scholarly journals Ta'u and Ofu/Olosega volcanoes: The “Twin Sisters” of Samoa, their P, T, X melting regime, and global implications

2014 ◽  
Vol 15 (6) ◽  
pp. 2301-2318 ◽  
Author(s):  
Stanley R. Hart ◽  
Matthew G. Jackson
Keyword(s):  
Melting Regime

Epitaxial Growth Following Crystal Nucleation in Laser-Quenched Si Films on SiO2

2015 ◽  
Vol 1770 ◽  
pp. 67-72
Author(s):  
Vernon K. Wong ◽  
A. M. Chitu ◽  
A. B. Limanov ◽  
James S. Im
Keyword(s):  
Epitaxial Growth ◽  
Growth Model ◽  
Crystal Nucleation ◽  
Key Factors ◽  
Complete Melting ◽  
Melting Regime ◽  
Direct Growth ◽  
Crystal Core ◽  
Excimer Laser Irradiation ◽  
Si Films

ABSTRACTWe have investigated the solidified microstructure of nucleation-generated grains obtained via complete melting of Si films on SiO2 at high nucleation temperatures. This was achieved using a high-temperature-capable hot stage in conjunction with excimer laser irradiation. As predicted by the direct-growth model that considers (1) the evolution in the temperature of the solidifying interface and (2) the subsequent modes of growth (consisting of amorphous, defective, and epitaxial) as key factors, we were able to observe the appearance of “normal” grains that possess a single-crystal core area. These grains, which are in contrast to previously reported flower-shaped grains that fully make up the microstructure of the solidified films obtained via irradiation at lower preheating temperatures (and amongst which these “normal” grains emerge), indicate that epitaxial growth of nucleated crystals must have taken place within the grains. We discuss the implications of our findings regarding (1) the validity of the direct-growth model, (2) the nature of the heterogeneous nucleation mechanism, and (3) the alternative explanations and assumptions that have been previously employed in order to explain the microstructure of Si films obtained via nucleation and growth within the complete melting regime.

scholarly journals Characterization and Prediction of Texture in Laser Annealed NiTi Shape Memory Thin Films

2010 ◽  
Author(s):  
Gen Satoh ◽  
Y. Lawrence Yao ◽  
Xu Huang ◽  
Ainissa Ramirez
Keyword(s):  
Thin Film ◽  
Monte Carlo ◽  
Shape Memory ◽  
Grain Growth ◽  
Electron Backscatter Diffraction ◽  
Laser Crystallization ◽  
3 Dimensional ◽  
Shape Memory Properties ◽  
Melting Regime ◽  
Grain Growth Model

Thin film shape memory alloys are a promising material for use in micro-scale devices for actuation and sensing due to their strong actuating force, substantial displacements, and large surface to volume ratios. NiTi, in particular, has been of great interest due to its biocompatibility and corrosion resistance. Effort has been directed toward adjusting the microstructure of as-deposited films in order to modify their shape memory properties for specific applications. The anisotropy of the shape memory and superelastic effects suggests that inducing preferred orientations could allow for optimization of shape memory properties. Limited work, however, has been performed on adjusting the crystallographic texture of these films. In this study, thin film NiTi samples are processed using excimer laser crystallization and the effect on the overall preferred orientation is analyzed through the use of electron backscatter diffraction and x-ray diffraction. A 3-dimensional Monte Carlo grain growth model is developed to characterize textures formed through surface energy induced abnormal grain growth during solidification. Furthermore, a scaling factor between Monte Carlo steps and real time is determined to aid in the prediction of texture changes during laser crystallization in the partial melting regime.

Early basic magmatism in the evolution of Archaean high-grade gneiss terrains: an example from the Lewisian of NW Scotland

1987 ◽  
Vol 51 (361) ◽  
pp. 345-355 ◽  
Author(s):  
H. R. Rollinson
Keyword(s):  
Trace Element ◽  
Source Region ◽  
High Grade ◽  
Ocean Ridges ◽  
Layered Gabbro ◽  
Basic Magmatism ◽  
Melting Regime ◽  
High Grade Metamorphism ◽  
Tonalitic Gneiss ◽  
Common Parent

AbstractAmphibolite blocks from an Archaean (2.9 Ga) trondhjemite-agmatite complex in the Lewisian at Gruinard Bay have a varied trace element and REE content. Whilst some of the variability is attributable to element mobility during high-grade metamorphism and subsequent trondhjemite magmatism, it is for the main part considered to be a primary feature of the amphibolites. The observed trace element and REE chemistry is best explained in terms of source region heterogeneity and suggests a melting regime comparable with that beneath certain types of mid-ocean ridge. There are geochemical similarities between the amphibolites and the Lewisian layered gabbro-ultramafic complexes, and the two may represent the derivative liquid and associated cumulates respectively from a common parent magma. Thus there is a parallel between the processes which generated some Archaean amphibolites and layered gabbro complexes and those operating beneath modern ocean ridges. Hornblendite and amphibolite pods enclosed within tonalitic gneiss, also found as blocks in the agmatite complex, are geochemically distinct from the main group of amphibolites and are probably of calc-alkaline parentage.

Effects of the melting regime on the composition of the oceanic crust

1992 ◽  
Vol 97 (B13) ◽  
pp. 19749 ◽  
Author(s):  
Terry Plank ◽  
Charles H. Langmuir
Keyword(s):  
Oceanic Crust ◽  
Melting Regime
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