Why <110> dumbbell in bcc iron has the lowest energy configuration ?

In non magnetic materials, is the lowest energy configuration and not SIA dumbbell. But, in bcc Iron dumbbell is the lowest energy configuration. What makes...

07 August 2018 5,113 3 View

Why MD simulation of mechanical loading (ex. tensile) in metallic systems gives stress values in GPa (high stress value) ?

During MD tensile simulation, the stress values rise upto some GPa (high stress value). I think it is because of the following reasons: 1. System is almost defect free or only with few defects...

07 August 2018 9,414 12 View

How is diffusion coefficient from MSD values obtained from LAMMPS is calculated ?

I'm interested in calculating the diffusion coefficient of self interstitial atom in iron system at 800 K. I got a plot like (attached) this 'MSD vs time' using LAMMPS. The slope (diffusion...

08 September 2017 1,625 24 View

Can any amorphous material be made into single crystal or into a crystalline form?

Amorphous crystal

01 January 1970 641 26 View

Martensitic transformation is considered as diffusionless shear transformation. How is shear involved in this transformation?

Diffusionless implies atoms have not moved. Then how come shear in this transformation of steel?

01 January 1970 801 3 View

What potential should be used for iron for studying dislocation crack grain boundaries interaction using molecular dynamics simulation ?

01 January 1970 3,466 6 View

In martensitic transformation in steel, why should we consider BCT by joining the face centered atoms of FCC even though FCC has higher symmetry?

FCC has 3 fold symmetry but BCT doesn't. So why should we draw a BCT inside a FCC and name it as martensite. A reverse can also be done where we can draw BCT and they get a FCC out of it. If so in...

01 January 1970 9,731 13 View

Why is the Ductile Brittle Transition Temperature of many metals (like silver) are not available ?

Why is the Ductile Brittle Transition Temperature of many metals are not available ? I was trying to find the DBTT data for silver and was shocked to know the lack of these data.

01 January 1970 6,366 1 View

What is the Relation between Grain Boundary and grains crystallography ?

what does it mean - "Fe sigma 3" symmetric tilt grain boundary ? I know about sigma. What is the plane and direction of the two grains and grain boundary ?

01 January 1970 5,962 7 View

How do cerium and magnesium addition help to convert Grey cast iron into speroidal grey cast iron during heat treatment?

Cerium and Magnesium addition are done duirng casting in GCI so that after heat treatment GCI is converted to SGI. How Mg and Ce are contributing to this change?

01 January 1970 5,157 10 View

Why Austenite grains in steel show much more twinning than ferrite grains?

It is oftentimes said to be a distinctive metallographic trait that differentiates a fully austenitic and a fully felly ferritic steel without etching that might distinguish between two. Why...

02 March 2021 728 2 View

What could be the reason for not having further low chi square value (better agreement) in my refinement result?

I have tried every combination of parameter changes and after that i have a poor chi square value. I can't get it lower any further. I know there have been a lot of discussion about Rietveld...

26 February 2021 8,480 3 View

How to replicate the well conditions of a crystal hit with 20%(w/v) isopropanol?

I had a crystal hit in a well with 0.1M HEPEs pH 7.5, 10%(w/v) PEG 4000, and 20%(w/v) isopropanol. Why is isopropanol in w/v here if it's just solvent? How do I recreate this well condition?

25 February 2021 9,761 1 View

Is there a way to tell based on appearance which protein crystal should diffract the best?

I have had unheard of success with protein crystallography lately from a super successful protein expression and purification batch. I have attained a lately reproducible vast amount of crystals...

09 February 2021 5,155 5 View

Electron density difference maps(Fo-Fc): what is the meaning of negative densities (red blobs)?

Dear community, As far as I understand, negative density features point at stuff that is in the model, but not supported by experimental data. However, in many cases (e.g. attached image), when...

06 February 2021 2,847 2 View

Should the Ice 1h crystalline structure be lost during equilibration process in LAMMPS?

I have created an Ice 1h structure and am equilibrating it 100K in NVT ensemble in LAMMPS for a timestep of 0.25fs in 3000 steps. The potential used is TIP4P/Ice. Although the simulation runs fine...

26 January 2021 9,603 11 View

Is there any list that contains which stiffness/elastic modulus(Cii,Cij) effect which plane or direction of a cubic system in what way?

The value of stiffness/elastic modulus(Cii,Cjj) affects crystallographic planes in many ways like maximum shear or maximum tensile stress when stress is applied. The anisotropic materials show...

23 January 2021 2,877 2 View

Why can I not find all of my residues in model predicted by Swiss-Model?

I am trying to perform homology modeling using the swiss-model but I have found that the swiss-model gives the same number of residues as that of the template. Whereas my sequence has more...

21 January 2021 5,568 3 View

What mathematics is needed to program quantum computers?

Quantum programming As we know, old computers work according to the rules of Boolean logic and classical set theory . On the other hand there is a discussion about quantum computers nowadays. If...

21 December 2020 275 4 View

How will DeepMind AlphaFold2 solution of the core problem of protein structure prediction from sequence impact biology and biophysics?

AF2 may most strongly impact experimental determination of protein structure by multiple methods with possible benefits and negative impacts over time. Some areas may need to quickly pivot or...

13 December 2020 6,026 5 View