Questions tagged [materials-engineering]
Questions related to the design of materials (cost-effectiveness, functionality, fabrication procedures, etc.)
37
questions
2
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A problem to simulate the kinetic energy operator using some field going through a crystal
We know about a differentiation and integration operations and also other ones can be simulated by an analog way using electric circuits with operational amplifiers (here are articles of the ...
- 1,007
2
votes
0
answers
16
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Issue regarding self repeated .vasp structure of engineered graphite/graphene
When engineers the graphite and save it as.vasp format, it will give self periodically repeated structure. Still, the size of the cell is the same, but the structure repeated itself by huge numbers in ...
- 21
2
votes
1
answer
57
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vc-relax calculation on two-dimensional slab
Is performing only a relaxation calculation (calculation='relax') sufficient for geometrical optimization in conducting a density functional theory (DFT) study of ...
- 794
5
votes
1
answer
155
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Non-monotonic behaviour in calculation time with changing 'degauss' value of 'cold' smearing
"I conducted a convergence test for the degauss value in Quantum Espresso input with smearing = 'cold'.
The results, ...
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3
votes
1
answer
130
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At a particular K-point (Monkhorst Pack) grid, SCF calculation is not converging
During a convergence test of (MoS2 2x2x1) monolayer using Quantum ESPRESSO, I tried several K-point Monkhorst-Pack grids. According to my understanding, the calculation time and computational cost ...
- 794
3
votes
0
answers
44
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Energy corrections to be added in my DFT input of Quantum ESPRESSO for studying catalytic activity of MoS2 for hydrogen evolution reaction
While investigating 'catalytic activity of MoS2 (monolayer) in hydrogen evolution reaction', what are the energy corrections that I am supposed to add in the DFT input (using Quantum ESPRESSO) to get ...
- 794
3
votes
0
answers
62
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What is the efficiency of Nylon/Polyethylene artificial muscles? [closed]
The only other question in regards to this subject doesn't have a precise answer and it is more about actuators that directly convert electricity into mechanical force.
Nylon or polyethylene fibers, ...
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4
votes
1
answer
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Question on CPU timings and/or ratio resp. DLPNO-CCSD(T) and wB97X-2-D for protein of ca. 1M Da
Suppose one has a protein of about 1 million Da, and performs a DLPNO-CCSD(T)/def2-TZVPPD/AutoAux/AutoAux calculation, and then performs a wB97X-2-D/def2-TZVPPD/AutoAux/AutoAux calculation, both via ...
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3
votes
1
answer
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Why is strain rate used instead of absolute strain for modelling stress relaxation of a viscoelastic material using the Maxwell model?
I don't quite fully understand the derivation of the Maxwell model for prediction of stress relaxation for viscoelstic materials. usually the governing equation can be described in terms of strain ...
4
votes
0
answers
160
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Which researchers in electrical engineering do work related to DFT?
I would like to gain knowledge about how DFT calculations can be specifically used in the subject of electrical engineering. It would really help if people in the community can direct me towards ...
- 1,532
1
vote
0
answers
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ASE: Receiving error on implimenting ase cellpar_to_cell method [closed]
I am getting the following error while implementing ase cell method. I am not able to understand where is it going wrong, although I think it has to do something with the values I am getting for cell.
...
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4
votes
1
answer
168
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Given cell edge lengths and dihedral angles, calculate lattice vectors?
I am given a list of edges: [a, b, c] and dihedral angles: [alpha, beta, gamma]. Can we determine the lattice vector directions of this unit cell?
e.g Edge lengths: ...
- 339
2
votes
0
answers
23
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Does laser-induced graphene (LIG) stay functional after being extracted from the substrate? [closed]
So, I've seen some videos about laser induced graphene and its use as either a supercapacitor or as a low-voltage heater.
In this video the person only uses two electrodes on each end of the LIG tape ...
- 151
3
votes
1
answer
43
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Classifying a materials' type by chemical formula
I'm working on a Machine Learning project applied to the materials science field, but without having consolidated domain knowledge of the latter.
What I'm trying to figure out is the following: let's ...
- 445
3
votes
0
answers
34
views
Making a graphene based conductive ink [closed]
I want to make a graphene-based conductive ink with cyclohexanone pr terpinol as the solvent and ethyl cellulose as the binder. How can I do that?
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4
votes
1
answer
339
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How to map high symmetry points from primitive cell to conventional cell?
We usually plot electronic bands with the help of high symmetry points of the irreducible zone of primitive cell of particular material. But if we want to plot bands with conventional cell, we have to ...
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3
votes
0
answers
898
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Phase diagrams for stainless steels [closed]
A stainless steel is a ferritic alloy, in general, with a low carbon content and a Cr content equal to or greater than 10.5%. To study the phase transformations and heat treatments undergone by these ...
- 461
9
votes
1
answer
247
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How to find the Cauchy stress tensor in solids using ab-initio methods?
I want to find the Cauchy stress tensor in certain materials with ab initio methods. I already have the analytical form of my own definition of "energy" and "forces" (not from DFT),...
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7
votes
1
answer
918
views
How could I know the numbers of different atoms in Materials Studio?
I am building a model in the Materials Studio which includes many atoms, so I'd like to count the number of different atoms, is there any way to do that?
- 2,077
5
votes
0
answers
588
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Why calculation of coordination numbers from Element-specific RDFs (ASE) doesn't make sense? [closed]
The link to the trajectory is here.I am using the module and similar code of the ASAP calculator from ASE. The problem is as follows, the running Coordination Number doesn't match the number of atoms ...
- 989
4
votes
1
answer
290
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Martensitic transformation, start and finish temperatures
Searching about the microstructure of Cu-Ni-Zn alloys I came across this article (published 2017) which in its conclusion section says:
"It was observed that the starting and finishing ...
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5
votes
0
answers
33
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Linear combination of homogenized composite material [closed]
My research is on the structural optimization of fibre-reinforced composite material (transversely isotropic material). I am currently working on a homogenization method for attaining the effective ...
12
votes
2
answers
127
views
What are properties of interest for energy storage materials?
In the field of simulation for energy storage materials, there is always a gap between theoretical calculations and demand for experimentalists. What could be directly calculated from ab initio ...
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8
votes
2
answers
570
views
Mathematical models for the plastic region in the tensile test
The tensile test of a material consists of subjecting a standardized specimen to an increasing axial tensile stress until it breaks. During its performance in the laboratory, we can plot a stress-...
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7
votes
1
answer
237
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Is it possible to install thermo_pw on windows 10?
For research purpose, my team needs to use thermo_pw package for ab-initio simulations. But the issue we are running into is that we cannot find a way to install it on our computer. We are using ...
-4
votes
1
answer
134
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Has there been research on improving the strength of graphene-based materials?
I read that brittle materials tend to have an observed strength much less than its theoretical strength because they tend to have surface cracks and whatever tension is applied gets greatly magnified ...
- 487
5
votes
0
answers
48
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A doubt about extended dislocation [closed]
I wonder why this phenomenon occurs:
"Unlike unextended screw dislocations, the extended screw dislocations
define a specific slip plane, the {111} plane of the fault and it
will be constrained ...
- 415
3
votes
0
answers
69
views
Doubt in Raoultian and Henrian Standard State [closed]
$Si(liq)=Si_\text{(1 wt% Fe)}$
Can you describe what is going on here?All that they ask for is change in Gibbs free energy for the process.I am completely unable to figure why this particular model is ...
- 415
6
votes
1
answer
75
views
Where is this extra plane coming from?
Why are there solid lines drawn connecting the solid circles after twinning has taken place? Ideally, that explains a real plane, isn't it? But why are we going to get a plane out of nothing if we ...
- 415
8
votes
1
answer
99
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What are the possible applications of DIC (digital image correlation) in mechanical testing and the field of materials science?
I would like to know about possible applications of DIC in mechanical testing and the field of materials
science, when I search there is the general topics of DIC usages, but I would like to know ...
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2
votes
1
answer
131
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Would the increase in cost, of a double-sided whiteboard, make it worth it to engineer such a device?
I wonder whether or not it would be useful to design and construct a double-sided Whiteboard (i.e. the front and back sides can both be used)?
The cost of the Whiteboard product would increase, but ...
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12
votes
1
answer
292
views
How to explain Density Functional Theory results to an experimentalist?
When we present our Density Functional Theory simulation results e.g. lattice parameters, stacking fault energies, band gaps, etc. to people who are experimentalists then the very first question ...
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20
votes
5
answers
3k
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Artificial muscles and their efficiency
Most of the artificial muscles are based on either pneumatic power or nylon fibers being heated so they contract. These methods consume more energy than what can be utilized.
Likewise, in early days ...
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10
votes
0
answers
170
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How can I draw the energy bands for the first and second zones of Brillouin? Is it conductor or insulator? [closed]
I want to draw the energy ($E$) diagrams for a simple cubic cell of parameter $a$, where each atom provides two electrons for the almost free electron levels for planes [100], [110] and [111].
I ...
- 1,763
11
votes
2
answers
500
views
Separation of valence bands in transition metal dichalcogenides (TMDs)
The image below refers to a phenomenon that occurs in TMDCs (transition metal dichalcogenides) monolayers that allowed the development of valleytronics. Why are there separate bands of different ...
- 1,763
5
votes
1
answer
111
views
Has DFT helped in development of better solar materials?
I would like to pursue a Masters degree in Materials Science and more focused towards solar materials to make it more efficient and reducing the energy payback time.
I had taken this course and was ...
8
votes
0
answers
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How is the phase degradation of concrete modeled? [closed]
Acid attack in concrete is a problem in sewage structures.
The phases degrade with the pH change at different pH values. The conditions in sewers is complex: The presence of a combination of acids, ...
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