scholarly journals Tomography-based characterization of ice-air interface dynamics of temperature gradient snow metamorphism under advective conditions

2015 ◽  
Vol 120 (12) ◽  
pp. 2437-2451 ◽  
Author(s):  
Pirmin Philipp Ebner ◽  
Christian Andreoli ◽  
Martin Schneebeli ◽  
Aldo Steinfeld
Keyword(s):  
Temperature Gradient ◽  
Interface Dynamics ◽  
Air Interface ◽  
Snow Metamorphism

scholarly journals Application of temperature gradient gel electrophoresis to the characterization of a nitrifying bioaugmentation product

2003 ◽  
Vol 43 (2) ◽  
pp. 277-286 ◽  
Author(s):  
Melissa A. Fouratt ◽  
Jeremy S. Rhodes ◽  
Charles M. Smithers ◽  
Nancy G. Love ◽  
Ann M. Stevens
Keyword(s):  
Temperature Gradient ◽  
Gel Electrophoresis ◽  
Gradient Gel Electrophoresis ◽  
Temperature Gradient Gel Electrophoresis

Characterization of Poly(2-vinylpyridine) by Temperature Gradient Interaction Chromatography

2006 ◽  
Vol 39 (9) ◽  
pp. 3466-3468 ◽  
Author(s):  
Soojin Park ◽  
Taihyun Chang
Keyword(s):  
Temperature Gradient

scholarly journals Vapor flux and recrystallization during dry snow metamorphism under a steady temperature gradient as observed by time-lapse micro-tomography

2012 ◽  
Vol 6 (5) ◽  
pp. 1141-1155 ◽  
Author(s):  
B. R. Pinzer ◽  
M. Schneebeli ◽  
T. U. Kaempfer
Keyword(s):  
Temperature Gradient ◽  
Physical Properties ◽  
Time Lapse ◽  
Phase Changes ◽  
External Temperature ◽  
Vapor Flux ◽  
Snow Metamorphism ◽  
Diffusion Enhancement ◽  
Micro Tomography ◽  
Snow Microstructure

Abstract. Dry snow metamorphism under an external temperature gradient is the most common type of recrystallization of snow on the ground. The changes in snow microstructure modify the physical properties of snow, and therefore an understanding of this process is essential for many disciplines, from modeling the effects of snow on climate to assessing avalanche risk. We directly imaged the microstructural changes in snow during temperature gradient metamorphism (TGM) under a constant gradient of 50 K m−1, using in situ time-lapse X-ray micro-tomography. This novel and non-destructive technique directly reveals the amount of ice that sublimates and is deposited during metamorphism, in addition to the exact locations of these phase changes. We calculated the average time that an ice volume stayed in place before it sublimated and found a characteristic residence time of 2–3 days. This means that most of the ice changes its phase from solid to vapor and back many times in a seasonal snowpack where similar temperature conditions can be found. Consistent with such a short timescale, we observed a mass turnover of up to 60% of the total ice mass per day. The concept of hand-to-hand transport for the water vapor flux describes the observed changes very well. However, we did not find evidence for a macroscopic vapor diffusion enhancement. The picture of {temperature gradient metamorphism} produced by directly observing the changing microstructure sheds light on the micro-physical processes and could help to improve models that predict the physical properties of snow.

scholarly journals Analysis of local ice crystal growth in snow

2016 ◽  
Vol 62 (232) ◽  
pp. 378-390 ◽  
Author(s):  
QUIRINE KROL ◽  
HENNING LÖWE
Keyword(s):  
Crystal Growth ◽  
Temperature Gradient ◽  
Mean Curvature ◽  
Driving Forces ◽  
Interface Velocity ◽  
Water Vapor Transport ◽  
Secondary Process ◽  
Theoretical Understanding ◽  
Vapor Flux ◽  
Air Interface

ABSTRACTThe structural evolution of snow under metamorphism is one of the key challenges in snow modeling. The main driving forces for metamorphism are curvature differences and temperature gradients, inducing water vapor transport and corresponding crystal growth, which is detectable by the motion of the ice/air interface. To provide quantitative means for a microscopic validation of metamorphism models, a VTK-based image analysis method is developed to track the ice/air interface in time-lapse μCT experiments to measure local interface velocities under both, isothermal and temperature gradient conditions. Using estimates of local temperatures from microstructure-based finite element simulations, a quantitative comparison of measured interface velocities with theoretical expressions is facilitated. For isothermal metamorphism, the data are compared with a kinetics and a diffusion limited growth law. In both cases the data are largely scattered but consistently show a mean curvature dependency of the interface velocity. For temperature gradient metamorphism, we confirm that the main contribution stems from the temperature gradient induced vapor flux, accompanied by effects of mean curvature as a secondary process. The scatter and uncertainties are discussed in view of the present theoretical understanding, the experimental setup and complications such as mechanical deformations.

Counterflow Rejection of Adsorbing Proteins for Characterization of Biomolecular Interactions by Temperature Gradient Focusing

2008 ◽  
Vol 80 (1) ◽  
pp. 172-178 ◽  
Author(s):  
Matthew S. Munson ◽  
J. Mark Meacham ◽  
Laurie E. Locascio ◽  
David Ross
Keyword(s):  
Temperature Gradient ◽  
Biomolecular Interactions ◽  
Temperature Gradient Focusing

Implementation and characterization of fiber Bragg gratings linearly chirped by a temperature gradient

1994 ◽  
Vol 19 (23) ◽  
pp. 2027 ◽  
Author(s):  
Jocelyn Lauzon ◽  
Simon Thibault ◽  
Jean Martin ◽  
François Ouellette
Keyword(s):  
Temperature Gradient ◽  
Fiber Bragg Gratings ◽  
Bragg Gratings
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