chemistry: Chemical Elements and Oxides

In nexus: Sourcing Archaeological Materials by Chemical Composition

Chemical Elements and Oxides

Description

Identify oxides and major, minor and traces elements in a compositional data matrix.

Usage

is_element_major(object, ...)

is_element_minor(object, ...)

is_element_trace(object, ...)

is_oxide(object, ...)

## S4 method for signature 'character'
is_oxide(object)

## S4 method for signature 'CompositionMatrix'
is_oxide(object)

## S4 method for signature 'CompositionMatrix'
is_element_major(object, min = 1/100, max = Inf)

## S4 method for signature 'CompositionMatrix'
is_element_minor(object, min = 0.1/100, max = 1/100)

## S4 method for signature 'CompositionMatrix'
is_element_trace(object, min = -Inf, max = 0.1/100)

Arguments

object	A CompositionMatrix object.
...	Currently not used.
min	A length-one numeric vector specifying the lower bound for element identification.
max	A length-one numeric vector specifying the upper bound for element identification.

Details

There is no definite classification of what are the major, minor and trace elements are. By default, the following rule of thumb is used:

major elements

The major elements are those that define the material under study. Major elements usually have concentrations of above 1%.

minor elements

Minor elements usually have concentrations between 1% and 0.1%

trace elements

Trace elements usually have concentrations of less than 0.1%.

Value

A logical vector.

Note

is_oxide() uses a regular expression (it does not check if elements exist or if stoichiometry is valid).

Author(s)

N. Frerebeau

Examples

## Data from Day et al. 2011
data("kommos", package = "folio") # Coerce to compositional data
kommos <- remove_NA(kommos, margin = 1) # Remove cases with missing values
coda <- as_composition(kommos, groups = 1) # Use ceramic types for grouping

is_element_major(coda)
is_element_minor(coda)
is_element_trace(coda)

is_oxide(coda)

nexus documentation built on Sept. 11, 2024, 6:43 p.m.