Opened 12 years ago

Closed 3 months ago

## #24 closed enhancement (wontfix)

# Particle Mesh Size units

Reported by: | Bruce Simons | Owned by: | |
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Priority: | major | Milestone: | |

Component: | help | Keywords: | sieve mesh "particle size" |

Cc: |

### Description (last modified by )

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?

### Attachments (2)

### Change History (11)

### comment:1 follow-up: 2 Changed 12 years ago by

### comment:2 Changed 12 years ago by

Replying to gschadow:

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 12 years ago by

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

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 11 years ago by

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

### comment:5 Changed 11 years ago by

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 8 years ago by

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

### comment:7 Changed 7 years ago by

Description: | modified (diff) |
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Status: | new → reject_proposed |

### comment:8 Changed 3 months ago by

Component: | → help |
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Status: | reject_proposed → new |

### comment:9 Changed 3 months ago by

Resolution: | → wontfix |
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Status: | new → closed |

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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.