An Exploration of the Effects of Dissolved Ionic Solids on Bubble Merging in Water and Its Impact on the Leidenfrost Transition

2010 ◽  
Author(s):  
Yu Gan ◽  
Van P. Carey
Keyword(s):  
Liquid Film ◽  
Theoretical Models ◽  
Md Simulations ◽  
Cast Aluminum ◽  
Film Stability ◽  
Instability Theory ◽  
Ionic Solids ◽  
Free Liquid Film ◽  
The Stability ◽  
Dissolved Salts

Theoretical models and MD simulation studies suggest that dissolved salts tend to alter the surface tension at liquid vapor interfaces and affect the stability of the free liquid film between adjacent bubbles. Recent modeling of the Leidenfrost phenomenon also indicates that bubble merging is a key mechanism affecting the Leidenfrost transition conditions. This investigation summarizes the results of an investigation of the effects of dissolved salts on liquid film stability and bubble merging in the aqueous solution. The interaction of pairs of bubbles injected into solution with different dissolved salt concentrations was studied experimentally to determine the probability of merging from statistics for ensembles of bubble pairs. The results of these experiments indicate that very low dissolved salt concentrations can strongly reduce the tendency of adjacent bubbles to merge, implying that the presence of the dissolved salt in such cases strongly enhances the stability of the free liquid film between adjacent bubbles. The trends are compared to predictions of free liquid film stability by wave instability theory and MD simulations. These trends are also compared to experimental data indicating the effects of dissolved salt on the Leidenfrost transition. These comparisons indicate that the suppression of merging due to the effects of some dissolved salts can significantly alter the Leidenfrost transition conditions. The implications of this in quenching of cast aluminum or steel parts using water of variable hardness are also discussed.

Stability and collapse of holes in liquid layers

2018 ◽  
Vol 855 ◽  
pp. 1130-1155 ◽  
Author(s):  
Cunjing Lv ◽  
Michael Eigenbrod ◽  
Steffen Hardt
Keyword(s):  
Liquid Film ◽  
Power Laws ◽  
Theoretical Models ◽  
Liquid Volume ◽  
Capillary Length ◽  
Minimum Thickness ◽  
The Stability ◽  
Film Profile ◽  
Hole Closure ◽  
Good Agreement

We investigate experimentally and theoretically the stability and collapse of holes in liquid layers on bounded substrates with various wettabilities. It is shown that for a liquid layer with a thickness of the order of the capillary length, a stable hole exists when the hole diameter is bigger than a critical value $d_{c}$. Consequently, a further increase of the liquid volume causes the hole to collapse. It is found that$d_{c}$increases with the size of the container, but its dependence on the contact angle is very weak. The experimental results are compared with theory, and good agreement is obtained. Moreover, we present investigations of the dynamics of the hole and the evolution of the liquid film profile after the collapse. The diameter of the hole during collapse and the minimum thickness of the liquid film shortly after the collapse obey different power laws with time. Simple theoretical models are developed which indicate that the collapse of the hole is triggered by surface tension and the subsequent closure process results from inertia, whereas the growth of the liquid column after hole closure results from the balance between the capillary force and inertia. Corresponding scaling coefficients are determined.

Stability of Thin Free Liquid Films and the Onset Conditions for Film Rupture: A MD Simulation Study

2007 ◽  
Author(s):  
Yu Gan ◽  
Van P. Carey
Keyword(s):  
Liquid Film ◽  
Density Fluctuation ◽  
Md Simulation ◽  
Md Simulations ◽  
Nucleate Boiling ◽  
Liquid Films ◽  
Wave Perturbation ◽  
Film Rupture ◽  
Free Film ◽  
The Stability

Free liquid films bounded on two sides by vapor are of particular interest in nucleate boiling process because the merging of bubbles is ultimately associated with the rupture of a liquid film separating the vapor inside the bubbles. The stability and conditions for the free film rupture are therefore of central importance to the merging process because they dictate whether coalescence is likely to occur. Most previous studies of free film stability have focused on a continuum model of wave phenomena at the interfaces of the film. In the investigation summarized here, molecular dynamics (MD) simulation was used to explore the stability of free films of liquid argon surrounded by saturated argon vapor. The MD simulations predict that the wave perturbation or density fluctuation induced by the thermodynamic intrinsic instability can lead to rupture of the liquid film, as its thickness decreases below a critical value. It further predicts that the critical film thickness derived from density fluctuation increases with system temperature. These predictions were also compared with those of conventional interface wave perturbation analysis. The result of this investigation suggests that during bubble merging, thermodynamic instability of the liquid phase may play a role in the onset of film rupture as the liquid film separating the bubbles gets progressively thinner.

The Stability of Evaporating Thin Liquid Film Containing Insoluble Surfactant on Heated Substrate

2012 ◽  
Vol 614-615 ◽  
pp. 191-194
Author(s):  
Chun Xi Li ◽  
Bing Lu ◽  
Xue Min Ye
Keyword(s):  
Liquid Film ◽  
Evolution Equations ◽  
Thin Liquid Film ◽  
Nonlinear Evolution Equations ◽  
Linear Stability Theory ◽  
Film Stability ◽  
Heated Substrate ◽  
Insoluble Surfactant ◽  
The Stability ◽  
Evaporation Number

Flow of evaporating thin liquid film containing insoluble surfactant on a uniformally heated substrate is considered in this paper. Coupled nonlinear evolution equations for the film thickness and surfactant concentration are derived on the base of lubrication theory and reasonable boundary conditions. The flow stability of the thin liquid film has been studied using normal mode method according to the linear stability theory. The results show that the film stability is promoted by increasing the Capillary number and the surfactant Peclet number, while increasing the Marangoni number, the interface resistance number, the vapor recoil number and the evaporation number can reduce the stability of the system.

Polysaccharide Structures in the Outer Mucilage of Arabidopsis Seeds Visualized by AFM

2020 ◽  
Author(s):  
MAK Williams ◽  
V Cornuault ◽  
AH Irani ◽  
VV Symonds ◽  
J Malmström ◽  
...  
Keyword(s):  
Average Length ◽  
American Chemical Society ◽  
Md Simulations ◽  
Chemical Society ◽  
Side Chains ◽  
Rhamnogalacturonan I ◽  
Afm Imaging ◽  
Minor Population ◽  
The Stability ◽  
A Minor

© 2020 American Chemical Society. Evidence is presented that the polysaccharide rhamnogalacturonan I (RGI) can be biosynthesized in remarkably organized branched configurations and surprisingly long versions and can self-assemble into a plethora of structures. AFM imaging has been applied to study the outer mucilage obtained from wild-type (WT) and mutant (bxl1-3 and cesa5-1) Arabidopsis thaliana seeds. For WT mucilage, ordered, multichain structures of the polysaccharide RGI were observed, with a helical twist visible in favorable circumstances. Molecular dynamics (MD) simulations demonstrated the stability of several possible multichain complexes and the possibility of twisted fibril formation. For bxl1-3 seeds, the imaged polymers clearly showed the presence of side chains. These were surprisingly regular and well organized with an average length of ∼100 nm and a spacing of ∼50 nm. The heights of the side chains imaged were suggestive of single polysaccharide chains, while the backbone was on average 4 times this height and showed regular height variations along its length consistent with models of multichain fibrils examined in MD. Finally, in mucilage extracts from cesa5-1 seeds, a minor population of chains in excess of 30 μm long was observed.

In Silico and in Vitro Evaluation of Deamidation Effects on the Stability of the Fusion Toxin DAB389IL-2

2019 ◽  
Vol 16 (4) ◽  
pp. 307-313 ◽  
Author(s):  
Nasrin Zarkar ◽  
Mohammad Ali Nasiri Khalili ◽  
Fathollah Ahmadpour ◽  
Sirus Khodadadi ◽  
Mehdi Zeinoddini
Keyword(s):  
In Silico ◽  
Catalytic Domain ◽  
Md Simulations ◽  
Special Importance ◽  
Native Form ◽  
Vitro Experiment ◽  
In Vitro Experiment ◽  
Pharmaceutical Protein ◽  
The Stability

Background: DAB389IL-2 (Denileukin diftitox) as an immunotoxin is a targeted pharmaceutical protein and is the first immunotoxin approved by FDA. It is used for the treatment of various kinds of cancer such as CTCL lymphoma, melanoma, and Leukemia but among all of these, treatment of CTCL has special importance. DAB389IL-2 consists of two distinct parts; the catalytic domain of Diphtheria Toxin (DT) that genetically fused to the whole IL-2. Deamidation is the most important reaction for chemical instability of proteins occurs during manufacture and storage. Deamidation of asparagine residues occurs at a higher rate than glutamine residues. The structure of proteins, temperature and pH are the most important factors that influence the rate of deamidation. Methods: Since there is not any information about deamidation of DAB389IL-2, we studied in silico deamidation by Molecular Dynamic (MD) simulations using GROMACS software. The 3D model of fusion protein DAB389IL-2 was used as a template for deamidation. Then, the stability of deamidated and native form of the drug was calculated. Results: The results of MD simulations were showed that the deamidated form of DAB389IL-2 is more unstable than the normal form. Also, deamidation was carried by incubating DAB389IL-2, 0.3 mg/ml in ammonium hydrogen carbonate for 24 h at 37o C in order to in vitro experiment. Conclusion: The results of in vitro experiment were confirmed outcomes of in silico study. In silico and in vitro experiments were demonstrated that DAB389IL-2 is unstable in deamidated form.

scholarly journals Thermally Stimulated Desorption Optical Fiber-Based Interrogation System: An Analysis of Graphene Oxide Layers’ Stability

Photonics ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 70
Author(s):  
Maria Raposo ◽  
Carlota Xavier ◽  
Catarina Monteiro ◽  
Susana Silva ◽  
Orlando Frazão ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Optical Fiber ◽  
Optical Fiber Sensor ◽  
Layer By Layer ◽  
Film Stability ◽  
A Value ◽  
Device Reliability ◽  
Sensor Devices ◽  
Lbl Films ◽  
The Stability

Thin graphene oxide (GO) film layers are being widely used as sensing layers in different types of electrical and optical sensor devices. GO layers are particularly popular because of their tuned interface reflectivity. The stability of GO layers is fundamental for sensor device reliability, particularly in complex aqueous environments such as wastewater. In this work, the stability of GO layers in layer-by-layer (LbL) films of polyethyleneimine (PEI) and GO was investigated. The results led to the following conclusions: PEI/GO films grow linearly with the number of bilayers as long as the adsorption time is kept constant; the adsorption kinetics of a GO layer follow the behavior of the adsorption of polyelectrolytes; and the interaction associated with the growth of these films is of the ionic type since the desorption activation energy has a value of 119 ± 17 kJ/mol. Therefore, it is possible to conclude that PEI/GO films are suitable for application in optical fiber sensor devices; most importantly, an optical fiber-based interrogation setup can easily be adapted to investigate in situ desorption via a thermally stimulated process. In addition, it is possible to draw inferences about film stability in solution in a fast, reliable way when compared with the traditional ones.

THE STABILITY ANALYSIS OF HEAT TRANSFER IN SATURATED LIQUID FILM OF THE SPECIAL MATERIALS

2005 ◽  
Vol 19 (28n29) ◽  
pp. 1547-1550
Author(s):  
YOULIANG CHENG ◽  
XIN LI ◽  
ZHONGYAO FAN ◽  
BOFEN YING
Keyword(s):  
Heat Transfer ◽  
Differential Equation ◽  
Surface Tension ◽  
Stability Analysis ◽  
Liquid Film ◽  
Nonlinear Relationship ◽  
Saturated Liquid ◽  
Nonlinear Surface ◽  
Isothermal Wall ◽  
The Stability

Representing surface tension by nonlinear relationship on temperature, the boundary value problem of linear stability differential equation on small perturbation is derived. Under the condition of the isothermal wall the effects of nonlinear surface tension on stability of heat transfer in saturated liquid film of different liquid low boiling point gases are investigated as wall temperature is varied.

scholarly journals Structural genomics approach to investigate deleterious impact of nsSNPs in conserved telomere maintenance component 1

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Arunabh Choudhury ◽  
Taj Mohammad ◽  
Nikhil Samarth ◽  
Afzal Hussain ◽  
Md. Tabish Rehman ◽  
...  
Keyword(s):  
Noncovalent Interactions ◽  
Md Simulations ◽  
Telomere Maintenance ◽  
Nucleotide Polymorphisms ◽  
Telomeric Dna ◽  
Congenital Diseases ◽  
Ob Fold ◽  
Significant Conformational Change ◽  
The Stability ◽  
The Impact

AbstractConserved telomere maintenance component 1 (CTC1) is an important component of the CST (CTC1-STN1-TEN1) complex, involved in maintaining the stability of telomeric DNA. Several non-synonymous single-nucleotide polymorphisms (nsSNPs) in CTC1 have been reported to cause Coats plus syndrome and Dyskeratosis congenital diseases. Here, we have performed sequence and structure analyses of nsSNPs of CTC1 using state-of-the-art computational methods. The structure-based study focuses on the C-terminal OB-fold region of CTC1. There are 11 pathogenic mutations identified, and detailed structural analyses were performed. These mutations cause a significant disruption of noncovalent interactions, which may be a possible reason for CTC1 instability and consequent diseases. To see the impact of such mutations on the protein conformation, all-atom molecular dynamics (MD) simulations of CTC1-wild-type (WT) and two of the selected mutations, R806C and R806L for 200 ns, were carried out. A significant conformational change in the structure of the R806C mutant was observed. This study provides a valuable direction to understand the molecular basis of CTC1 dysfunction in disease progression, including Coats plus syndrome.

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