scholarly journals An in situ exploration of subsurface defect migration to a liquid water‐exposed rutile TiO 2 (110) surface by XPS

2020 ◽  
Author(s):  
M. H. Mesbah Ahmed ◽  
Robert H. Temperton ◽  
James N. O'Shea
Keyword(s):  
Liquid Water ◽  
Defect Migration ◽  
Subsurface Defect

scholarly journals In situ continuous visible and near-infrared spectroscopy of an alpine snowpack

2017 ◽  
Vol 11 (3) ◽  
pp. 1091-1110 ◽  
Author(s):  
Marie Dumont ◽  
Laurent Arnaud ◽  
Ghislain Picard ◽  
Quentin Libois ◽  
Yves Lejeune ◽  
...  
Keyword(s):  
Liquid Water ◽  
Near Infrared ◽  
Winter Season ◽  
Impurity Content ◽  
Saharan Dust ◽  
Infrared Range ◽  
Snow Surface ◽  
Surface Slope ◽  
Near Infrared Range

Abstract. Snow spectral albedo in the visible/near-infrared range has been continuously measured during a winter season at Col de Porte alpine site (French Alps; 45.30° N, 5.77° E; 1325 m a.s.l.). The evolution of such alpine snowpack is complex due to intensive precipitation, rapid melt events and Saharan dust deposition outbreaks. This study highlights that the resulting intricate variations of spectral albedo can be successfully explained by variations of the following snow surface variables: specific surface area (SSA) of snow, effective light-absorbing impurities content, presence of liquid water and slope. The methodology developed in this study disentangles the effect of these variables on snow spectral albedo. The presence of liquid water at the snow surface results in a spectral shift of the albedo from which melt events can be identified with an occurrence of false detection rate lower than 3.5 %. Snow SSA mostly impacts spectral albedo in the near-infrared range. Impurity deposition mostly impacts the albedo in the visible range but this impact is very dependent on snow SSA and surface slope. Our work thus demonstrates that the SSA estimation from spectral albedo is affected by large uncertainties for a tilted snow surface and medium to high impurity contents and that the estimation of impurity content is also affected by large uncertainties, especially for low values below 50 ng g−1 black carbon equivalent. The proposed methodology opens routes for retrieval of SSA, impurity content, melt events and surface slope from spectral albedo. However, an exhaustive accuracy assessment of the snow black properties retrieval would require more independent in situ measurements and is beyond the scope of the present study. This time series of snow spectral albedo nevertheless already provides a new insight into our understanding of the evolution of snow surface properties.

scholarly journals In situ study of defect migration kinetics in nanoporous Ag with enhanced radiation tolerance

2014 ◽  
Vol 4 (1) ◽  
Author(s):  
C. Sun ◽  
D. Bufford ◽  
Y. Chen ◽  
M. A. Kirk ◽  
Y. Q. Wang ◽  
...  
Keyword(s):  
Radiation Tolerance ◽  
Defect Migration ◽  
In Situ Study

Investigation of Liquid Water Distribution under Temperature Gradient in PEFC Using in-situ X-ray Visualization

2020 ◽  
Vol 98 (9) ◽  
pp. 27-35
Author(s):  
Takahiro Komiyama ◽  
Takashi Sasabe ◽  
Hiroshi Naito ◽  
Katsuyuki Kawamura ◽  
Toshiyuki Suzuki ◽  
...  
Keyword(s):  
Temperature Gradient ◽  
Liquid Water ◽  
Water Distribution ◽  
X Ray

Extracting Model Parameters and Paradigms From Neutron Imaging of Dead-Ended Anode Operation

2009 ◽  
Author(s):  
Jason B. Siegel ◽  
Anna G. Stefanopoulou ◽  
Serhat Yesilyurt
Keyword(s):  
Liquid Water ◽  
Front Propagation ◽  
Neutron Imaging ◽  
Model Parameters ◽  
Two Phase ◽  
Pde Model ◽  
Saturation Limit ◽  
Gravity Driven ◽  
Water Accumulation

In a PEMFC, feeding dry hydrogen into a dead-ended anode (DEA), reduces the overall system cost, weight and volume due to reduced need for a hydrogen-grade humidification and recirculation subsystems, but requires purging to remove the accumulated water and inert gas. Although the DEA method of operation might be undesirable due to its associated high spatial variability it provides a unique perspective on the evolution of the water accumulation in the anode. Sections of the channel nearest the inlets are significantly drier than those nearest the outlet as shown in the neutron imaging of a 53 cm2 PEMFC. This method allows in-situ visualization of distinct patterns, including water front propagation along the channels. In this paper we utilize neutron imaging of the liquid water distributions and a previously developed PDE model of liquid water flow in the GDL to (a) identify a range of numerical values for the immobile saturation limit, (b) propose a gravity-driven liquid flow in the channels, and (c) derive the two-phase GDL boundary conditions associated with the presence of liquid water in the channel.

In Situ Study of Defect Migration Kinetics and Self-Healing of Twin Boundaries in Heavy Ion Irradiated Nanotwinned Metals

Nano Letters ◽  
2015 ◽  
Vol 15 (5) ◽  
pp. 2922-2927 ◽  
Author(s):  
J. Li ◽  
K. Y. Yu ◽  
Y. Chen ◽  
M. Song ◽  
H. Wang ◽  
...  
Keyword(s):  
Heavy Ion ◽  
Self Healing ◽  
Twin Boundaries ◽  
Defect Migration ◽  
In Situ Study
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