Tracking the dissolution of calcite single crystals in acid waters: a simple method for measuring fast surface kinetics

2017 ◽  
Vol 19 (27) ◽  
pp. 17827-17833 ◽  
Author(s):  
Maria Adobes-Vidal ◽  
Harriet Pearce ◽  
Patrick R. Unwin
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Optical Microscopy ◽  
Single Crystals ◽  
Surface Kinetics ◽  
Simple Method ◽  
Modeling Approach ◽  
Finite Element Method Modeling ◽  
Kinetics Of ◽  
Acid Waters

A combined optical microscopy-finite element method modeling approach reveals the kinetics of proton attack on calcite.

Influence of Growth Temperature on the Evolution of Dislocations during PVT Growth of Bulk SiC Single Crystals

2007 ◽  
Vol 556-557 ◽  
pp. 263-266
Author(s):  
Sakwe Aloysius Sakwe ◽  
Peter J. Wellmann
Keyword(s):  
Optical Microscopy ◽  
Single Crystals ◽  
Growth Temperature ◽  
Growth Front ◽  
Growth Surface ◽  
Surface Kinetics ◽  
Step Structure ◽  
Temperature Regimes ◽  
Kinetics Of

In this paper we report, based on analysis of dislocation statistics, on the influence of growth temperature on the nucleation, propagation and annihilation mechanisms of dislocations. Using KOH defect etching and optical microscopy we have conducted dislocation tracking along lengths of crystals grown under various process temperature regimes to study their evolution and propagation mechanisms statistically. We further present the influence of growth temperature on the step structure of the growth front using AFM measurements. From the analysis of dislocation statistics and step structure in relation to temperature we derive the role of surface kinetics of the SiC gas species on the growth surface in dislocation evolution during PVT growth of bulk SiC.

A finite element method modeling approach for the development of metal/silicon nitride MEMS single-use valve arrays

2007 ◽  
Vol 17 (8) ◽  
pp. 1671-1679 ◽  
Author(s):  
Michelle L Cardenas ◽  
Andres M Cardenas-Valencia ◽  
Jay Dlutowski ◽  
John Bumgarner ◽  
Larry Langebrake
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Silicon Nitride ◽  
Modeling Approach ◽  
Finite Element Method Modeling ◽  
Single Use ◽  
Element Method

Microcompression Behaviors of Single Crystals Simulated by Crystal Plasticity Finite Element Method

2015 ◽  
Vol 46 (11) ◽  
pp. 4834-4840 ◽  
Author(s):  
Jae-Ho Jung ◽  
Young-Sang Na ◽  
Kyung-Mox Cho ◽  
Dennis M. Dimiduk ◽  
Yoon Suk Choi
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Single Crystals ◽  
Crystal Plasticity ◽  
Crystal Plasticity Finite Element ◽  
Element Method

Finite element method modeling of craniofacial growth

1985 ◽  
Vol 87 (6) ◽  
pp. 453-472 ◽  
Author(s):  
Melvin L. Moss ◽  
Richard Skalak ◽  
Himanshu Patel ◽  
Kasturi Sen ◽  
Letty Moss-Salentijn ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Craniofacial Growth ◽  
Finite Element Method Modeling ◽  
Element Method

A Finite Element Method Study of Combined Hydraulic and Thermal Autofrettage Process

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Rajkumar Shufen ◽  
Uday S. Dixit
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Residual Stresses ◽  
Surface Temperature ◽  
Hydraulic Pressure ◽  
Simple Method ◽  
Inner Surface ◽  
Set Up ◽  
Element Method ◽  
Autofrettage Pressure

Autofrettage is a metal working process of inducing compressive residual stresses in the vicinity of the inner surface of a thick-walled cylindrical or spherical pressure vessel for increasing its pressure capacity, fatigue life, and stress-corrosion resistance. The hydraulic autofrettage is a class of autofrettage processes, in which the vessel is pressurized using high hydraulic pressure to cause the partial plastic deformation followed by unloading. Despite its popularity, the requirement of high pressure makes this process costly. On the other hand, the thermal autofrettage is a simple method, in which the residual stresses are set up by first maintaining a temperature difference across the thickness of the vessel and then cooling it to uniform temperature. However, the increase in the pressure carrying capacity in thermal autofrettage process is lesser than that in the hydraulic autofrettage. In the present work, a combined hydraulic and thermal autofrettage process of a thick-walled cylinder is studied using finite element method package ABAQUS® for aluminum and SS304 steel. The strain-hardening and Bauschinger effects are considered and found to play significant roles. The results show that the combined autofrettage can achieve desired increase in the pressure capacity of thick-walled cylinders with relatively small autofrettage pressure. For example, in a SS304 cylinder of wall-thickness ratio of 3, an autofrettage pressure of 150 MPa enhances the pressure capacity by 41%, but the same pressure with a 36 °C higher inner surface temperature than outer surface temperature can enhance the pressure capacity by 60%.

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