Role of surface energy in the heating mechanism of high explosives (HE) under shock effects

1982 ◽  
Vol 17 (5) ◽  
pp. 581-583
Author(s):  
E. G. Baranov ◽  
O. N. Oberemok ◽  
E. A. Semenyuk
Keyword(s):  
Surface Energy ◽  
High Explosives ◽  
Heating Mechanism

scholarly journals Dynamics of Monolayer Growth in Vapor–Liquid–Solid GaAs Nanowires Based on Surface Energy Minimization

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1681
Author(s):  
Hadi Hijazi ◽  
Vladimir G. Dubrovskii
Keyword(s):  
Surface Energy ◽  
Continuous Process ◽  
Vapor Liquid Solid ◽  
Gaas Nanowires ◽  
Monolayer Growth ◽  
Surface Energetics ◽  
Monolayer Expansion ◽  
Vapor Liquid Solid Growth ◽  
Vapor Liquid

The vapor–liquid–solid growth of III-V nanowires proceeds via the mononuclear regime, where only one island nucleates in each nanowire monolayer. The expansion of the monolayer is governed by the surface energetics depending on the monolayer size. Here, we study theoretically the role of surface energy in determining the monolayer morphology at a given coverage. The optimal monolayer configuration is obtained by minimizing the surface energy at different coverages for a set of energetic constants relevant for GaAs nanowires. In contrast to what has been assumed so far in the growth modeling of III-V nanowires, we find that the monolayer expansion may not be a continuous process. Rather, some portions of the already formed monolayer may dissolve on one of its sides, with simultaneous growth proceeding on the other side. These results are important for fundamental understanding of vapor–liquid–solid growth at the atomic level and have potential impacts on the statistics within the nanowire ensembles, crystal phase, and doping properties of III-V nanowires.

Preferred Orientations for Sol-Gel Derived Plzt Thin Layers

1993 ◽  
Vol 310 ◽  
Author(s):  
Toshihiko Tani ◽  
Zhengkui Xu ◽  
David A. Payne
Keyword(s):  
Heat Treatment ◽  
Surface Energy ◽  
Sol Gel ◽  
Nucleation And Growth ◽  
Thin Layers ◽  
Energy Conditions ◽  
Chemical Characteristics ◽  
Interfacial Chemistry ◽  
Si Substrates

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.

Phase Stability of Rare-Earth Based Mixed Oxides in Nano-Regime: Role of Synthesis

2010 ◽  
Vol 653 ◽  
pp. 131-152
Author(s):  
Rakesh Shukla ◽  
A.K. Tyagi
Keyword(s):  
Rare Earth ◽  
Surface Energy ◽  
Mixed Oxides ◽  
Metastable Phase ◽  
Chemical Route ◽  
Phase Stabilization ◽  
Metastable Compounds ◽  
Enhanced Stability ◽  
Soft Chemical Route

Synthesis plays an important role in the phase stabilization of unusual compounds. Of late, preparation of metastable compounds has gained a tremendous momentum due to unusual properties exhibited by them. In this article, we will discuss how by mere change in certain parameters of the reaction a metastable phase can be isolated using a soft chemical route. Surface energy induced stabilization are also observed wherein enhanced stability of the mixed oxides are observed in the nano-regime of the compound.

Patterning PETN and HMX using Dip Pen Nanolithography

2005 ◽  
Vol 896 ◽  
Author(s):  
Omkar Nafday ◽  
Brandon Weeks ◽  
Jason Haaheim ◽  
Ray Eby
Keyword(s):  
Surface Energy ◽  
Scanning Probe Microscopy ◽  
Convenient Method ◽  
Energetic Materials ◽  
Scanning Probe ◽  
Pentaerythritol Tetranitrate ◽  
High Explosives ◽  
Shock Initiation ◽  
Effect Of Surface ◽  
Dip Pen Nanolithography

AbstractRecently there has been a focused effort to develop reliable nanoscopic writing and reading capabilities. Dip-pen nanolithography (DPN) has emerged as a convenient method to deliver nanoscale materials onto a substrate by leveraging scanning probe microscopy capability. A new application for the DPN method is the field of microdetonics which is the microscale decomposition and study of reactions of explosives. Results are presented for patterning pentaerythritol tetranitrate (PETN) and cyclotetramethylene tetranitramine (HMX) on silicon and mica substrates. The ultimate goal is to pattern both energetic materials in nanoscale registry and investigate their reaction and decomposition at the nanoscale due to heating or shock initiation. In addition to patterning of high explosives, a discussion on the effect of surface energy on patterning rates is investigated. This knowledge will be applicable to inks beyond high explosives.

Role of surface energy in the initial sintering period

1969 ◽  
Vol 8 (11) ◽  
pp. 882-885
Author(s):  
P. S. Kislyi ◽  
M. A. Kuzenkova
Keyword(s):  
Surface Energy

The role of membrane surface energy on direct contact membrane distillation performance

Desalination ◽  
2013 ◽  
Vol 323 ◽  
pp. 22-30 ◽  
Author(s):  
Ludovic F. Dumée ◽  
Stephen Gray ◽  
Mikel Duke ◽  
Kallista Sears ◽  
Jürg Schütz ◽  
...  
Keyword(s):  
Surface Energy ◽  
Direct Contact ◽  
Membrane Surface ◽  
Membrane Distillation ◽  
Direct Contact Membrane Distillation

scholarly journals Adhesive interactions of geckos with wet and dry fluoropolymer substrates

2015 ◽  
Vol 12 (108) ◽  
pp. 20150464 ◽  
Author(s):  
Alyssa Y. Stark ◽  
Daniel M. Dryden ◽  
Jeffrey Olderman ◽  
Kelly A. Peterson ◽  
Peter H. Niewiarowski ◽  
...  
Keyword(s):  
Surface Energy ◽  
Interfacial Energy ◽  
Substrate Surface ◽  
Energy Calculations ◽  
Bioinspired Design ◽  
Interfacial Energies ◽  
Normal Adhesion ◽  
Adhesive Interactions ◽  
Low Shear

Fluorinated substrates like Teflon ® (poly(tetrafluoroethylene); PTFE) are well known for their role in creating non-stick surfaces. We showed previously that even geckos, which can stick to most surfaces under a wide variety of conditions, slip on PTFE. Surprisingly, however, geckos can stick reasonably well to PTFE if it is wet. In an effort to explain this effect, we have turned our attention to the role of substrate surface energy and roughness when shear adhesion occurs in media other than air. In this study, we removed the roughness component inherent to commercially available PTFE and tested geckos on relatively smooth wet and dry fluoropolymer substrates. We found that roughness had very little effect on shear adhesion in air or in water and that the level of fluorination was most important for shear adhesion, particularly in air. Surface energy calculations of the two fluorinated substrates and one control substrate using the Tabor–Winterton approximation and the Young–Dupré equation were used to determine the interfacial energy of the substrates. Using these interfacial energies we estimated the ratio of wet and dry normal adhesion for geckos clinging to the three substrates. Consistent with the results for rough PTFE, our predictions show a qualitative trend in shear adhesion based on fluorination, and the quantitative experimental differences highlight the unusually low shear adhesion of geckos on dry smooth fluorinated substrates, which is not captured by surface energy calculations. Our work has implications for bioinspired design of synthetics that can preferentially stick in water but not in air.

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