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Questions tagged [granulated-materials]

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Calculating Pore Size from Permeability

I am building an experiment where one has a bed of sand on top of a porous plate. The pores allow air to be blown through the plate from the bottom but the pores must be sufficiently fine to not ...
Tom's user avatar
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8 votes
3 answers
883 views

Why do good materials operate in non-equilibirium conditions?

If we look at the majority of useful or industrial materials surrounding us, like metallic alloys, glasses, ceramics, or plastics, it is often the case that these materials went through really hard ...
YoussefMabrouk's user avatar
2 votes
2 answers
127 views

Computational modelling of sand pile

I'm currently working on a computational model of the way sand acts when being pushed around, say, by a bulldozer. Specifically, I'm trying to determine the dynamic equations which govern the way that ...
Tom's user avatar
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1 vote
1 answer
56 views

What determines if a transgranular or intergranular fracture is more likely to occur?

As an example, why does glass tend to break by means of intergranular fracture? My analysis so far led me to believe that the tendency can be related to the intermolecular bond strength in a given ...
Len's user avatar
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1 vote
1 answer
111 views

How do sand balls retain their integrity for so long?

A friend showed me how to make sand balls at the beach, like shown here on this YouTube video. We were both wondering how they managed to keep their shape way longer than any other sandcastle bits. I’...
U0001's user avatar
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0 votes
0 answers
26 views

Rotational energy in wheel and friction. Estimatiion of rubber loss

When an aeroplane wheel touches ground it goes from 0 rpm to say 800 rpm almost in an instant. Rotational inertia causes the wheel to glide on the asphalt and rubber is chipped off. How can I do an at ...
Lasse Karagiannis's user avatar
1 vote
1 answer
53 views

Using abrasive lapping, is it possible to make a perfectly round cylinder starting with imperfect cylinder(s)?

Centerless cylindrical lapping is a technique used to create a smooth and round cylinder through the use of microscopic abrasive compounds. My question is a chicken and egg problem, because it seems ...
user391339's user avatar
0 votes
0 answers
72 views

Is the Brazil Nut Effect quantitative?

The Brazil Nut Effect (a.k.a. granular convection) has a straightforward statistical mechanical interpretation as a system minimizing its free energy, at least qualitatively. What I wonder is whether ...
Yly's user avatar
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2 votes
1 answer
131 views

How does the structure factor reflect the characteristics of particle distribution?

The structure factor is defined as follows: $$S(\mathbf k)=\frac{1}{N}\sum_i\sum_je^{-\mathbf k\cdot\mathbf r_{ij}\sqrt{-1}}$$ It is related to the radial distribution function by Fourier transform: $$...
fan duan's user avatar
1 vote
1 answer
42 views

When pressing coffee, why does boiling water and coffee mixture appear to decrease after grounds are pressed to bottom?

When pressing coffee, why does total volume of boiling water and coffee appear to decrease after grounds are pressed to bottom?
Cecil Cole's user avatar
0 votes
1 answer
91 views

Settling effect of crumbs in food [duplicate]

What is the physical principle behind the following behavior: When left with the remainder of a bag of chips, or cookie crumbs, etc., when shaking this container, the smaller particles will settle to ...
Jason P Sallinger's user avatar
11 votes
1 answer
355 views

Why do random slabs stay dry in the rain? [closed]

The image below shows the slabbed area I can see from my work window Whenever it rains some of the slabs stay dry however, it is never consistent which ones. Can anyone explain why this happens to ...
Kingsley-James's user avatar
2 votes
1 answer
71 views

Is there a name for this phenomenon?

Imagine I have a cylindrical pipe closed on both ends with lids. I fill it with sand and compress the sand tightly. Now I hold the cylinder vertically and remove the bottom lid. The sand will counter ...
yathish's user avatar
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1 vote
0 answers
30 views

How to classify archimedean solid quasicrystal made by stacking spheres

I have two sphere packing structures (i.e. 3N-coordinates of each structure). One is rhombicosidodecahedron and the other one is truncated icosahedron. They are clearly distinguished when they are ...
Ji woong Yu's user avatar
2 votes
2 answers
965 views

Definition of granular material

I am doing a project on some properties of granular materials. I might have to face people who ask the definition of granular material. How can we define granular materials? One answer is "it is sand-...
fahd's user avatar
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0 votes
0 answers
419 views

Why valence electron to atom ratio affect stacking fault energy?

Wikipedia article on factors that affect the stacking-fault energy (SFE) of a material says: Another factor that has a significant effect on the SFE of a material and is very interrelated with ...
Mockingbird's user avatar
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1 vote
1 answer
1k views

Particles separation by shaking [duplicate]

In granulometry, say I have a tube with an heterogeneous mix of particles of different sizes (sand and stones, by instance). The tube is vertical in the usual gravity field and is placed in the air. ...
Neraste's user avatar
  • 113
2 votes
2 answers
254 views

Are there materials that strongly (macroscopically) vibrate under light of certain frequencies? If so why?

Picture an imperfect plane of loose particulate matter like sand or silt. Are there materials where if I shine light (not isotropically) on the plane I could get the particles to vibrate with large ...
Skyler's user avatar
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2 votes
1 answer
70 views

Suffocation in a granular medium

I read of a recent accident in Alberta in which three girls fell into an open bed truck carrying canola seeds and suffocated. In that situation would it have been possible to keep breathing by using ...
Ambrose Swasey's user avatar
2 votes
1 answer
5k views

formula for the angle of repose

If we make piles of sand or of sugar, they form cones; the maximum slope of the cones depends on the material. Is there a formula which gives this slope (or the angle of the cone), given some ...
Michele O.'s user avatar
0 votes
1 answer
63 views

Objects in granular medium

If a spherical object of certain radius and mass (let's say 10 ft, 3,000kg) is placed in a granular medium such as sand. How can you calculate the max depth to which the object would sink?
BigPic's user avatar
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12 votes
5 answers
3k views

Is there a definite boundary between a powder and a fluid?

Given a powder of solid substance what will happen if we make the granules smaller and smaller mechanically? Will this eventually make a liquid or gas from the powder? Can there be gaseous substanse ...
Anixx's user avatar
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