Dynamic observations of vesiculation reveal the role of silicate crystals in bubble nucleation and growth in andesitic magmas

Lithos ◽  
2018 ◽  
Vol 296-299 ◽  
pp. 532-546 ◽  
Author(s):  
P. Pleše ◽  
M.D. Higgins ◽  
L. Mancini ◽  
G. Lanzafame ◽  
F. Brun ◽  
...  
2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Shalabh C. Maroo ◽  
J. N. Chung

Evaporation of a nanoscale meniscus on a nanostructured heater surface is simulated using molecular dynamics. The nanostructures, evenly spaced on the surface, are ridges with a width and height of 0.55 nm and 0.96 nm, respectively. The simulation results show that the film breaks during the early stages of evaporation due to the presence of nanostructures and no nonevaporating film forms (unlike a previous simulation performed in the absence of nanostructures where nonevaporating film forms on the smooth surface). High heat transfer and evaporation rates are obtained. We conclude that heat transfer rates can be significantly increased during bubble nucleation and growth by the presence of nanostructure ridges on the surface as it can break the formation of nonevaporating film. This causes additional chaos and allows the surrounding cooler liquid to come in contact with the surface providing heat transfer enhancements.


ChemInform ◽  
2003 ◽  
Vol 34 (42) ◽  
Author(s):  
Elena V. Shevchenko ◽  
Dmitri V. Talapin ◽  
Heimo Schnablegger ◽  
Andreas Kornowski ◽  
Oerjan Festin ◽  
...  

1993 ◽  
Vol 310 ◽  
Author(s):  
Toshihiko Tani ◽  
Zhengkui Xu ◽  
David A. Payne

AbstractPLZT thin layers were deposited onto various substrates by sol-gel methods, and crystallized under different conditions and substrate treatments. Relationships are given for the chemical characteristics of the substrate's surface and the preferred orientations which develop on heat treatment. A preferred (111) orientation always developed for perovskite crystallized on Pt layers which contained Ti on the surface. This was attributed to the formation of Pt3Ti and the role of heteroepitaxial nucleation and growth sites. In addition, a preferred (100) orientation was also obtained on unannealed Pt/Ti/SiO2/Si substrates which were free of Ti on the surface. This was attributed to self-textured growth with flat faces striving for minimum surface energy conditions. The results are discussed in terms of the importance of interfacial chemistry on the control of texture for crystallization of PLZT thin layers on coated substrates.


2021 ◽  
Vol 10 (1) ◽  
pp. 768-778
Author(s):  
Shaoqiang Meng ◽  
Xiaowei Ouyang ◽  
Jiyang Fu ◽  
Yanfei Niu ◽  
Yuwei Ma

Abstract Graphene (G) and graphene oxide (GO) have been shown to significantly improve the mechanical properties of cement-based materials. In this study, the effect of the G/GO on cement hydration was investigated. First, the zeta potential of G/GO in simulated solutions was tested, and the interaction between G/GO’s surface and Ca2+ was explored. Subsequently, scanning electron microscopy was used to observe the morphology of C–S–H nucleation and growth on the cement surface in the cement paste containing G/GO. Furthermore, XRD and TGA analyses were carried out on the hydration products of the sample. At last, isothermal calorimetry was applied to investigate the influence of G/GO on the early hydration of cement. The results showed that the addition of G/GO significantly accelerates C–S–H nucleation and growth on the cement surface. It is indicated that the high mobility ions derived by G/GO in the cement paste dominate the reason for the accelerated hydration of cement. The presence of G, especially GO, facilitates the mobility of ions, especially Ca2+, thus enhances the interaction between the cement surface and the ions. This strong interaction promotes the C–S–H nucleation and growth, and therefore, the hydration of the cement.


1992 ◽  
Vol 270 ◽  
Author(s):  
S. S. Sandhu ◽  
J. W. Hager

ABSTRACTMathematical equations have been formulated to guide an experimental effort to produce an open-celled mesophase pitch foam. The formulation provides an analytical description of homogeneous bubble nucleation and growth, diffusion of the blowing gas through the liquid to the bubble surface, and the average material thickness between bubbles. Implications of the formulation for the experimental production of mesophase pitch foam are discussed.


2018 ◽  
Vol 148 ◽  
pp. 123-132 ◽  
Author(s):  
M. Arul Kumar ◽  
M. Wroński ◽  
R.J. McCabe ◽  
L. Capolungo ◽  
K. Wierzbanowski ◽  
...  

2019 ◽  
Vol 123 (38) ◽  
pp. 23586-23593 ◽  
Author(s):  
Xiaolai Li ◽  
Yuliang Wang ◽  
Mikhail E. Zaytsev ◽  
Guillaume Lajoinie ◽  
Hai Le The ◽  
...  

2017 ◽  
Vol 18 (1) ◽  
pp. 324-330 ◽  
Author(s):  
Suyue Chen ◽  
Jesse L. Carey ◽  
David R. Whitcomb ◽  
Philippe Bühlmann ◽  
R. Lee Penn

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
Brian R. Novak ◽  
Edward J. Maginn ◽  
Mark J. McCready

Heterogeneous bubble nucleation was studied on surfaces having nanometer scale asperities and indentations as well as different surface-fluid interaction energies. Nonequilibrium molecular dynamics simulations at constant normal stress and either temperature or heat flux were carried out for the Lennard–Jones fluid in contact with a Lennard–Jones solid. When surface defects were of the same size or smaller than the estimated critical nucleus (the smallest nucleus whose growth is energetically favored) size of 1000–2000Å3, there was no difference between the defected surfaces and atomically smooth surfaces. On the other hand, surfaces with significantly larger indentations had nucleation rates that were about two orders of magnitude higher than the systems with small defects. Moreover, nucleation was localized in the large indentations. This localization was greatest under constant heat flux conditions and when the solid-fluid interactions were weak. The results suggest strategies for enhancing heterogeneous bubble nucleation rates as well as for controlling the location of nucleation events.


Sign in / Sign up

Export Citation Format

Share Document