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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27 views

Why is a hexagon such a stable shape for materials?

A hexagonal lattice is famously the shape of graphene, the source of the 2010 Nobel prize. The shape also shows up in beehives and in the basalt columns of Giant's Causeway in County Antrim. ...
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11 views

What material are screen protector films made of? [on hold]

To protect touch screens from scratches various plastic screen protector films are available for application on top of the actual screen. There are cheap vinyl ones and there are expensive tempered ...
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0answers
22 views

Activation energy as a function of defects

Electrical conductivity has a form of Arrhenius equation. It is assumed that activation energy decreases with defect density in the insulating state and becomes zero in the conducting state. Can one ...
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1answer
54 views

Energy conservation of permanent magnets engine

How to explain the fact that magnet can attract an object (apply a work W) without losing a (significant) part of its internal energy? How to apply the energy conservation principle? Please think to ...
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1answer
42 views

Working out the penetration of radioactive decay products

From my understanding of the products of radioactive decay (alpha particles, beta particles, and gamma are all I know of), the particles (or energy I guess?) are stopped by a medium according to it's ...
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1answer
53 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, ...
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0answers
28 views

What exactly is cutting with a knife will look like on the atomic scale? [duplicate]

Some times I like to view the world in the microscopic scale .ie. at this level all objects any thing will be collection of atoms which we normally don't view with our naked eye. At that scale I ...
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0answers
8 views

Is there any relation between single crystal elastic constants and plastic deformation?

The elastic constants are the tensor coefficient in Hook's Law. Which are valued only in elastic region.But, we are using elastic constants to find the hardness.The hardness is the measure of the ...
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0answers
10 views

absorption and reflection of sound on molecular level

Can someone explain the reflection and absorption of sound on the molecular level? What really is reflection? Why porous and soft material absorbs sound? What's the definition of soft in terms of ...
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1answer
25 views

What properties make a good catalyst?

Specifically, I am thinking about metal catalysts that do not (apparently) take part in a direct chemical reaction. Is there any general method of either finding a catalyst for a given chemical ...
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1answer
55 views

Why the tyres of vehicles are always found to be black? [closed]

Generally, it happens. I never seen vehicles with tyres of different color other than black..?
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1answer
43 views

Work out friction coefficient using the two material's properties

For a physics engine I am working on, I need to know two object's friction coefficient (for bouncing, collision detection, friction in general etc.). Since this physics engine will have lots of ...
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0answers
38 views

Structure of Metallic Hydrogen [migrated]

I am simply curious what the theoretical arrangement of metallic hydrogen would be. I found this article which gives a picture, but I don't understand what the labels mean (e.g. is H5 an isotope, ...
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1answer
34 views

Perovskite's material parameters?

Perovskite's material parameters? What are the major material parameters being investigated? [For example, water solubility, absorption characteristics, surface energy etc]
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37 views

Why do clothes look darker or change color when they get wet? [duplicate]

Clothes can look darker or change color when they get wet. Why does this happen?
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1answer
44 views

Linearity of thermal expansion of metals?

I am having to do a path length correction for a metal tube (stainless steel 316, 16ppm/C) from 0-100 degC. I need to correct to within approximately 1 ppm. How much do typical engineering metals ...
2
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1answer
36 views

Physical Constraints of Very Large Humanoids [closed]

I loved Godzilla movies when I was a kid (still do), but ever since Pacific Rim came out, I have been pondering just how implausible really large humanoids would be given the laws of physics. For the ...
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1answer
35 views

Mullins effect in the elastic material

I was thinking on a experimental question, but I couldn't get the answer: How can we measure how the Mullins effect influences in the pressure inside a balloon? (I mean that, if there is a formula, ...
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1answer
39 views

Does the magnetic anisotropy state only have two possible directions?

Wikipedia says "The magnetic moment of magnetically anisotropic materials will tend to align with an easy axis". Does this mean that it is completely impossible to orient the magnetic moment with any ...
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0answers
88 views

What would happen to a submarine coated in water repellent

I saw the article about laser-etched hydrophobic metal, and it got me thinking, how would a submarine function differently if coated as such? Would it move faster, sink completely, be unable to move ...
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1answer
64 views

How much weight would I need to put on the end of a tube to break it?

Say I have a tube with a circular cross-section made from some material (for an example, I'd like to use acrylic). I support it horizontally from one end and hang a weight from the other end. How ...
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1answer
35 views

Applications of partial differential equations in material science [closed]

I've been asked to find a partial differential equation that has applications in material science. However we are not allowed to use the heat equation. I have found Fick's laws (basically the heat ...
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0answers
14 views

Steel and aluminum fatigue limit

Is it true that steel has a fatigue limit? Is it true that past a certain number of stress strain cycles, steel will last indefinitely if its ultimate strength after the specified number of stress ...
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1answer
36 views

Plasma frequency

I have a neutral plasma and I need to solve Maxwell equations given the charge and current densities on the plasma. In order to do it I need to know the electrical permittivity $\varepsilon$, I've ...
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1answer
65 views

Relationship between electrical resistivity and density

I just read this answer on EE.SE and that triggered a doubt in me. If I were asked whether there is any relationship between the electrical resistivity and the density of a substance I'd answer ...
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0answers
29 views

Finding the strains from a 0, 90 rosette - Mohr's circle

I have used a strain rosette with two gauges at 0 and 90 degrees to find strain on a beam under force and an trying to plot Mohr's circle for the problem. As the gauges are at right angles finding the ...
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1answer
26 views

will my duraflex seams melt over a fire

Good day ladies and gentlemen, i do realize it may seem like a welding question but i assure you it is physics related. i have built a non pressurized boiler that contains water to be used over an ...
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0answers
55 views

Find the maximum allowable bending moment

A rolled steel universal I-section beam with a serial size of $406\times178$ has a mass of $60$kg/m. What is the maximum safe allowable bending moment this beam can sustain,given that the maximum ...
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1answer
30 views

Would it actually be possible to preserve a snow flake?

In episode one of season 3 of The Big Bang Theory Leonard offers Penny as a gift a snow flake he says he preserved in some kind of resin, having it brought from the North Pole. Is this purely ...
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11 views

Equivalence of Bulk Modulus Definitions [duplicate]

Per http://en.wikipedia.org/wiki/Bulk_modulus, $K=-V\frac{\mathrm d P}{\mathrm d V}$ and $K=\rho \frac{\mathrm d P}{\mathrm d \rho}$ are two equivalent definitions for $K$, the bulk modulus. How do ...
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2answers
40 views

Piezoelectric polarity

After a few days, I cannot find an answer to this question: Besides mechanical stress, is there another way to induce a negative charged surface on quartz? Note: several scholarly articles kept ...
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1answer
21 views

magnetostrictive effect due to earth's magnetic field

is there any magnetic field sensor,which produces stress or strain as output,when that sensor is sensing earth's magnetic field on the surface of earth(0.25 gauss to 0.65 gauss)?or any ...
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0answers
25 views

coherent grain growth

What is the driving force for growth of coherent precipitates in the matrix? The driving force for growth of incoherent precipitates in the matrix is concentration slope between tiny and large ...
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0answers
27 views

Martensitic transformation in ceramics

What is the specification of Martensite (displacive) transformation in ceramics comparing to yhe one in metals? I just know about Martensite transformation in metals. For example, these ...
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0answers
24 views

Does the surface of austenitic steels have an especially “dynamic” phase somewhere between 100 and 200 Celsius?

There is lots of kitchen lore about pans. One popular concept are the "pores" of a steel pan surface, which are the reason why food sticks to the pan when it's not heated properly. I don't know much ...
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0answers
24 views

How much will a round tube deflect under load? [closed]

I'm trying to determine the materials I need to complete a hobby project, and I'm having trouble estimating how much flex a given steel tube would have under different configurations/loads. My setup ...
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0answers
40 views

Applying Statistical Mechanics to Formulate Corrosion (Rusting)

I wanted to try and take my current knowledge of statistical mechanics (first quarter undergraduate course completed, beginning researcher in far from equilibrium statistical mechanics, basic ...
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2answers
802 views

what is difference between homogeneous vs isotropic material?

When we say a material is isotropic? When properties such as density, Young's modulus etc. are same in all directions. If these properties are direction dependent, then we can say that the material is ...
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0answers
12 views

What curved, transparent media exists for full-motion holograms?

Looking to project light either on, or through, but not from, a transparent medium. So I'm thinking of half a hollow sphere with a surface thickness of 1/10th the radius of sphere. A clear curved ...
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0answers
35 views

Material Evaporation in Low Pressure Condition

Are there any references for the determination of evaporation temperature of materials under low pressure condition? Specifically, I need to evaporate InP under low pressure at around 1.0 Torr which ...
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1answer
52 views

Drilling a Vault [closed]

Premise I think this is a Physics question, so i thought this would be the right stackexchange website to post my question. If I'm wrong, feel free to move the question in the right website. I'm not ...
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0answers
27 views

Like viscoelastic polymers, why there are not storage and loss moduli for cast iron?

Viscoelastic polymers have different paths upon loading and unloading, so there is energy dissipation, so they have storage and loss moduli. Plastic behavior is also shown by cast iron: loading and ...
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1answer
92 views

Theoretical limits to specific strength with hierarchical structures

Specific strength (measured in units of pressure/density or speed$^2$ which in MKS there is a proposal for labelling it as the Yuri (meter/second)$^2$) is defined as tensile strength divided by ...
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2answers
44 views

Are there materials with more than two states that can be used in circuit design? [closed]

Are there atoms or materials that have 3 or more states that can be used in circuit design? Can you provide any examples of such materials, and their possible applications to circuit design? And is ...
5
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1answer
68 views

Superhydrophobic coating and water friction

If you were to apply super-hydrophobic coating to the hull of ships or even submarines, would you get more or less water friction? If the coating completely repels the water you could argue there ...
0
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1answer
24 views

Stresses in materials depend on co-ordinate system of choice, true or not?

I was studying stresses and strains and my professor told me that they depend on the co-ordinate system we choose to represent, he also said that as we rotate the co-ordinate system, shears that were ...
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1answer
25 views

What is difference between anisotropy and inhomogeinity of this type of composite material?

I am studying some types of composite materials having 2 phases - fibers and matrix. I have some questions and confusions. Any help is appreciated. The composite has fiber along length and I am ...
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2answers
3k views

Melting diamond and cool down as diamond

Is it possible to melt diamond? And if possible while let it cool will it became diamond again?
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1answer
969 views

What common materials absorb most infrared light?

I'm competing in a simple robotics competition where most of the participants use reflected infrared light to detect their opponent. I'd like to make my own robot as difficult to see as possible. What ...
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1answer
39 views

Can I tear apart a pipe with magnetostriction? And how big field should I use?

As I know, with magnetostriction we can "stretch" its unit cell. The stronger is the field, the more it expands the cell. Using alternating current in coils that induce magnetic field we can stretch ...