Copper alloy classification according to Pollard et al. (2015).

Classification of copper alloy artefacts following the system proposed in Pollard et al. (2015) based Sn, Zn, and Pb concentrations in wt%.

Usage

copper_alloy_pollard(
  df,
  elements = c(Sn = "Sn", Zn = "Zn", Pb = "Pb"),
  id_column = "ID",
  group_as_symbol = FALSE,
  ...
)

Arguments

df

data frame with the data to be classified.

elements

named character vector with column names of Sn, Zn, and Pb.

id_column

name of the column in df with the identifiers of each row. Default to ID.

group_as_symbol

logical. If FALSE, the default, copper groups are reported as their label. Otherwise, copper groups are reported by their symbol.

...

Additional arguments for unit conversion, see atomic_conversion and oxide_conversion for details.

Value

If df is an ASTR object, the output is an object of the same type including the ID column, the contextual columns, the elements used for classification and the alloy type. In all other cases, the data frame provided as input with the column for the alloy type.

References

Pollard, A. M., Bray, P., Gosden, C., Wilson, A., and Hamerow, H. (2015). Characterising copper-based metals in Britain in the first millennium AD: a preliminary quantification of metal flow and recycling. Antiquity 89(345), pp. 697-713. https://doi.org/10.15184/aqy.2015.20

See also

Other copper alloy classifications: copper_alloy_bb(), copper_group_bray()

Examples

sample_df <- data.frame(
  ID = 1:8,
  Sn = c(0.5, 0.5, 5, 5, 0.5, 5, 5, 5),
  Zn = c(0.5, 0.5, 0.5, 0.5, 5, 5, 0.5, 5),
  Pb = c(0.5, 5, 0.5, 5, 0.5, 0.5, 5, 5)
)
copper_alloy_pollard(sample_df)
#>   ID  Sn  Zn  Pb copper_alloy_pollard
#> 1  1 0.5 0.5 0.5               Copper
#> 2  2 0.5 0.5 5.0        Leaded copper
#> 3  3 5.0 0.5 0.5               Bronze
#> 4  4 5.0 0.5 5.0        Leaded bronze
#> 5  5 0.5 5.0 0.5                Brass
#> 6  6 5.0 5.0 0.5             Gunmetal
#> 7  7 5.0 0.5 5.0        Leaded bronze
#> 8  8 5.0 5.0 5.0      Leaded gunmetal

# For ASTR objects, units and oxides are automatically converted
sample_df <- as_ASTR(
  data.frame(
    ID = 1:8,
    SnO_wtP = c(0.5, 0.5, 5, 5, 0.5, 5, 5, 5),
    ZnO_wtP = c(0.5, 0.5, 0.5, 0.5, 5, 5, 0.5, 5),
    PbO_wtP = c(0.5, 5, 0.5, 5, 0.5, 0.5, 5, 5)
  )
)
copper_alloy_pollard(sample_df, elements = c(Sn = "SnO", Zn = "ZnO", Pb = "PbO"))
#> ASTR table
#> Analytical columns: Sn, Zn, Pb
#> Contextual columns: copper_alloy_pollard 
#> # A data frame: 8 × 5
#>      ID    Sn    Zn    Pb copper_alloy_pollard
#>   <int> [wtP] [wtP] [wtP] <chr>               
#> 1     1 0.441 0.402 0.464 Copper              
#> 2     2 0.441 0.402 4.64  Leaded copper       
#> 3     3 4.41  0.402 0.464 Bronze              
#> 4     4 4.41  0.402 4.64  Leaded bronze       
#> 5     5 0.441 4.02  0.464 Brass               
#> 6     6 4.41  4.02  0.464 Gunmetal            
#> 7     7 4.41  0.402 4.64  Leaded bronze       
#> 8     8 4.41  4.02  4.64  Leaded gunmetal