Opened 13 years ago

Closed 13 months ago

# Particle Mesh Size units

Reported by: Owned by: Bruce Simons major help sieve mesh "particle size"

Much soil sampling and geochemistry data uses particle mesh sieves to sort the sample and catagorises the fraction by the "mesh size" (see eg http://en.wikipedia.org/wiki/Mesh_(scale), http://www.azom.com/details.asp?ArticleID=1417. The UCUM standards at http://aurora.regenstrief.org/~ucum/ucum.html specify a "mesh" value "mesh lineic number [mesh_i][MESH_I][in_i]" but this does not appear to be related.

Is there an appropriate "mesh" unit available in UCUM?

### comment:1 follow-up:  2 Changed 13 years ago by Gunther Schadow

This is similar to Gauge scales. Please provide a conversion function and a proposal for a unit symbol, then we could add this. If it's just some ordinal scale, then it would not need a unit.

### Changed 13 years ago by Bruce Simons

Table showing various mesh sizes

### comment:2 in reply to:  1 Changed 13 years ago by Bruce Simons

This is similar to Gauge scales. Please provide a conversion function and a proposal for a unit symbol, then we could add this. If it's just some ordinal scale, then it would not need a unit.

The only UCUM reference I can find is to gauge of catheters: Charrière, french gauge of catheters Ch [Ch] [CH] no 1 mm/[pi]

I understand from the attached table that the Mesh Size is a different unit of measure.

### comment:3 Changed 13 years ago by Simon Cox

On further investigation, I believe that Lineic number is correct. It is defined as inverse length - i.e. number per unit length. I think all mesh numbers are a scaled inverse-length, so are a lineic number. It just requires the scale factor to be determined.

### comment:4 Changed 12 years ago by Gunther Schadow

Could be inverse length or inverse circumference or even more complicated. I have once tried to understand needle gauge numbers but had to give up because I could not find a clear definition. This will go into UCUM almost automatically as soon as someone can research a formula -- however complicated -- that relates these gauges or mesh sizes to a standard unit in some way.

### Changed 12 years ago by Simon Cox

Spreadsheet of seive openings mapped to various seive number designations (taken from the other attachment)

### comment:5 Changed 12 years ago by Simon Cox

The attached spreadsheet shows that the seive designations are not a strict Unit of Measure, as the relationship between numbers and opening size cannot be expressed as a formula. The British scale is close - (British seive number) = 15300/opening(expressed in um)

but in general seive numbers are an ordered-nominal scale, nit a unit-of-measure.

### comment:6 Changed 9 years ago by Gunther Schadow

Thank you, Simon, do you move to reject this? It is your area of expertise much more than mine.

### comment:7 Changed 8 years ago by Gunther Schadow

Description: modified (diff) new → reject_proposed

### comment:8 Changed 13 months ago by Simon Cox

Component: → help reject_proposed → new

### comment:9 Changed 13 months ago by Simon Cox

Resolution: → wontfix new → closed
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