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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24 views

Armco iron B-H curves [closed]

I've been looking for B-H curves for Armco iron. I'd love to find one with good resolution. Does anyone know where you could acquire one? I've been looking in various Armco ingot supplieres but no ...
0
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1answer
39 views

Why can't we build a styrofoam 747?

What properties of materials explain why building the same structure at different scales requires materials of different densities and strengths? Consider an airliner, and flying models thereof at ...
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2answers
380 views

Does metal under low tension ever actually bend?

Let's assume something like a pair of tweezers, since that's strangely what led to this mental exercise. Does the metal ever actually permanently transform its shape? Stainless steel is fairly ...
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5answers
190 views

Is this a fundamentally relativistic phenomenon?

This question was inspired by some silliness in other threads but is independent of that silliness. Say that a train car sitting on a track is accelerated uniformly along its length if each point on ...
9
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1answer
278 views

What happened to this folded paper in a hydraulic press?

The video below apparently shows a man folding an A3 size piece of paper 7 times, putting it under the hydraulic press each time. After 7 folds, on the last press, the paper sort of explodes. What's ...
7
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1answer
151 views

Invariant polynomials of the Landau theory of phase transitions (crystal symmetry?)

I'm convinced I'm missing something so obvious but here goes Typically, one can define something like a "general" expansion of an order parameter, ${\boldsymbol \Gamma}$, up to 6th order as follows $...
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1answer
59 views

Why a balloon explodes by itself? [duplicate]

I was wondering why a balloon explodes after some time by itself with no specific reason. yesterday I was doing my chores and to my amazement the balloon far in the corner of house pop with no obvious ...
77
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9answers
14k views

Why does matter exist in 3 states (liquids, solid, gas)?

Why does matter on the earth exist in three states? Why cannot all matter exist in only one state (i.e. solid/liquid/gas)?
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1answer
58 views

Tabletop Synchrotron

When I was undergraduate student I asked to my proffesor why nobody has made a synchrotron machine with a superconducting circular wire and magnetic field to accelerate electrons properly and to ...
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0answers
33 views

Why is the moon white? [duplicate]

Why is the Moon white? What is it's geological composition and how does that relate to it's apparent "color"?
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0answers
15 views

Why are some plastics flexible at low temperatures and some not?

Is there any general predictors for the flexibility of plastics as the temperature drops?
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0answers
31 views

Thermistor is more sensitive than metals [closed]

Can anybody tell me, why a thermistor is much more sensitive at temperature variation than a metal?
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0answers
29 views

Pressure vessel analysis of transversely isotropic multilayer material

Suppose I have a transversely isotropic, hyperelastic material with known strain energy that is a fibrous composite. I am interested in an explicit formula for the displacements (so I can get the ...
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1answer
29 views

Are all FCC structures ductile?

Doing research on crystal structures and the effects of Ductile to Brittle transition at different temperatures. Results of this test proved aluminium to be a brittle structure, which I know to be ...
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2answers
32 views

Can we enhance a thermal gradient by combining a dark surface and a shiny surface with an external glass layer?

I refer to the article at this site: http://solarcooking.wikia.com/wiki/Solar_Kettle-Thermos_Flask As we know, dark surfaces absorb radiation (eg. solar water heater), while shiny surfaces reflect ...
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0answers
11 views

Do Body Centre Cubic Structures become more ductile when subject to higher temperatures or does it remain brittle?

Doing some research on crystal structures and if they experience brittle to ductile transition when subject to different temperatures. I am aware that BCC structures become very brittle at low ...
1
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1answer
52 views

Measuring speed of sound in a solid specimen

Let's say I have real-life specimens of isotropic solid materials I want to investigate some properties of. Through my setup I'm able to send mechanical wave pulses into one cylindrical bar of the ...
6
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2answers
869 views

Why do chocolate bars usually break at the cleavages?

Why do chocolate bars usually break at the cleavages? The chocolate bar is less thick at cleavages. How can we relate thickness and fracture point of chocolate bar?
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1answer
43 views

Does light influence transparency?

Let's consider this thought experiment: There is a sheet of a (more or less) transparent material. On one side of the sheet there are two light sources illuminating one spot on the sheet. The sources ...
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0answers
38 views

Why do the vines change their spinning direction? [closed]

Look at the vines holding onto the lattice. The "vine springs" change their spinning direction in the middle. Why? And how do they achieve this? (I notice that some vines fail to get in touch with ...
0
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1answer
12 views

Question about the way the inner stress in an axially loaded member is defined

When a member is in tension, such as in a tensile test of a piece of metal, its freebody-diagram would show a force of P in both directions. Why then is its internal stress not $\frac{2 \cdot P}{A}$? ...
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1answer
22 views

Adsorption of polar molecules

On any given surface, is there more adsorption if the molecules in a vapor are polar? For example, for a given (approximate) molecular weight would one expect more adsorption onto a surface by the ...
3
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0answers
43 views

The physics of an anvil [closed]

I am trying to understand how an anvil might best be made. An anvil requires two essential characteristics: enough hardness to not be deformed under the blows of the hammer, but as little rebound and ...
1
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0answers
40 views

Different ways to calculate the bulk modulus

I am trying to calculate the bulk modulus of unit cells of materials with trigonal or monoclinic structure using two different methods: -The first one is by fitting the changes of volume and energy ...
2
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0answers
30 views

Why do sponges work? [duplicate]

By "sponge" I mean anything used to suck up liquids from surfaces, such as kitchen towels etc. I assume capillary action is a factor, and also maybe surface area and surface energy. What are the ...
0
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1answer
26 views

How is a unidirectional lamina transversely isotropic?

What I don't understand specifically is that if there happen to be more fibers in the $x_2$ direction than the $x_3$ direction, wouldn't that make the material properties in those directions different?...
2
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2answers
42 views

Why do materials show plastic behaviour for large stress?

As the stress is increased, the strain increases proportionally up to elastic limit and the material regains its original dimension within elastic limit. When the stress is increased further the ...
1
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1answer
70 views

$16~\rm N/mm^2$ flexural strength

This question more relates to construction and architecture but I am sure it will not be the problem to ask and get a good answer here. If we have declared flexural strength of concrete of 16 N/mm2, ...
2
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1answer
46 views

Are hardness, strength and toughness of materials not the same thing in a way?

I had to look through several videos and re-read Wikipedia statements about these material properties several times before I could even begin to differentiate them. However, now that I have found out ...
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0answers
32 views

Effective medium approaches - Volume averaging vs homogenization?

In dealing with multiphase two phase systems as an effective medium there are two approaches that can be taken. Volume averaging and homogenization. Volume averaging is very intuitive, just take ...
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0answers
17 views

What is our most complete microscopic theory for the elastic-plastic transition point?

I suppose its all stated in the title. What is our most successful description of the microscopic behavior of material at the elastic-plastic transition point. My condensed matter physics prof was ...
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1answer
40 views

behavior of dissolved ionic compounds in an electric field

Consider the following setup - An open, insulating box is filled with distilled water, into which is dissolved a significant amount of pure NaCl. Two insulated lumps of conductor, one with a large ...
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0answers
95 views

Why should I discard a carafe if it has ever been heated empty? (Can thermal shock permanently weaken materials without causing them to fail?) [closed]

Related to "What pressure or tension occurs in a glass jar when I pour boiling water inside?" I just got a new coffeemaker, and one of the warnings in the manual states that you should discard the (...
0
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1answer
54 views

Predicting contact time and COR (coeff of restitution) for a cricket ball and pitch

For real world application, COR --> Bounce produced by pitch, for both spinners & seamers; Contact time --> grip provided by pitch, mainly for spinners Assuming cricket ball to be a sphere and ...
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0answers
38 views

What's “the” physical explanation of hysteresis in ferrimagnetic materials?

I am wondering what is "the" or "a" physical explanation of hysteresis in ferrimagnetic materials. From what I've read in wikipedia and Cullity's book, there is a simple physical explanation for ...
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4answers
57 views

Same equation, different meanings

I went into a physics classroom today and saw this equation written on the board: $$ E = \frac \sigma \epsilon $$ At first I thought it referred to the electric field $ E $ between 2 parallel plates ...
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1answer
79 views

Why are Brillouin zones for graphene and monolayers of transition metal dichalcogenides the same?

The geometrical model of graphene is the flat honeycomb lattice, so the Brillouin zone is also flat honeycomb lattice. However, monolayer of transition metal dichalcogenides is not flat as it consists ...
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2answers
680 views

Why is diamond transparent while graphite is not?

Diamond and graphite are both made of the same atom, carbon. Diamond has a tetrahedron structure while graphite has a flat hexagonal structure. Why is diamond transparent while graphite is not (at ...
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0answers
29 views

2D materials with isotropic Dirac cones

The celebrated material graphene has electrons which can be described by the simple 2D Hamiltonian $H = v_F \left( \sigma_x p_x + \sigma_y p_y \right)$, where $v_F$ is a Fermi velocity. Silicene, ...
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1answer
28 views

3D Bravais Lattices in terms of $\mathbb{Z}^3$

I am looking at the definitions of Bravais Lattice on Wikipedia and I find that I can describe many of them in terms of a mathematical lattice $\mathbb{Z}^3$. cubic $\mathbb{Z}^3$ body-centered ...
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0answers
12 views

Spectral Signature

I am interested in studying about spectral signature of various materials. I am working as an electronics engineer intern in a company which deals with Hyperspectral imaging. Working with spectral ...
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1answer
32 views

Thermodynamic / Thermal Property

What is the definition for (i) Thermodynamic Property & (ii) Thermal Property? What are the subtle distinctions in the Thermodynamic Properties and Thermal Properties? ...
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3answers
568 views

Can vinyl LPs store audio above 20kHz and can it be played back? [closed]

If, in the future, humans genetically engineered themselves to be able to hear frequencies significantly above 20kHz (say, up to 100kHz), would they find vinyl LPs a viable method of storing and ...
8
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4answers
110 views

Can a material made of a heavier isotope of an element become harder or stronger?

I was wondering if any experiments have been done to measure if there is a change in the hardness or strength of a material made solely of a heavier isotope of an element which is a constituent of the ...
0
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0answers
27 views

Looking for materials with specific magnetic properties

To begin with, I am not a native English speaker and have very limited knowledge regarding magnetism and want to apologize in advance for probable use of incorrect terms. In the picture, M ...
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0answers
15 views

How to measure the two-point function for two phase media?

Given some two phase media, consisting of a random mixture of materials A and B. how does one measure the two-point function? The one-point function is trivial to determine and can be done simply by ...
0
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1answer
38 views

why cracks are observed over time in stainless steel vessels? [closed]

We are using stainless steel vessels for long time. But most of the times the vessels made by the stainless steel material are get cracked on its edges. I guessed this would happen due to the ...
9
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0answers
118 views

Is there a database or a classification of High-temperature superconductors?

I was wondering if there exists a list with all (or most of) the High-$T_c$ superconductor materials. In particular I'd like to know if there are databases or review that classifies them by their ...
3
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1answer
76 views

Temperature dependence of magnetic domains

Does the size of magnetic domains depend on temperature ? Not able to find any papers on this subject, maybe because there is no such dependence...
2
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2answers
153 views

Elongation and tensile strength of rubber

I want to do some experiments on a neoprene rubber sheet (ex. supplier). When I went to order the sheet I was confused because the listed elongation and tensile strength for all sheet sizes (with ...