# Talk:Angle of repose

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## Food engineering

Angle of repose has great importance in food engineering, especially that deals with grain material storage and handling in large amounts in chutes.

I hear it may have some significance to archaeology as well: most minor pyramids in Egypt were built at an angle of 43° from the horizontal, which is the angle of repose for sand. Many of those built at the higher angle of 54° ended up collapsing.thefamouseccles

## Formula for spheres

Is there a formula relating the angle of repose to the coefficient of friction for homogeneuous spheres? I recall seeing such a formula, but cannot find it now.

## angle of repose/angle of friction

Angle of repose (α) is not the angle of friction (φ).

The former is as described the angle at which granular particles come to rest in a pile.

The latter is a function of normal and shear stress.

There is a relationship between the two: α = 45 deg + φ/2. —Preceding unsigned comment added by Mistersumner (talkcontribs) 18:48, 12 June 2008 (UTC)

## Reference concrete slump test

This seems to be relevant to the Concrete slump test, although concrete is not a single granular material. Should there be a reference? Campingcar (talk) 09:11, 29 September 2008 (UTC)

## Mystery?

I was under the impression that there was a mystery relating to the angle of repose. In particular, that if you take a pile in a container and remove the walls, you get one angle; if you pour a pile from the ground up with no walls you get the same angle. At its face, that's not surprising, but I remember hearing that the density distribution is different in these cases, suggesting some different internal structure, even though the angle of repose is the same. Is this just some silly pop-"science" thing or is this an actual unsolved problem? —Ben FrantzDale (talk) 02:34, 7 January 2009 (UTC)

## Spanish Version

The spanish version of Angle of repose is Ángulo de reposo. I'm new at this so I don't know how to change it but I hope someone can change it. The link now is connecting Angle of repose (in english) to the friction angle (in spanish, ángulo de rozamiento interno). Thanks! Cosiampirulo (talk) 21:30, 23 August 2011 (UTC)