Geometric transitions, non-Kahler geometries and string vacua

After a quick review of the wild structure of the complex moduli space of Calabi-Yau 3-folds and the role of geometric transitions in this context (the Calabi-Yau web) the concept of deformation equivalence for geometric transitions is introduced to understand the arrows of the Gross–Reid Calabi-Yau web as deformation-equivalence classes of geometric transitions. Then the focus will be on some results and suitable examples to understand under which conditions it is possible to get simple geometric transitions, which are almost the only well-understood geometric transitions both in mathematics and in physics.

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Wilson loops, geometric transitions and bubbling Calabi-Yau's

Journal of High Energy Physics ◽

10.1088/1126-6708/2007/02/083 ◽

2007 ◽

Vol 2007 (02) ◽

pp. 083-083 ◽

Cited By ~ 18

Author(s):

Jaume Gomis ◽

Takuya Okuda

Keyword(s):

Wilson Loops ◽

Geometric Transitions

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Efficient Modeling of Fretting of Blade/Disk Contacts Including Load History Effects

Journal of Tribology ◽

10.1115/1.1540125 ◽

2004 ◽

Vol 126 (1) ◽

pp. 56-64 ◽

Cited By ~ 29

Author(s):

H. Murthy ◽

G. Harish ◽

T. N. Farris

Keyword(s):

Frictional Contact ◽

Contact Region ◽

Singular Integral Equations ◽

Numerical Approach ◽

Design Tool ◽

Load History ◽

Near Surface ◽

History Effects ◽

Geometric Transitions ◽

Fretting Damage

Fretting is a frictional contact phenomenon that leads to damage at the contact region between two nominally-clamped surfaces subjected to oscillatory motion of small amplitudes. The region of contact between the blade and the disk at the dovetail joint is one of the critical locations for fretting damage. The nominally flat geometry of contacting surfaces in the dovetail causes high contact stress levels near the edges of contact. A numerical approach based on the solution to singular integral equations that characterize the two-dimensional plane strain elastic contact of two similar isotropic surfaces presents itself as an efficient technique to obtain the sharp near-surface stress gradients associated with the geometric transitions. Due to its ability to analyze contacts of any two arbitrary smooth surfaces and its computational efficiency, it can be used as a powerful design tool to analyze the effects of various factors like shape of the contact surface and load histories on fretting. The calculations made using the stresses obtained from the above technique are consistent with the results of the experiments conducted in the laboratory.

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