Change in modeling nm:ElectricalConductivity

[mdeagen]

Electrical conductivity is measured under DC or AC field conditions. If DC, only a voltage is provided. If AC, voltage (peak or RMS) is provided along with frequency.

Previously, the sio:Attribute nm:ElectricalConductivity stored what appeared to be DC conductivity values. A plot based on this search result looked like this.

Now, nm:ElectricalConductivity seems to return AC conductivity values. This is what the plot now looks like this (only 1000 of 9000+ rows included here due to filesize limitations)

Note: An earlier version of the ontology spelled the term as nm:ElectricConductivity. The term appears to have been corrected to nm:ElectricalConductivity. However, the Ontology Spreadsheet still has a reference to nm:ElectricConductivity.

The main questions are:

• How is DC conductivity modeled in the KG?
• How is AC conductivity modeled in the KG?
• What SPARQL query will return DC Conductivity in order to replicate earlier plots?

Below is the SPARQL query that previously would have returned DC conductivity values, but now returns AC conductivity values:

PREFIX nm: <http://nanomine.org/ns/>
PREFIX sio: <http://semanticscience.org/resource/>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX dct: <http://purl.org/dc/terms/>

SELECT DISTINCT * WHERE {
  ?sample a nm:PolymerNanocomposite ;
          sio:hasAttribute [ a nm:ElectricalConductivity ;
                             sio:hasValue ?Conductivity ;
                             sio:hasUnit [ rdfs:label ?unit ] 
                           ] .
  ?control sio:hasRole [ a sio:ControlRole ;
                         sio:inRelationTo ?sample ] ;
           sio:hasAttribute [ a nm:ElectricalConductivity ;
                             sio:hasValue ?controlConductivity ;
                             sio:hasUnit [ rdfs:label ?unit ] 
                            ] .
  ?sample a nm:PolymerNanocomposite ;
          sio:hasComponentPart [ a [ rdfs:label ?Filler ]; 
                                 sio:hasRole [ a nm:Filler ] ;
                                 sio:hasAttribute [ a nm:MassFraction ;
                                                    sio:hasValue ?Loading_mass ]
                               ] ,
                               [ a [ rdfs:label ?Matrix ];
                                 sio:hasRole [ a nm:Matrix] ] .
} 

[mdeagen]

Correction: Legacy DC conductivity data are still stored as nm:ElectricConductivity.

The following SPARQL query achieves expected results:

PREFIX nm: <http://nanomine.org/ns/>
PREFIX sio: <http://semanticscience.org/resource/>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX dct: <http://purl.org/dc/terms/>

SELECT DISTINCT * WHERE {
  ?sample a nm:PolymerNanocomposite ;
          sio:hasAttribute [ a nm:ElectricConductivity ;
                             sio:hasValue ?Conductivity ;
                             sio:hasUnit [ rdfs:label ?unit ] 
                           ] .
  ?control sio:hasRole [ a sio:ControlRole ;
                         sio:inRelationTo ?sample ] ;
           sio:hasAttribute [ a nm:ElectricConductivity ;
                             sio:hasValue ?controlConductivity ;
                             sio:hasUnit [ rdfs:label ?unit ] 
                            ] .
  ?sample a nm:PolymerNanocomposite ;
          sio:hasComponentPart [ a [ rdfs:label ?Filler ]; 
                                 sio:hasRole [ a nm:Filler ] ;
                                 sio:hasAttribute [ a nm:MassFraction ;
                                                    sio:hasValue ?Loading_mass ]
                               ] ,
                               [ a [ rdfs:label ?Matrix ];
                                 sio:hasRole [ a nm:Matrix] ] .
} 

The nm:ElectricConductivity and nm:ElectricalConductivity representations still should be unified, in addition to specifying AC or DC measurement conditions.