scholarly journals Enhanced c-axis KTN beam deflector by compensating compositional gradient effect with a thermal gradient

OSA Continuum ◽  
2021 ◽  
Vol 4 (2) ◽  
pp. 665
Author(s):  
Yun Goo Lee ◽  
Chang-Jiang Chen ◽  
Annan Shang ◽  
Ruijia Liu ◽  
Ju-Hung Chao ◽  
...  
Keyword(s):  
Thermal Gradient ◽  
Compositional Gradient ◽  
Gradient Effect

A Theoretical Study of the Temperature Gradient Effect on the Soret Coefficient in n-Pentane/n-Decane Mixtures Using Non-Equilibrium Molecular Dynamics

2020 ◽  
Vol 45 (4) ◽  
pp. 319-332
Author(s):  
Xiaoyu Chen ◽  
Ruquan Liang ◽  
Yong Wang ◽  
Ziqi Xia ◽  
Lichun Wu ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Temperature Gradient ◽  
Thermal Gradient ◽  
Linear Response ◽  
Theoretical Study ◽  
Soret Coefficient ◽  
Thermal Gradients ◽  
Gradient Effect ◽  
Non Equilibrium Molecular Dynamics ◽  
Non Equilibrium

AbstractThe effect of the temperature gradient on the Soret coefficient in n-pentane/n-decane (n-C5/n-C10) mixtures was investigated using non-equilibrium molecular dynamics (NEMD) with the heat exchange (eHEX) algorithm. n-Pentane/n-decane mixtures with three different compositions (0.25, 0.5, and 0.75 mole fractions, respectively) and the TraPPE-UA force field were used in computing the Soret coefficient ({S_{T}}) at 300 K and 1 atm. Added/removed heat quantities (ΔQ) of 0.002, 0.004, 0.006, 0.008, and 0.01 kcal/mol were employed in eHEX processes in order to study the effect of different thermal gradients on the Soret coefficient. Moreover, a phenomenological description was applied to discuss the mechanism of this effect. Present results show that the Soret coefficient values firstly fluctuate violently and then become increasingly stable with increasing ΔQ (especially in the mixture with a mole fraction of 0.75), which means that ΔQ has a smaller effect on the Soret coefficient when the temperature gradient is higher than a certain thermal gradient. Thus, a high temperature gradient is recommended for calculating the Soret coefficient under the conditions that a linear response and constant phase are ensured in the system. In addition, the simulated Soret coefficient obtained at the highest ΔQ within three different compositions is in great agreement with experimental data.

Thermal gradient effect on helium and self-interstitial transport in tungsten

2021 ◽  
Vol 130 (21) ◽  
pp. 215904
Author(s):  
Enrique Martínez ◽  
Nithin Mathew ◽  
Danny Perez ◽  
Sophie Blondel ◽  
Dwaipayan Dasgupta ◽  
...  
Keyword(s):  
Thermal Gradient ◽  
Gradient Effect ◽  
Interstitial Transport

Laboratory duplication of comb layering in the Rhum pluton

1977 ◽  
Vol 41 (319) ◽  
pp. 323-336 ◽  
Author(s):  
Colin H. Donaldson
Keyword(s):  
Growth Rate ◽  
Thermal Gradient ◽  
Cooling Water ◽  
Layer Formation ◽  
Compositional Gradient ◽  
Essential Condition ◽  
Multiple Origins ◽  
Granular Crystals ◽  
Abrupt Changes ◽  
Rapid Removal

SummaryThe changes in olivine morphology and grain size upwards through comb-layered olivine eucrite and peridotite varieties of harrisite in the Rhum layered pluton are systematic, from abundant small granular crystals, to fewer and larger hopper crystals, to highly elongate branching crystals, which are preferentially elongate along the a axis and perpendicular to the plane of the layering. These changes have been reproduced in the laboratory by cooling water-bearing melts (P = 5 kb) of harrisite at 14 and 30 °/hr. These cooling rates represent maximum values for natural crystallization of comb-layered harrisite. Other experiments suggest that the oriented branching olivines in the rock crystallized at 30–50 °C supercooling. The results indicate that continuous, rather than abrupt, changes in the degree of supercooling and supersaturation of the magma can cause formation of comb layers. They also indicate that while field relations point to growth of most comb layers along a thermal gradient in the magma, this is not an essential condition for comb layer formation. Growth could be along a compositional gradient instead. During crystallization of a comb layer, both nucleation rate and the number of crystals suspended in magma close to the layer are essentially zero. Conditions initiating and terminating comb layer formation and the origin of the rapid vectorial crystallization are discussed. It is suggested that some comb layers could form without change in degree of supercooling, due to rapid removal of crystals suspended in the magma causing the enhanced growth rate and branching style of growth of the remaining crystals. Multiple origins of comb-layered rocks may therefore be possible.

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