Mesoscopic Transport Effects in Electrocatalytic Reactions

2019 ◽  
Vol 25 (23) ◽  
pp. 91-102 ◽  
Author(s):  
Yvonne E. Seidel ◽  
Zenonas Jusys ◽  
Björn Wickman ◽  
Bengt Kasemo ◽  
R. Jürgen Behm
Keyword(s):  
Mesoscopic Transport ◽  
Transport Effects ◽  
Electrocatalytic Reactions

Insights into electrocatalysis by scanning tunnelling microscopy

2021 ◽  
Author(s):  
Xiang Wang ◽  
Yu-Qi Wang ◽  
Ya-Chen Feng ◽  
Dong Wang ◽  
Li-Jun Wan
Keyword(s):  
Scanning Tunnelling Microscopy ◽  
Surface Processes ◽  
Scanning Tunnelling ◽  
Tunnelling Microscopy ◽  
Electrocatalytic Reactions

This review summarizes the applications of scanning tunnelling microscopy in electrocatalysis, including the investigation of the electrocatalyst structures and the surface processes related to electrocatalytic reactions.

scholarly journals A critical look at the prediction of the temperature field around a laser-induced melt pool on metallic substrates

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yi Shu ◽  
Daniel Galles ◽  
Ottman A. Tertuliano ◽  
Brandon A. McWilliams ◽  
Nancy Yang ◽  
...  
Keyword(s):  
Laser Beam ◽  
Constant Velocity ◽  
Three Dimensional ◽  
Laser Beams ◽  
Poor Control ◽  
Metallic Substrates ◽  
Melt Pool ◽  
Mechanical Models ◽  
Transport Effects ◽  
Thermal Histories

AbstractThe study of microstructure evolution in additive manufacturing of metals would be aided by knowing the thermal history. Since temperature measurements beneath the surface are difficult, estimates are obtained from computational thermo-mechanical models calibrated against traces left in the sample revealed after etching, such as the trace of the melt pool boundary. Here we examine the question of how reliable thermal histories computed from a model that reproduces the melt pool trace are. To this end, we perform experiments in which one of two different laser beams moves with constant velocity and power over a substrate of 17-4PH SS or Ti-6Al-4V, with low enough power to avoid generating a keyhole. We find that thermal histories appear to be reliably computed provided that (a) the power density distribution of the laser beam over the substrate is well characterized, and (b) convective heat transport effects are accounted for. Poor control of the laser beam leads to potentially multiple three-dimensional melt pool shapes compatible with the melt pool trace, and therefore to multiple potential thermal histories. Ignoring convective effects leads to results that are inconsistent with experiments, even for the mild melt pools here.

scholarly journals The Knudsen Paradox in Micro-Channel Poiseuille Flows with a Symmetric Particle

2020 ◽  
Vol 11 (1) ◽  
pp. 351
Author(s):  
Ananda Subramani Kannan ◽  
Tejas Sharma Bangalore Narahari ◽  
Yashas Bharadhwaj ◽  
Andreas Mark ◽  
Gaetano Sardina ◽  
...  
Keyword(s):  
Flow Behavior ◽  
Direct Simulation Monte Carlo ◽  
Micro Channel ◽  
Confined Geometries ◽  
Rarefied Flows ◽  
Model Pore ◽  
Duct Geometry ◽  
Transport Effects ◽  
Non Local ◽  
Simulation Monte Carlo

The Knudsen paradox—the non-monotonous variation of mass-flow rate with the Knudsen number—is a unique and well-established signature of micro-channel rarefied flows. A particle which is not of insignificant size in relation to the duct geometry can significantly alter the flow behavior when introduced in such a system. In this work, we investigate the effects of a stationary particle on a micro-channel Poiseuille flow, from continuum to free-molecular conditions, using the direct simulation Monte-Carlo (DSMC) method. We establish a hydrodynamic basis for such an investigation by evaluating the flow around the particle and study the blockage effect on the Knudsen paradox. Our results show that with the presence of a particle this paradoxical behavior is altered. The effect is more significant as the particle becomes large and results from a shift towards relatively more ballistic molecular motion at shorter geometrical distances. The need to account for combinations of local and non-local transport effects in modeling reactive gas–solid flows in confined geometries at the nano-scale and in nanofabrication of model pore systems is discussed in relation to these results.

Hot electron transport effects in lead telluride

1976 ◽  
Vol 20 (11) ◽  
pp. 1089-1095 ◽  
Author(s):  
G.P. Carver ◽  
B.B. Houston ◽  
J.R. Burke ◽  
D.K. Ferry
Keyword(s):  
Electron Transport ◽  
Lead Telluride ◽  
Hot Electron ◽  
Transport Effects ◽  
Hot Electron Transport

Anomalous transport effects in the impedance of porous film electrodes

1999 ◽  
Vol 1 (9) ◽  
pp. 429-435 ◽  
Author(s):  
Juan Bisquert ◽  
Germà Garcia-Belmonte ◽  
Francisco Fabregat-Santiago ◽  
Albert Compte
Keyword(s):  
Anomalous Transport ◽  
Porous Film ◽  
Transport Effects
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