PLDO focuses on the description of planar defects in crystalline materials.
Abril Azocar Guzman and Stefan Sandfeld. (2025). Planar Defect Ontology.
definition
The official definition, explaining the meaning of a class or property. Shall be Aristotelian, formalized and normalized. Can be augmented with colloquial definitions.
2012-04-05: Barry Smith The official OBI definition, explaining the meaning of a class or property: 'Shall be Aristotelian, formalized and normalized. Can be augmented with colloquial definitions' is terrible. Can you fix to something like: A statement of necessary and sufficient conditions explaining the meaning of an expression referring to a class or property. Alan Ruttenberg Your proposed definition is a reasonable candidate, except that it is very common that necessary and sufficient conditions are not given. Mostly they are necessary, occasionally they are necessary and sufficient or just sufficient. Often they use terms that are not themselves defined and so they effectively can't be evaluated by those criteria. On the specifics of the proposed definition: We don't have definitions of 'meaning' or 'expression' or 'property'. For 'reference' in the intended sense I think we use the term 'denotation'. For 'expression', I think we you mean symbol, or identifier. For 'meaning' it differs for class and property. For class we want documentation that let's the intended reader determine whether an entity is instance of the class, or not. For property we want documentation that let's the intended reader determine, given a pair of potential relata, whether the assertion that the relation holds is true. The 'intended reader' part suggests that we also specify who, we expect, would be able to understand the definition, and also generalizes over human and computer reader to include textual and logical definition. Personally, I am more comfortable weakening definition to documentation, with instructions as to what is desirable. We also have the outstanding issue of how to aim different definitions to different audiences. A clinical audience reading chebi wants a different sort of definition documentation/definition from a chemistry trained audience, and similarly there is a need for a definition that is adequate for an ontologist to work with.
PERSON:Daniel Schober
definition source
Formal citation, e.g. identifier in external database to indicate / attribute source(s) for the definition. Free text indicate / attribute source(s) for the definition. EXAMPLE: Author Name, URI, MeSH Term C04, PUBMED ID, Wiki uri on 31.01.2007
Discussion on obo-discuss mailing-list, see http://bit.ly/hgm99w
Examples of a Contributor include a person, an organization, or a service. Typically, the name of a Contributor should be used to indicate the entity.
Contributor
An entity responsible for making contributions to the resource.
Examples of a Creator include a person, an organization, or a service. Typically, the name of a Creator should be used to indicate the entity.
Creator
An entity primarily responsible for making the resource.
Description may include but is not limited to: an abstract, a table of contents, a graphical representation, or a free-text account of the resource.
Description
An account of the resource.
Title
A name given to the resource.
In current practice, this term is used primarily with literal values; however, there are important uses with non-literal values as well. As of December 2007, the DCMI Usage Board is leaving this range unspecified pending an investigation of options.
The range of skos:altLabel is the class of RDF plain literals.
skos:prefLabel, skos:altLabel and skos:hiddenLabel are pairwise disjoint properties.
alternative label
An alternative lexical label for a resource.
Acronyms, abbreviations, spelling variants, and irregular plural/singular forms may be included among the alternative labels for a concept. Mis-spelled terms are normally included as hidden labels (see skos:hiddenLabel).
example
An example of the use of a concept.
A general note, for any purpose.
A resource has no more than one value of skos:prefLabel per language tag, and no more than one value of skos:prefLabel without language tag.
The range of skos:prefLabel is the class of RDF plain literals.
preferred label
The preferred lexical label for a resource, in a given language.
The relation between a grain boundary and the corresponding energy.
The relation between a surface structure and the corresponding energy.
The relation between a mixed grain boundary and the tilt grain boundary component.
The relation between a mixed grain boundary and the twist grain boundary component.
The geometrical degrees of freedom are the parameters that are necessary to characterize a grain boundary.
A data property indicating the grain boundary (GB) plane using Miller indices.
A data property indicating the misorientation angle (θ) of the grains with respect to each other.
A disorientation angle can also be used to describe the grain boundary and is defined by the minimum misorientation angle when the misorientation axis is found in the standard stereographic triangle.
A data property indicating the rotation axis [uvw].
A data property linking a GB with its sigma value.
Sigma value of a GB is the coincidence index, calculated as the ratio of the coincidence unit cell volume by the crystal primitive unit cell volume. The coincidence index refers to the Coincidence Site Lattice (CSL).
There are five macroscopic degrees of freedom (DOFs) that are sufficient to describe the thermodynamic description of the grain boundary.
In simulations of grain boundaries, the macroscopic DOFs are imposed on the structure.
The microscopic degrees of freedom (DOFs) refer to the translation of one crystal with respect to the other at the microscopic scale. The microscopic parameters result from the relaxation process and are not independent of the macroscopic parameters.
In simulations of grain boundaries, the microscopic DOFs are obtained after the grain boundary energy minimization.
An antiphase boundary is a planar defect that occurs in ordered alloys. The boundary separates two domains of the same ordered phase.
A calculated property is a property of a material resulting from a calculation or simulation.
A computational sample is a representative system of a material for analysis through computational methods in the context of materials science.
Energy is a physical quantity characterizing the ability of a system to do work.
The gamma-surface is the excess interlayer energy, γ, as a function of an imposed rigid-body translation, t, parallel to the interface.
A grain boundary is a planar defect that separates two crystals (or grains) of the same material.
Grain boundary energy is the excess energy due to the presence of a grain boundary, with the perfect lattice (bulk) as the reference.
Usually expressed in units of energy per area.
A low angle grain boundary is a grain boundary with a misorientation angle lower than 15 degrees.
A mixed grain boundary is a grain boundary where the [uvw] rotation axis has perpendicular and parallel components with respect to the boundary plane.
A planar defect is a defect of the crystal structure across a plane. It is considered to be a two-dimensional defect, such as an internal interface or the surface.
A stacking fault is a planar defect created by an error (fault) in the order of the sequential layering of crystallographic planes.
The free surface (or external surface) of the material is a planar defect where the surface atoms have no neighbors or cohesive bonds on the external side.
Surface energy is the excess energy per unit area at a material's surface due to broken atomic bonds, measured relative to the bulk.
A symmetrical tilt grain boundary is a tilt grain boundary where the two grains are symmetric. The boundary plane has the same Miller indices in crystals I and II: {hkl}_1 = {hkl}_2.
A tilt boundary is a grain boundary with a [uvw] rotation axis perpendicular to the boundary plane.
A twin boundary is a planar defect that occurs between two separate crystals which are mirror images of each other. Both crystals have the same crystal structure.
A twist boundary is a grain boundary with a [uvw] rotation axis contained within the boundary plane.
Work of separation is the energy required per unit area to separate a material into two free surfaces, overcoming atomic or intermolecular bonds at the interface.
A meaningful collection of concepts.
An idea or notion; a unit of thought.
A set of concepts, optionally including statements about semantic relationships between those concepts.
Thesauri, classification schemes, subject heading lists, taxonomies, 'folksonomies', and other types of controlled vocabulary are all examples of concept schemes. Concept schemes are also embedded in glossaries and terminologies.
An ordered collection of concepts, where both the grouping and the ordering are meaningful.
skos:broadMatch is used to state a hierarchical mapping link between two conceptual resources in different concept schemes.
Relates a concept to a concept that is more general in meaning.
skos:broaderTransitive is a transitive superproperty of skos:broader.
A note about a modification to a concept.
skos:closeMatch is used to link two concepts that are sufficiently similar that they can be used interchangeably in some information retrieval applications. In order to avoid the possibility of "compound errors" when combining mappings across more than two concept schemes, skos:closeMatch is not declared to be a transitive property.
A note for an editor, translator or maintainer of the vocabulary.
skos:exactMatch is used to link two concepts, indicating a high degree of confidence that the concepts can be used interchangeably across a wide range of information retrieval applications. skos:exactMatch is a transitive property, and is a sub-property of skos:closeMatch.
Relates, by convention, a concept scheme to a concept which is topmost in the broader/narrower concept hierarchies for that scheme, providing an entry point to these hierarchies.
A lexical label for a resource that should be hidden when generating visual displays of the resource, but should still be accessible to free text search operations.
A note about the past state/use/meaning of a concept.
Relates a resource (for example a concept) to a concept scheme in which it is included.
Relates two concepts coming, by convention, from different schemes, and that have comparable meanings
Relates a collection to one of its members.
Relates an ordered collection to the RDF list containing its members.
skos:narrowMatch is used to state a hierarchical mapping link between two conceptual resources in different concept schemes.
Relates a concept to a concept that is more specific in meaning.
skos:narrowerTransitive is a transitive superproperty of skos:narrower.
A notation, also known as classification code, is a string of characters such as "T58.5" or "303.4833" used to uniquely identify a concept within the scope of a given concept scheme.
Relates a concept to a concept with which there is an associative semantic relationship.
skos:relatedMatch is used to state an associative mapping link between two conceptual resources in different concept schemes.
A note that helps to clarify the meaning and/or the use of a concept.
Links a concept to a concept related by meaning.
Relates a concept to the concept scheme that it is a top level concept of.