DP cotton and the untreated and DP polyester/cotton fabrics. In contrast, after several soilings and launderings, both tristearin and the polar components accumulated on the fabrics and untreated cotton retained significantly more of these components than the other three fabrics.

Structure of Cu Ions in (Cu + Halogen or Chalcogen)-Ion Implanted Silica Glasses

2003 ◽  
Vol 792 ◽  
Author(s):  
Kohei Fukumi ◽  
Akiyoshi Chayahara ◽  
Hiroyuki Kageyama ◽  
Naoyuki Kitamura ◽  
Kohei Kadono ◽  
...  
Keyword(s):  
Silica Glass ◽  
The Other ◽  
Homogeneous Distribution ◽  
Local Concentration ◽  
X Ray ◽  
Silica Glasses ◽  
X Ray Absorption ◽  
Glass Heat ◽  
Cu Ions ◽  
Ion Implanted

ABSTRACTStructure of Cu ions in (Cl+Cu)-, (Br+Cu)-, (I+Cu)-, (S+Cu)- and (Se+Cu)-ion implanted silica glasses has been studied by x-ray absorption and optical absorption spectroscopies. Cu ions formed Cu-O bonds in the as-implanted glasses, due to the homogeneous distribution of Cu ions and the low local concentration of halogen and chalcogen ions in silica glass. Heat treatment at about 600°C caused the formation of bonds between Cu ions and halogen/chalcogen ions without forming Cu halide or chalcogenide crystals. It was deduced that the formation of these bonds was controlled by the diffusion of Cu ions in silica glass. On the other hands, it was inferred that the formation of Cu halide and chalcogenide crystals was controlled not only by the diffusion of halogen/chalcogen ions but also by the diffusion of matrix ions.

scholarly journals Postlockdown Dynamics of COVID-19 in New York, Florida, Arizona, and Wisconsin

2021 ◽  
Author(s):  
Sherry Scott ◽  
Keisha J. Cook ◽  
Kamal Barley
Keyword(s):  
New York ◽  
Herd Immunity ◽  
Mitigation Strategies ◽  
The Other ◽  
Contact Rate ◽  
Testing Rate ◽  
Effective Contact ◽  
The Usa ◽  
The Difference ◽  
Infectious Stage

AbstractThe COVID-19 pandemic is widely studied as it continues to threaten many populations of people especially in the USA, the leading country in terms of both deaths and cases. More and more reports show that the spread of COVID-19 involves infected individuals first passing through a pre-symptomatic infectious stage in addition to the incubation period and that many of the infectious individuals are asymptomatic. In this study, we design and use a mathematical model to primarily address the question of who are the main drivers of COVID-19 - the symptomatic infectious or the presymptomatic and asymptomatic infectious in the states of Florida, Arizona, New York, Wisconsin and the entire United States. We emphasize the benefit of lockdown by showing that for all four states, earlier and later lockdown dates decrease the number of cumulative deaths. This benefit of lockdown is also evidenced by the decrease in the infectious cases for Arizona and the entire US when lockdown is implemented earlier. When comparing the influence of the symptomatic infectious versus the presympomatic/asymptomatic infectious, it is shown that, in general, the larger contribution comes from the latter group. This is seen from several perspectives (1) in terms of daily cases, (2) in terms of daily cases when the influence of one group is targeted over the other by setting the effective contact rate(s) for the non-targeted group to zero, and (3) in terms of cumulative cases and deaths for the US and Arizona when the influence of one group is targeted over the other by setting the effective contact rate(s) for the non-targeted group to zero. The consequences of the difference in the contributions of the two infectious groups is simulated in terms of testing and these simulations show that an increase in testing and isolating for the presymptomatic and asymptomatic infectious group has more impact than an increase in testing for the symptomatic infectious. For example, for the entire US, a 50% increase in testing for the presymptomatic and asymptomatic infectious group results in a 35% decrease in deaths as opposed to a lower 6% decrease in deaths when a 50% increase in testing rate for the symptomatic infectious is implemented. We also see that if the testing for infectious symptomatic is kept at the baseline value and the testing for the presymptomatic and asymptomatic is increased from 0.2 to 0.25, then the control reproduction number falls well below 1. On the other hand, to get even close to such a result when keeping the presymptomatic and asymptomatic at baseline fitted values, the symptomatic infectious testing rate must be increased considerably more - from 0.25 to 1.7. Lastly, we use our model to simulate an implementation of a natural herd immunity strategy for the entire U.S. and for the state of Wisconsin (the most recent epicenter) and we find that such a strategy requires a significant number of deaths and as such is questionable in terms of success. We conclude with a brief summary of our results and some implications regarding COVID-19 control and mitigation strategies.

scholarly journals The Microtubule-severing Proteins Spastin and Katanin Participate Differently in the Formation of Axonal Branches

2008 ◽  
Vol 19 (4) ◽  
pp. 1485-1498 ◽  
Author(s):  
Wenqian Yu ◽  
Liang Qiang ◽  
Joanna M. Solowska ◽  
Arzu Karabay ◽  
Sirin Korulu ◽  
...  
Keyword(s):  
The Other ◽  
Cultured Neurons ◽  
Local Concentration ◽  
Microtubule Severing ◽  
Large Numbers ◽  
Branch Formation

Neurons express two different microtubule-severing proteins, namely P60-katanin and spastin. Here, we performed studies on cultured neurons to ascertain whether these two proteins participate differently in axonal branch formation. P60-katanin is more highly expressed in the neuron, but spastin is more concentrated at sites of branch formation. Overexpression of spastin dramatically enhances the formation of branches, whereas overexpression of P60-katanin does not. The excess spastin results in large numbers of short microtubules, whereas the excess P60-katanin results in short microtubules intermingled with longer microtubules. We hypothesized that these different microtubule-severing patterns may be due to the presence of molecules such as tau on the microtubules that more strongly shield them from being severed by P60-katanin than by spastin. Consistent with this hypothesis, we found that axons depleted of tau show a greater propensity to branch, and that this is true whether or not the axons are also depleted of spastin. We propose that there are two modes by which microtubule severing is orchestrated during axonal branch formation, one based on the local concentration of spastin at branch sites and the other based on local detachment from microtubules of molecules such as tau that regulate the severing properties of P60-katanin.

Scanning-DLTS and TEM-investigations in Lec-GaAs: New arguments on the EL2-generation mechanism

1990 ◽  
Vol 48 (4) ◽  
pp. 616-617
Author(s):  
O. Breitenstein ◽  
R. Fornari ◽  
C. Frigeri ◽  
R. Gleichmann ◽  
J. Heydenreich
Keyword(s):  
Electron Beam ◽  
Detection Limit ◽  
Space Charge ◽  
Spatial Resolution ◽  
Deep Level ◽  
Schottky Diodes ◽  
The Other ◽  
Local Concentration ◽  
Lec Gaas ◽  
Dependent Parameter

Scanning-DLTS (SDLTS) uses the focused electron beam of a SEM to locally excite deep levels in semiconductor space charge structures (Schottky-diodes or pn-junctions). This results in rf-capacitance changes of the sample, which are detected as a function of temperature by a specialized high-sensitive DLTS-spectrometer leading to a measure of the local concentration of energetically well-defined deep level defects. The detection limit of this technique, hitherto being around 1013cm-3 for a spatial resolution of a few microns, exceeds that of most of the other microanalytical tools by several orders of magnitude.LEC-GaAs crystals have been grown from melts with a Ga/As-fTaction from varying e.g. from 1.05 at the top to 1.35 at the bottom of the crystals. Thus, the decisive position-dependent parameter of the material was the melt-stoichiometry. TEM-investigations revealed the grown-in dislocations and of perfect (interstitial-type) discolation loops, both being decorated with As-rich precipitates(Fig. 1).

Characterization of Tubercles in Cast Iron Water Distribution Pipes Using Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS)

1997 ◽  
Vol 3 (S2) ◽  
pp. 787-788
Author(s):  
P. Sarin ◽  
W.M. Kriven ◽  
V.L. Snoeyink
Keyword(s):  
Electron Microscopy ◽  
Cast Iron ◽  
Water Distribution ◽  
Potable Water ◽  
Bulk Water ◽  
The Other ◽  
Chemical Structures ◽  
Inner Surface ◽  
Scanning Electron

Corrosion of cast iron (C.I.) pipe often results in the formation of “tubercles” on the inner surface of the pipe. Tubercles are layered deposits formed by the stacking of several layers of corrosion products one on top of the other (Fig.l). Tubercles not only increase the amount of energy required for transport of water but are also considered the main source of turbidity in potable water. Their chemical and physical characteristics are important factors which affect the release of iron into the bulk water.Tubercles are extremely complex systems. They may be highly crystalline in nature, with iron occurring in chemical structures, such as siderite (FeCO3), goethite (α-FeOOH), magnetite (Fe3O4) and lepidocrocite (γ-FeOOH) or they may be highly amorphous. Tubercles vary in height from a few millimeters to a few centimeters. They exhibit distinct layers which are formed over varying periods of time ranging from a few months to a century.

Biodegradation of Paraffin Crude Oil by an Isolated Pseudomonas aeruginosa N2 for Enhanced Oil Recovery

2012 ◽  
Vol 616-618 ◽  
pp. 924-930 ◽  
Author(s):  
Xiao Meng ◽  
Zhong Zhi Zhang ◽  
Shan Wang ◽  
Afang Shen
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Crude Oil ◽  
Enhanced Oil Recovery ◽  
Relative Abundance ◽  
Oil Recovery ◽  
Polar Component ◽  
Oil Viscosity ◽  
Interface Tension ◽  
Polar Components ◽  
Ft Icr Ms

In this study, Pseudomonas aeruginosa N2 was used to investigate the effects of biodegradation on paraffin crude oil for microbial enhanced oil recovery. Hydrocarbon degradation and the polar component production were illustrated by different analysis methods, respectively. Strain N2 had a high emulsion capability to enhance the dissolution of crude oil, which improved the utilization of crude oil. GC-MS results showed that the relative abundance of heavy hydrocarbon was decreased after biodegradation with the increase of hydrocarbon fractions of C19, C20and C25. ESI FT ICR-MS was used to study the changes of the polar components. Analysis revealed that the relative abundance of N1and O1species was decreased, corresponding to the increase of the relative abundance of N1O1, N1O2, N1O3and O2species. These polar components have the effort to reduce the interface tension and oil viscosity, thereby promoting anti-coalescence and reducing plugging to enhanced oil recovery.

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