== Draft set of categories for materials ontology (3/22/2017)==


Portion of Solid Material
   Pure Substance
     element
     compound
   Mixture (decomposed via physical change)
     homogeneous mixture
     heterogeneous mixture

Material property (BFO quality)
     compare with QUDT quantity kind 
     color 
     hardness
     ultimate tensile strength (qudt:quantityKind qudt-quantity:Stress)
     dynamic viscosity (qudt:quantityKind qudt-quantity:DynamicViscosity)
     glass-transition temperature

Composition (what and how much)
     mass fraction of an alloy (BFO quality)
     volume fraction of carbon fibers for a composite (BFO quality)
     repeating unit for a polymer chain (composition and structure)

Form
     plate
     sheet 
     forged alloy
     laminated composite
     woven composite

Structure
     alloy grain size (BFO quality)
     linear, branched, cross-linked, and networked polymer chain
     grain orientation

State
     stress state:  uni-axial, bi-axial, multi-axial, complex
     damage state:  crack, corrosion, burn
     thermal state

Environment
     chemical 
     mechanical load 
     thermal load
     radiation

Scale
     micro
     meso
     macro