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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3
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23 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. ...
1
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1answer
91 views

Properties of “hard light”

According to this, and this, we now have the ability to make "light molecules", which, from my admittedly layman understanding, have something to do with rubidium atoms, vacuum, and temperatures near ...
4
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1answer
155 views

Why do neutron stars have solid crusts?

A long time ago I read that neutron stars have a solid crusts that are several orders of magnitude harder/stronger than alloys here on the Earth. So how is this possible ? A neutron star has a ...
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2answers
44 views

Electricity from something other than a solid

Is piezoelectricity only limited to solids or can liquids or non-Newtonian fluids create a current when compressed?
-2
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1answer
241 views

Is there any metal or any material that can survive the Sun? [closed]

If we were to send a unmanned spaceship through the Sun. What material can survive?
2
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1answer
230 views

What is the significance of the Debye temperature from a materials perspctive?

If I look at a table of different metals and their Debye temperatures, what does the variation in these temperatures tell me about these materials?
0
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1answer
41 views

Nomenclature “Material System”

This is just a quick question about nomenclature from General Relativity. Most textbooks refer to "material systems"; 1) Does a material system have to be a system with mass? or can it just be a ...
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0answers
24 views

Search strategies in Material Science

Material scientists often search for new materials with engineered properties. If, for example, you have a set of doped semiconducting materials with different doping levels, and you aim for maximal ...
0
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1answer
412 views

How are lattice parameters determined from reciprocal space maps?

It seems that the papers speak of reciprocal space maps with very high praise because of its ability to study strain in epitaxial films and determine the amount of relaxation. Also one can determine ...
3
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4answers
1k views

How to determine what an object is composed of?

Heads up: This question has never been asked (here) before the way I will ask it here, so let's shed some light on it a bit. Prelude and anecdote(can be skipped): The other day I was walking home, ...
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0answers
993 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 ...
0
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3answers
96 views

Is it possible to build planet-sized non-spherical structures?

Beyond certain size and density the celestial objects tend to admit a spherical size. I wonder if is there a fundamental mass, density or specific strength related number which when surpassed a non-...
2
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2answers
127 views

Why doesn't dielectric materials have coloured reflections like conductors?

I'm a 3D artist trying to learn the basic (or perhaps even intermediate) level of physics of photorealistic rendering. But most artist and tutorials on the internet have little to no clue of the ...
3
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0answers
115 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 ...
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1answer
979 views

Why are HCP materials brittle whie FCC materials are ductile?

Why are hexagonal close packed materials brittle, While face centered cubic is ductile. Is it related to crystal planes?
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1answer
28 views

Constant pressure, constant wall thickness, expanding volume = explosion?

Just been idly thinking about a gas cylinder I sometimes use. Pressure is about 200 Bar, or roughly 20 MPa. If I kept the same thickness of steel wall, and the same pressure, but made cylinders bigger ...
0
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2answers
82 views

How tall is the tallest Jell-O structure possible?

Given Jell-O with a particular consistency, how tall a structure could be built out of it before it collapses?
0
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0answers
33 views

is full spectrum transparency possible?

Are there materials fully transparent throughout the spectrum? (transparent to all frequencies). And if there's no such substance exists, is it even physically possible to design/make one?
2
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1answer
128 views

Heat Expansion of an Aluminium Ring with hole

I have a question of how aluminium will behave when heated ( I made a drawing below to explain the question) We have a ring of aluminium and a hole (green in drawing), if we heat the ring it will ...
0
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0answers
38 views

Can measurement of Spontaneous Magnetization and susceptibility lead one to deduce the magnetic structure of a magnetic compound?

For a given magnetic compound, spontaneous magnetization and susceptibility are measured at various temperatures (in this paper). (SMS measurement) From neutron diffraction data the compound is found ...
6
votes
2answers
690 views

Why is it easier to glide on sharp ice skates than on dull skates?

There have been previous questions (e.g. here and here) on Physics.SE about the mechanism that makes ice skating possible. Reviewing these, as well external references, it seems pretty clear that the ...
0
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0answers
24 views

Temperature bending stiffness of FR-4

I'm designing a PCB with metal over touch buttons. I have a colleague who want's to test the device reliability by building a tester that using pneumatic cylinders will test all the buttons. He's main ...
0
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1answer
55 views

Might a diamond with impurities (doped) be less brittle than a pure diamond?

Diamonds are extremely hard (resistant to pressure) but quite brittle (susceptible to shock). Sufficient impurity will compromise hardness, but I am finding it difficult to find out the effect on ...
1
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0answers
23 views

Why aren't most ionic/covalent/metallic materials self-healing?

For the most part, only soft-matter materials appear to possess self-healing capabilities (that is, if I cleave the material and then press the two halves together, the material re-forms) at room ...
0
votes
1answer
61 views

Is hysteresis essential for a memory system or material?

I want to know whether its essential for a memory system or material to have hysteresis between two of its variable ? If Yes, what can be the general relation of volatility of a memory with its ...
74
votes
5answers
11k views

Why wet is dark?

When something gets wet, it usually appears darker. This can be observed with soil, sand, cloth, paper, concrete, bricks ... What is the reason for this? How does water soaking into the material ...
2
votes
2answers
65 views

Is strain always relative to some initial state?

Let us say I am given a material with no knowledge about its history. Can I somehow calculate its strain ? Or a strain is always relative to some initial state (change in length/initial length) ?
2
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1answer
56 views

Why is GaN better than Si as a substrate for ZnO thin film?

in an attempt to grow a thin film using ZnO, I found many researches use silicon as a substrate and others use GaN. by further research I found that GaN is preferred than silicon but I don't know the ...
0
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1answer
75 views

Why does the stiffness of organic polymers (plastic) change so much with small changes in temperature?

This is on the borderline between Physics and Chemistry, but I would like a Physics perspective. I am guessing that plastics are a glass-like phase, rather than a true solid.
4
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1answer
219 views

Wall stress of a hexagonal pressure vessel

Problem: I want to calculate the stress in the walls of a hexagonal pressure vessel but I can't manage to get coherent results. For long vessels, cylinders are supposed to have the lowest hoop stress ...
1
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1answer
40 views

Why is metal stiffer at lower temperatures?

Each morning I cycle to school and lock my bike with a thick steel wire (about 8 mm thick). I noticed that it's much harder to change the shape of the wire in the morning when it's much colder than ...
4
votes
5answers
5k views

Graphene space elevator possible?

I just read this story on MIT working on industrial scale, km^2 sheet production of graphene. A quick check of Wikipedia on graphene and Wikipedia on space elevator tells me Measurements have ...
1
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3answers
277 views

Any scientific basis behind “crystal energy”? [closed]

I always hear people talking very loosely about the terms "vibration" and "energy" in relation to crystals. Is there any scientific basis in "crystal energy" or is it purely metaphysical ...
3
votes
5answers
55k views

Yield Strength versus Ultimate Strength

What is the qualitative difference between these two: As seen on the table Typical yield and ultimate strengths. I am trying to resolve the meaning of the phrase "contact yield stress" from C. ...
2
votes
2answers
373 views

Why is tearing paper irreversible?

Consider a piece of paper. If I pull on it in the right way it tears into two pieces. However, if I push those two pieces together, they do not spontaneously form a single piece. What happens at the ...
12
votes
3answers
3k views

Why are materials that are better at conducting electricity also proportionately better at conducting heat?

It seems like among the electrical conductors there's a relationship between the ability to conduct heat as well as electricity. Eg: Copper is better than aluminum at conducting both electricity and ...
2
votes
2answers
60 views

Quenching of binary alloy: Concentration equilibrium

I'm currently reading "Models for phase separation and their mathematics" by Paul C. Fife and there is a paragraph which I don't understand because I lack the necessary background in physics/...
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1answer
89 views

Flattest possible surface? [closed]

a) What is the flattest surface possible of any material? b) What is the flattest surface material available to humans at the present time?
0
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3answers
96 views

Physical properties of niobium pentoxide ($\mathrm{Nb}_2\mathrm{O}_5$) for thermal simulation

I am looking all day long for heat capacity, thermal conduction, and expansion coefficient of niobium-pentoxide. I want to conduct a thermal (heat flow) analysis on this and need it as input data. Can ...
2
votes
1answer
127 views

How to make electrical connection to silicon wafer for testing?

I am trying to make an electrical connection to a silicon wafer using a wire (approx 32AWG). I find that conventional lead/tin (60/40, no flux) solder cannot adhere well to the silicon wafer, since ...
0
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0answers
34 views

Equilibrium and constitutive relation

The constitutive stress-strain relation, say $\sigma=Y\epsilon$ where $Y$ is the Young's modulus, gives you stresses. At equilibrium, force balancing (say, with respect to a internal pressure $p$) ...
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0answers
31 views

Stress profile of pressurized bent shell

Consider a pressurized cylindrical shell of radius $r$ and pressure $p$, which at equilibrium has a nonvanishing in-plane stress components $pr/2$ and $pr$. This result is generically found by force-...
0
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0answers
40 views

Mooney-Rivlin coefficients sign

I'm doing a fitting of uniaxial compression data of a isotropic polymer using the Mooney-Rivlin model: $\sigma=\left( 2C_1 + \frac{2C_2}{\lambda} \right )\left( \lambda ^2- \frac{1}{\lambda } \right)$...
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0answers
28 views

Lower Threshold optical beam limiter?

We would like to implement a very fast beam limiting, so far google search shows that the common threshold ranges is in 1J/cm^2 or more, this could take seconds to activate as our laser ranges from 1 ...
0
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2answers
155 views

Does hardening reduce the ductility of a metal?

Is hardening equivalent with reducing the ductility of a metal and improving the yield strength of it?
11
votes
1answer
601 views

Why does plastic turn white in the area of stress?

There is a phenomenon with plastic in which it changes color to white in areas where stress is applied. When I bend a plastic rod the area in the centre, it turns white or loses colour. Why does this ...
3
votes
2answers
135 views

How does stress change through a bar that sharply increases in diameter?

I am looking to analyse the stress through the following bar: The bar is of circular cross section, homogeneous in material, that is of a certain diameter on one half, and a large diameter on the ...
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2answers
4k views

Can jet fuel melt steel beams? [closed]

Common sense suggests that steel beams should not yield under burning jet fuel without presence of other substances that produce very high temperatures when burning, such as thermite. So can jet fuel ...
0
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0answers
21 views

Flamant's use of mass and weight

I apologize for the stupid question, but I've consulted teachers and found their answers unsatisfactory. Professor E.Brune, in the XIX century, delivered a course on l'École des beaux-arts on ...
1
vote
1answer
376 views

Work functions of ceramics/insulators

Is anyone aware of or know of a good source or means of estimating the work function of a ceramic material? Typically, work functions are given for pure elemental metals, rather than for compounds, ...