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A strained film grown on a vicinal substrate: Steps bunch or not to bunch?

Submitted by Zhenyu Zhang on
research
thin film epitaxy
roughening via step bunching

When a strained film is grown on a vicinal substrate, the steps advance like a train when the deposited atoms have sufficient mobility to reach the step edges. However, as the steps advance, the strain-induced force monopoles associated with the steps cause the steps to attract to each other (J. Tersoff, PRL 74, 4962, (1995)), resulting in a thermodynamic instability of the steps in the form of step bunching (J. Tersoff, et al., PRL 75, 2730 (1995)).

Manchester biophysics meeting --- DNA nanomachines

Submitted by Joseph X. Zhou on
research
biophysics conference

The 2-day conference of biophysics in Manchester had just finished recently. It is really a meeting with a tight schedule and lots of new stuffs.

The meeting took place in the new building of multi-decipline biocenter in Manchester University. One interesting speech was given by Prof. Andrew J. Turberfield 

How to represent the fiber-reinforced hyperelastic part

Submitted by mirende3yue on
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Hey guys,

I am right now doing a FEA on cervical spine, however, the annulus property is complex, and I need to represent it by a fiber-reinforced hyperelastic part, I tried a lot, but still are nowhere.

 Can anybody tell me how to assign some embeded layers with elastic rebar element to a solid part ?

Thanks a lot.

Numerical integration of non-polynomial functions

Submitted by Stephane Bordas on
research
integration; non polynomial; numerical

Hello colleagues,

 Would anybody know good references on numerical integration of non-polynomial functions? It would be enough for me to obtain one-dimensional rules. Of course, it could have impact for XFEM applications, but for another, improved XFEM method that we are developing.

Note  that I am not talking about integrating singularities, but non-polynomial functions. Examples:

sqrt(x)

cos(x)

sin(x)

product of these.

Thanks for any help,

 

Stephane

Any open source code to generate carbon nanotube cap?

Submitted by Damodara Reddy on
research
carbon nanotubes
Fullerenes

Generation of open ends carbon nanotubes coordinates (atomic positions) is easy and the generation of cap for these carbon nanotubes is extremely difficult. Some of the half-fullerenes (C60, C240, C540…) fit as a cap for the armchair and zigzag nanotubes. NanotubeModeler  (http://www.jcrystal.com/products/wincnt/index.htm) software generates the carbon nanotubes with cap but they are limited to few armchair and zigzag configurations.

PhD in Applied Mechanics

Submitted by nunziovitt on
research

Hi, guys...

I am a Mechanical Engineer (newly graduated).

Can somebody tell me where I can find a very good PhD studentship in APPLIED MECHANICS (i.e. vibro-acoustics, control systems, vehicle dynamics, etc...) in Europe?

I'm getting crazy with that... I hope somebody can help me.

 NV

  

Mechanics associated with grain-boundary diffusion and sliding in polycrystals and its application to nanocrystals

Submitted by Yujie Wei on
research
nanocrystalline materials
grain-boundary diffusion grain-boundary sliding
strain-rate sensitivity

As stated by Richard Vinci and Oliver Kraft in the announcement of 2008 Gordon Research Conference on Thin Film and Small-Scale Mechanical Behavior, there is a compelling need to understand the critical roles of different deformation mechanisms in structures with small characteristic dimensions, like nanocrystals and thin films. We have recently studied deformation behaviors in nanostructured materials and thin films with deformation mechanisms including grain-boundary diffusion, grain-boundary sliding, and grain-interior plasticity. Some interesting mechanical phenomena associated with heterogeneous grain-boundary properties are found and summarized here.

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