Questions tagged [material-science]

The study of how the properties of matter arise from its structure at all scales and of how processing can be used to modify those properties (often in pursuit of a specific application).

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11
votes
2answers
690 views

Force problem related to adhesive and bonding

I have two PCBs (printed circuit board), and they are glued by adhesives, as show in the pictures. And the location of the adhesives are indicated on the picture (please notice that NO adhesive is ...
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0answers
456 views

Why does the overhand knot jam but the figure-8 knot doesn't?

After tensioning a rope with an overhand knot in it, it is often very hard if not impossible to untie it; a figure-8 knot, on the other hand, still releases easily. Why is that so? Most "knot and ...
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0answers
1k views

Why is the AdS/CFT approach to superconductors rarely cited in condensed matter publications?

Let me put things into perspective by comparing with other applications of string theory. Nowadays review papers written by cosmologists about inflation models often discuss string theory scenarios ...
7
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1answer
190 views

Why don t tiny cracks heal in metal via cold welding?

Or in other words: how do cracks inside metal survive given the phenomenon of cold welding? If metal is overstretched, one or more fine cracks result along imperfections in the metal lattice. Why don'...
5
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0answers
104 views

Reference guide for standard descriptions of materials

Is there any reference that has a coherent list of materials and what type of approximate Hamiltonian to best describe them with (where it is known). Particularily I am looking for the following bits ...
5
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0answers
135 views

Can a bulk crystal have a spontaneous quadrupole moment?

Crystals of polar space groups e.g. ferroelectrics can have a spontaneous electric dipole moment. Is it possible for a crystal to have a spontaneous electric quadrupole moment (and higher order terms ...
5
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1answer
52 views

Is there a material with non-monotone density dependence on pressure?

Is there a material with such non-linear effects (including chemical reactions, phase transitions etc ...) so that there would be range where pressure increase would yield density decrease? What ...
4
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0answers
73 views

Difference between permittivities eps-opt and eps-inf?

Very often in materials physics we are interested in the relative permittivity at optical frequencies, which is usually denoted by $\varepsilon_\text{opt}$ or $\varepsilon_\infty$. But I'm confused ...
4
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0answers
148 views

What is the physical reason behind the negative differential resistance (NDR)?

As you know, there is an effect called negative differential resistance in some electric devices and materials, but I could not find any article or book or any other reference to talk about the ...
4
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0answers
659 views

How to know chern number of Massive Dirac Hamiltonian

I need your help. I consider this Hamiltonian $H=v(\xi k_y \sigma_x+k_x\sigma_y)+m\sigma_z $ $\xi$ is valley index. It is +1 (at K' valley) or -1 (at K valley ). I want to know Chern number of ...
4
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0answers
2k views

What does a sheet of graphene look like?

What does a sheet of graphene look like? At one atom thick, is it visible to the naked eye? Can it be handled (by hand) with being torn? Can it be felt at all? [Assuming a large enough sheet ...
4
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1answer
99 views

How can one reasonably theoretically model polycrystalline materials?

Many techniques are taught in advanced solid state courses but they are almost all derived for perfectly crystalline materials. For example, band structure really only appears theoretically when you ...
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0answers
55 views

Aerosol size distribution

When the size distribution of particles in an aerosol is obtained, there is always a bimodal distribution. The small peak accounts for the particles that are in sub-nanometer size range and the larger ...
3
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1answer
39 views

Effects of annealing on defects in solid

What is the effect of annealing on the defects present in the sample? Does it remove defects in the sample? Is there any chance that due to annealing the point defects present in the sample combine to ...
3
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1answer
148 views

Is there a way to inspect thin metal weld (2 mm - 3mm) by ultrasonic testing?

I am working with an ultrasonic device to inspect welds. So far, I have learned that the minimum thickness of the metal sheet for this inspection is 6mm - 8mm. But the product of mine has 3mm thick ...
3
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1answer
69 views

Why do the black balls floating on top of the water surface form lattice strctures?

The phenomenon I'm asking about can be seen in this veritusium video. The balls were just dumped in randomly, and they are buffeted by wind and currents, so how do they settle into clean lattice-like ...
3
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0answers
70 views

Stress-Strain behavior of ceramics at high temperatures

Can someone explain to me why do we observe the peak in the stress strain behavior at 1400 C and then a sudden decline followed by gradual increase? What does it signify? Does it have anything to do ...
3
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1answer
93 views

Issues with Miller indices

I have read that to find the intercepts of a plane represented by Miller indices is to take the reciprocal of each index. However, I noticed that does not give the original plane if we had to reduce ...
3
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0answers
313 views

Physics simulator to test the properties of metal alloys

In my free time I enjoy designing and invent random devices that do a variety of things and as part of this I design the materials that would be used to make the object, taking into account the needs ...
3
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0answers
58 views

Material that changes solubility when electric potential is applied

I am looking for a material witch is easy to deposit in thin films and which changes its solubility if a electric potential is applied. Do you know of any such materials ? EDIT: This is for what I ...
3
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0answers
96 views

Why do elastic bands stretch?

From what I know already rubber bands are made up of long straight molecules (alkanes I assume?) and when unstretched these are a mess of coiled and cross linked. And by stretching them you untangle ...
3
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0answers
1k views

What is so special about octahedral stresses?

Octahedral stresses are described here. Octahedral shear stress failure criterion is also called as distortion energy failure criterion. Moreover, famous von Mises yield criterion is related with ...
3
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0answers
439 views

can freezing water burst a short pipe if the pipe is open at both ends?

My question: If a thin-walled copper or brass pipe is open on both ends (let's dimension it at 60 cm long by 8mm inner diameter, as an example) and is filled with slightly salty water (estuarine ...
3
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0answers
4k views

Most rigid materials

Ordinary web searches are not turning up lists of the most rigid materials for me. I am interesting in finding out the relative rigidity of commonly available materials and how to measure that ...
3
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0answers
38 views

How do spongy substances crack or tear?

I read that there is a length (the Griffith critical crack length) beyond which cracks start to become self-propagating. If a crack in a sponge very quickly reaches a hole and stops propagating how do ...
3
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0answers
95 views

nano materials and material science

As a part of my major project I have taken plates of Al6061 samples and butt welded them with friction stir welding machine. During welding I have incorporated metal oxide Nano particles into weld ...
3
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0answers
40 views

How does flow rate affect plume dynamics and film properties in PLD?

So I use a home-built Pulsed Laser Deposition(PLD) system to deposit metal oxide thin films. I use a $ 248\ \mathrm{nm KrF}$ laser. I recently deposited two films under slightly different conditions. ...
3
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0answers
64 views

How “steady” are screw threads?

I have a setup whereby two stainless steel end caps screw into a similar tube about 100mm in length and 25mm internal diameter. Thread is fairly standard, and is finger tight. The question is: ...
3
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1answer
219 views

The Egg Smashing Tournament

My cousins and I have a annual egg breaking tournament. First, each of us gets a hard boiled egg. Then, in a bracket tournament style, a pair of us face off in an egg breaking round: one person holds ...
3
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0answers
581 views

What makes Obsidian edges sharper than other glass?

Obsidian is a volcanic glass with a reputation for being extremely sharp. Some surgeons use obsidian scalpels rather than high-quality steel surgical scalpels. At the same time, glass blades are used ...
3
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1answer
2k views

If we put diamagnetic material under strong electromagnet.Would the opposing magnetic fields strong enough to attract ferromagnetic materials?

Suppose we put a diamagnetic material (such as Bismuth or Pyrolytic Carbon) under a strong magnet (see image below). It would create opposing magnetic fields. Would the opposing magnetic field be ...
3
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0answers
49 views

What material could be used to study magnetic phase transitions in a college laboratory exercise?

I am working to develop a simple laboratory exercise in solid state physics to be conducted by fourth year students of physics. The idea of the exercise is for the student to get some experience in ...
3
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0answers
109 views

Why can thermal shocks damage/break materials?

When an object is heated a lot and then brutally cooled down or vice-versa, it can crack or even break spectacularly. What happens inside that makes it do that? Is it only because the hot core swells ...
3
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0answers
153 views

A physicists perspective on a material science/engineering problem

I am looking into some research that involves engineering and material science. As a physicists I wondered what other physicists would think of this problem and how they would approach it. Much of the ...
3
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0answers
113 views

Where does one find pair-correlation functions for various materials?

What is the canonical source for finding pair-correlation functions for atoms in various materials? I am interested in both numeric computations and experimental measurements (like might be obtained ...
3
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0answers
124 views

Does graphene actually remain strong for macroworld engineering?

I heard that people envision strong structural materials made out of graphene, but I heard it may weaken when being stack in layers. Is graphene viable for macroworld structural engineering or is it ...
3
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1answer
211 views

Why is BaTiO3 piezoelectric, but CaTiO3 not?

When BaTiO3 is cooled below the Curie point (120°C), the cubic structure changes slightly, so that $Ti^{4+}$ shifts by 0.006nm away from its position at the center of the cube. I don't know why this ...
3
votes
1answer
131 views

What ring weave disposition should be the most resistant against stabbing and/or how to determine it

In a website that I am studying so I can build a Chain Mail, I have found a page featuring a lot of different Ring Weaves to build them. I want to determine which one is the best to provide ...
3
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2answers
13k views

What would be the best material to reflect radio waves?

From what I could gather after a quick search on the internet, it would seem that any material can reflect or absorb RF waves but thickness matters. It's obvious that most parabolic dishes are made ...
2
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0answers
17 views

How do earthquakes of different strengths affect buildings of different heights?

Why is it that short buildings respond more to high frequency oscillations while tall buildings respond more to low frequency oscillations? I would assume that how they react is related to the natural ...
2
votes
1answer
27 views

Mesoscopic Bose-Einstein Condensate

Bose-Einstein condensates of molecules of a few daltons have been already created, so I was wondering: would making a Bose-Einstein condensate on a system of Quantum Dots, due to their properties, ...
2
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0answers
72 views

How is ECR (Electron Counting Rule) done in a structure?

I've been told how to apply the ECR to GaAs{001}(2×4) in my lectures but it makes no sense to me and I don't seem to be able to find any other sources that explain this. (This is a further question on ...
2
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0answers
26 views

Temperature at which object reaches maximum physical stability

So a random thought crossed my mind, I am not sure if it makes sense at all. I apologize for the very amateur question: is there a name for the specific temperature at which an object reaches an ...
2
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0answers
19 views

Why can't all plastics form electrets?

What property should a dielectric need to become an electret? At first, I though polar dielectrics formed electrets, but non polar dielectrics like polypropylene also form electrets. So what property ...
2
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0answers
33 views

What wears out a rubber sole of a shoe faster - sliding against dry or wet clay?

This question arises from my daily experience as a tennis player. I'm a novice to tribology. I couldn't quite come up with anything to answer that question. Any help? I know for certain that the ...
2
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0answers
265 views

What is an “As-grown crystal”?

I was going through a paper on a material. In that paper the authors mention "as-grown crystal". I tried looking for it on Wikipedia and searched it online but none of them tell what it is. So can ...
2
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0answers
39 views

When tyres skid on a dry road, is it because friction is too low or because the rubber is not strong enough?

All other things being equal, a car with wider tyres is less likely to skid on a dry road than one with narrower tyres. As answers on related topics have made clear, the simple formula $F=\mu N$ does ...
2
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1answer
51 views

Which configuration is better in terms of elastic stiffness?

Which one deforms more when subjected to the same torque? I am having trouble thinking about this mathematically and with equations. Don't know what to do...
2
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0answers
30 views

Are domain sizes in typical magnets always limited by magnetostatic energy? Or can there be a significant Kibble-Zurek effect?

Apparently, realistic ferromagnetic metals (e.g. pure iron) differ from Ising-like spin models in a number of ways. One of these is that realistic ferromagnets don't magnetize spontaneously, they ...
2
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0answers
160 views

Magnetic susceptibility

Currently I'm doing the simulation of Ising Model with Monte Carlo method. I got a curve which the magnetic susceptibility diverge (precisely due to finite size effect, it is not diverge but show the ...

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