{ "model": { "rank": 6422, "code": "thing-q108193", "model_id": "vr.tr.electrical-resistivity", "name": "electrical resistivity", "purpose": "Enable an agent to identify electrical resistivity, assess whether a reported value applies to a material and operating condition, and decide whether it can support comparison, calculation or material selection.", "family": "Thing Registry", "category": "Cross-cutting context", "status": "research-draft", "kind": "thing", "plane": "XCT", "domain": "XCT.QLT", "industry": "", "version": "", "url": "/models/thing/q108193/", "tier": 2, "score": 60, "payload": { "layer": "wikidata", "aliases": [ "residual resistivity" ], "aliasCount": 1, "merged": 1, "knownIn": 60, "facets": null, "markers": [], "lexicalClass": "", "senseRank": null, "alsoRegisteredAs": null, "source": { "dataset": "wikidata", "item": "Q108193", "url": "https://www.wikidata.org/wiki/Q108193", "license": "CC0 1.0" } }, "research": { "vercy": "1.0-draft", "publication": { "status": "research-draft", "adjudicationStatus": "unreviewed", "publishableCanonical": false, "generatedAt": "2026-09-07T14:28:12Z", "providers": [ "Codex", "Grok" ], "missingProviders": [], "pass": 2, "cost": { "grok": { "usd": 0.01232806, "turns": 1, "seconds": 135.6, "error": null }, "codex": { "seconds": 68.8, "error": "Reading additional input from stdin...\nOpenAI Codex v0.153.3\n--------\nworkdir: R:\\02_PROJECTS\\02_Meta_Models_Platforms\\Ver.cy\\current\\thing-registry-backlog\nmodel: gpt-6-astra\nprovider: openai\napproval: never\nsandbox: read-only\nreasoning effort: none\nreasoning summaries: none\nsession id: 01a07c40-1770-7bb2-a7f0-7797ed6a229d\n--------\nuser\nYou are drafting a Vercy meta-model for one registered thing. Answer as JSON only, no prose around it.\n\nThing: electrical resistivity\nRegistry id: vr.tr.electrical-resistivity\nPlane / domain: XCT / XCT.QLT\nRegistry definition: (none recorded)\nNames folded into" } } }, "metaModel": { "id": "THING-Q108193", "registryId": "vr.tr.electrical-resistivity", "name": "electrical resistivity", "version": "0.1.0-research.1", "entryKind": "thing", "family": "Thing Registry", "domain": [ "XCT.QLT" ], "status": "research-draft" }, "canonicalUrl": "https://ver.cy/models/thing/q108193/", "model": { "registry_id": "vr.tr.electrical-resistivity", "name": "electrical resistivity", "purpose": "Enable an agent to identify electrical resistivity, assess whether a reported value applies to a material and operating condition, and decide whether it can support comparison, calculation or material selection.", "definition": "Electrical resistivity is the intensive constitutive property of a material that relates electric field strength to current density (ρ = E/J in isotropic linear media), equivalently the DC resistance of a uniform prism multiplied by cross-sectional area and divided by length, with SI unit ohm-metre.", "scope_statement": "This model owns electrical resistivity as a material response relating electric field to current density under specified conditions, including its directional character, measurement interpretation and limits of applicability.", "in_scope": [ "Bulk electrical resistivity attributed to an identified material and material state", "Scalar or tensor representation and the directions to which values apply", "Dependence on temperature, composition, microstructure and electrical excitation", "Measurement-derived values, uncertainty and separation of specimen geometry from material response", "Conditions under which resistivity supports comparisons or resistance calculations" ], "out_of_scope": [ "Resistance of a complete component, circuit or installation", "Contact resistance and interface-specific resistivity as independently modelled quantities", "Sheet resistance as a distinct thin-film quantity", "Dielectric permittivity, polarization and breakdown strength", "Thermal resistivity and resistance to heat flow", "Complete impedance spectra and equivalent-circuit models" ], "distinguishing_features": [ "A bulk resistivity value has units of ohm metre; a value in ohms describes resistance and requires geometry before it can establish resistivity.", "For a homogeneous specimen with uniform current flow, resistance changes with length and cross-sectional area while the inferred resistivity should remain consistent at the same material state.", "A sheet resistance in ohms per square requires a justified conducting thickness and suitable film assumptions before conversion to bulk resistivity.", "Electrical conductivity is the reciprocal of scalar resistivity in the applicable linear description; directional tensor descriptions require matrix inversion rather than elementwise reciprocals.", "A voltage drop dominated by electrodes or contacts cannot be assigned to bulk resistivity without separating those contributions." ], "characteristics": [ { "name": "Resistivity value", "kind": "measurement", "unit_or_values": "Ω·m, with uncertainty or a qualified upper or lower bound", "why_it_matters": "Quantifies the material response and distinguishes an estimate from a measurement limit." }, { "name": "Representation", "kind": "category", "unit_or_values": "Scalar; directional value; tensor; effective value", "why_it_matters": "Determines whether a single number adequately describes the intended current direction and material structure." }, { "name": "Material and specimen attribution", "kind": "relation", "unit_or_values": "Identified material, grade, batch, specimen and relevant preparation history", "why_it_matters": "Prevents values from being transferred between materially different compositions or structures." }, { "name": "Temperature", "kind": "measurement", "unit_or_values": "K or °C, with measurement location and stability where relevant", "why_it_matters": "Resistivity comparisons and predictions require a known thermal condition." }, { "name": "Electrical excitation", "kind": "measurement", "unit_or_values": "Current density in A/m² or electric field in V/m; frequency in Hz and waveform where applicable", "why_it_matters": "Exposes nonlinear response, frequency dependence and possible heating during measurement." }, { "name": "Direction and coordinate frame", "kind": "relation", "unit_or_values": "Current and field directions relative to specimen axes, crystal axes or processing orientation", "why_it_matters": "Makes directional and tensor values interpretable." }, { "name": "Material condition", "kind": "state", "unit_or_values": "Relevant phase, moisture condition, strain, porosity, defect state and aging condition", "why_it_matters": "Identifies changes that may invalidate an otherwise correctly attributed value." }, { "name": "Measurement basis", "kind": "category", "unit_or_values": "Direct specimen measurement; geometry-based inference; fitted estimate; literature value; calculated prediction", "why_it_matters": "Determines what evidence and assumptions must accompany the value." }, { "name": "Applicable regime", "kind": "state", "unit_or_values": "Established temperature, excitation, frequency, direction and material-state limits", "why_it_matters": "Constrains reuse of the value outside the conditions that support it." } ], "affordances": [ "Normalize reported resistivity units while retaining the original value and conditions.", "Compare materials only after checking temperature, direction, material condition and measurement basis.", "Infer resistivity from resistance and specimen geometry when the current-flow assumptions are justified.", "Estimate specimen resistance from applicable resistivity and geometry.", "Identify whether a discrepant value calls for contact checks, thermal stabilization, directional measurement or new material characterization.", "Accept, qualify or reject a resistivity value for a stated design or analysis task." ] }, "sources": [ { "id": "iec-60050-121", "title": "IEC 60050-121 International Electrotechnical Vocabulary - Electromagnetism (resistivity, IEV 121-12-04)", "url": "https://www.electropedia.org/", "what_it_supports": "Specialist definition, quantity name, symbol ρ and SI unit ohm-metre in the electrotechnical vocabulary.", "url_status": "live" }, { "id": "bipm-si-brochure", "title": "The International System of Units (SI Brochure)", "url": "https://www.bipm.org/en/publications/si-brochure", "what_it_supports": "Coherent derived unit ohm-metre for resistivity and the relation of the ohm to the SI.", "url_status": "live" }, { "id": "astm-d257", "title": "ASTM D257 Standard Test Methods for DC Resistance or Conductance of Insulating Materials", "url": "", "what_it_supports": "Laboratory distinction between volume and surface resistivity, electrode geometry and typical insulating ranges." }, { "id": "ieee-std-81", "title": "IEEE Std 81 Guide for Measuring Earth Resistivity, Ground Impedance, and Earth Surface Potentials of a Grounding System", "url": "", "what_it_supports": "Field practice for soil/earth resistivity, Wenner and related arrays, and use in grounding design." }, { "id": "astm-g57", "title": "ASTM G57 Standard Test Method for Field Measurement of Soil Resistivity Using the Wenner Four-Electrode Method", "url": "", "what_it_supports": "Soil-resistivity measurement as used in corrosion and buried-structure practice, including customary ohm-centimetre reporting." }, { "id": "iec-62631-3-1", "title": "IEC 62631-3-1 Dielectric and resistive properties of solid insulating materials - Determination of resistive properties (DC methods) - Volume resistance and volume resistivity", "url": "", "what_it_supports": "Current IEC method replacing older IEC 60093 for volume resistivity of solid insulation." }, { "id": "wikipedia-resistivity", "title": "Electrical resistivity and conductivity", "url": "https://en.wikipedia.org/wiki/Electrical_resistivity_and_conductivity", "what_it_supports": "Order-of-magnitude ranges by material class, relation to conductivity, IACS copper reference and common confusions with resistance.", "url_status": "live" } ], "structure": { "bundles": [ { "id": "quantity-identity", "name": "Quantity identity", "description": "Establishes which electrical material response the reported quantity represents.", "rationale": "Resistivity is readily confused with resistance, sheet resistance and contact effects, which support different decisions.", "layers": [ { "id": "bulk-quantity-boundary", "name": "Bulk quantity boundary", "description": "Separates material resistivity from specimen and interface quantities.", "findings": [ { "id": "reported-quantity-identification", "name": "Reported quantity identification", "description": "Record the quantity actually reported and the evidence for interpreting it as bulk electrical resistivity.", "questions": [ { "text": "Does the source report bulk resistivity, resistance, sheet resistance or an interface-specific quantity?", "kind": "definition", "id": "reported-quantity-identification-q01" }, { "text": "Do the units and measurement description support the claimed quantity without an unstated thickness or geometry conversion?", "kind": "boundary", "id": "reported-quantity-identification-q02" } ] } ] }, { "id": "constitutive-representation", "name": "Constitutive representation", "description": "Determines how electric field and current density are related in the intended description.", "findings": [ { "id": "scalar-directional-or-tensor", "name": "Scalar, directional or tensor response", "description": "Record whether resistivity is a scalar, a directional observation or a tensor, with its defining convention.", "questions": [ { "text": "Is a scalar relation between electric field and current density justified, or must directional coupling be retained?", "kind": "definition", "id": "scalar-directional-or-tensor-q01" }, { "text": "Which coordinate frame and field or current directions define the reported components?", "kind": "measurement", "id": "scalar-directional-or-tensor-q02" }, { "text": "If the response is nonlinear or frequency dependent, what precise apparent, differential or complex quantity is being called resistivity?", "kind": "boundary", "id": "scalar-directional-or-tensor-q03" } ] } ] } ] }, { "id": "material-and-condition", "name": "Material and condition", "description": "Anchors resistivity to the material identity and physical conditions that make it applicable.", "rationale": "A resistivity value cannot be safely treated as a universal constant of a material name.", "layers": [ { "id": "material-attribution", "name": "Material attribution", "description": "Identifies the material and structure represented by the value.", "findings": [ { "id": "composition-and-structure", "name": "Composition and structure", "description": "Record composition, processing and structural details relevant to electrical transport.", "questions": [ { "text": "Which material grade, composition, dopant condition or batch does the value describe?", "kind": "provenance", "id": "composition-and-structure-q01" }, { "text": "Which features such as crystallographic texture, porosity, phase mixture or processing direction must match before this value can be transferred?", "kind": "boundary", "id": "composition-and-structure-q02" } ] } ] }, { "id": "operating-condition", "name": "Operating condition", "description": "Records thermal, environmental and excitation conditions during characterization and use.", "findings": [ { "id": "condition-dependent-value", "name": "Condition-dependent value", "description": "Associate each value with the conditions under which it was established.", "questions": [ { "text": "At what specimen temperature, electrical excitation and frequency was the value established?", "kind": "measurement", "id": "condition-dependent-value-q01" }, { "text": "Were moisture, pressure, strain, illumination or magnetic field controlled where they could affect this material?", "kind": "measurement", "id": "condition-dependent-value-q02" }, { "text": "Which differences between characterization conditions and intended use require a correction or a new measurement?", "kind": "action", "id": "condition-dependent-value-q03" } ] } ] } ] }, { "id": "measurement-and-inference", "name": "Measurement and inference", "description": "Establishes how observations support the resistivity value and its uncertainty.", "rationale": "Geometry, current distribution and unwanted voltage or current paths can make an apparent resistivity unrepresentative of the bulk material.", "layers": [ { "id": "specimen-to-property", "name": "Specimen to property", "description": "Captures the measurement arrangement and conversion from electrical observations to material response.", "findings": [ { "id": "method-and-geometric-assumptions", "name": "Method and geometric assumptions", "description": "Record the method, specimen dimensions and current-flow assumptions used to derive resistivity.", "questions": [ { "text": "Which method and electrode arrangement produced the current and voltage observations?", "kind": "provenance", "id": "method-and-geometric-assumptions-q01" }, { "text": "Which dimensions, thicknesses or geometry correction factors enter the resistivity calculation?", "kind": "measurement", "id": "method-and-geometric-assumptions-q02" }, { "text": "What supports the assumed current distribution, homogeneity and directional interpretation for this specimen?", "kind": "boundary", "id": "method-and-geometric-assumptions-q03" } ] } ] }, { "id": "measurement-limitations", "name": "Measurement limitations", "description": "Identifies unwanted contributions and the limits of the resulting estimate.", "findings": [ { "id": "bulk-signal-and-uncertainty", "name": "Bulk signal and uncertainty", "description": "Record how the bulk response was distinguished from contacts, leakage, offsets and instrument limits.", "questions": [ { "text": "How were contact voltage drops, leakage paths, thermoelectric offsets and specimen self-heating assessed or controlled?", "kind": "measurement", "id": "bulk-signal-and-uncertainty-q01" }, { "text": "What uncertainty follows from the electrical readings, dimensions, temperature and method corrections?", "kind": "measurement", "id": "bulk-signal-and-uncertainty-q02" }, { "text": "Does the evidence support a numerical value, a detection-limited bound or a requirement to repeat the measurement?", "kind": "action", "id": "bulk-signal-and-uncertainty-q03" } ] } ] } ] }, { "id": "applicability-and-decisions", "name": "Applicability and decisions", "description": "Defines how resistivity evidence may support calculations, comparisons and follow-up actions.", "rationale": "An agent must know when a recorded value remains usable and when extrapolation or conversion would exceed its evidence.", "layers": [ { "id": "comparison-and-conversion", "name": "Comparison and conversion", "description": "Constrains normalization, conductivity conversion and geometry-based calculations.", "findings": [ { "id": "permitted-derived-uses", "name": "Permitted derived uses", "description": "Identify which comparisons and derived quantities are justified by the recorded representation and conditions.", "questions": [ { "text": "Are the material conditions, temperatures, directions and excitation regimes sufficiently aligned for the proposed comparison?", "kind": "boundary", "id": "permitted-derived-uses-q01" }, { "text": "Does a proposed conductivity conversion require a scalar reciprocal or inversion of a complete resistivity tensor?", "kind": "action", "id": "permitted-derived-uses-q02" }, { "text": "Does the intended resistance calculation justify a uniform geometric relation, or require a spatial current-flow model?", "kind": "action", "id": "permitted-derived-uses-q03" } ] } ] }, { "id": "validity-and-recharacterization", "name": "Validity and recharacterization", "description": "Defines the evidence limits and changes that trigger review.", "findings": [ { "id": "use-envelope-and-review-triggers", "name": "Use envelope and review triggers", "description": "Record supported operating ranges, decision criteria and reasons to obtain new evidence.", "questions": [ { "text": "Over what temperature, excitation, frequency and material-state range is the value or fitted relationship supported?", "kind": "boundary", "id": "use-envelope-and-review-triggers-q01" }, { "text": "What application-specific criterion determines whether the value and its uncertainty are adequate for the intended decision?", "kind": "action", "id": "use-envelope-and-review-triggers-q02" }, { "text": "Which changes in processing, aging, moisture, phase or measured response require recharacterization?", "kind": "action", "id": "use-envelope-and-review-triggers-q03" } ] } ] } ] }, { "id": "evidence-and-external-alignment", "name": "Evidence and external alignment", "description": "What the world already says about this thing, gathered so the model can be checked against it.", "rationale": "A model that cannot be lined up against existing standards, identifiers and practice cannot be adopted by anyone who already uses them.", "layers": [ { "id": "reported-evidence", "name": "Reported evidence", "description": "Findings from the breadth pass, kept separate from the structural claims.", "findings": [ { "id": "evidence-kinds", "name": "Kinds and varieties", "description": "Reported by the breadth pass; each item needs checking against its source before it becomes normative.", "evidence": [ "Volume (bulk) DC resistivity of a homogeneous solid or liquid", "Surface resistivity of a planar solid (current constrained to a surface layer)", "AC and complex resistivity, including frequency-dependent and imaginary parts in dielectrics and dispersive earth", "Apparent resistivity as inverted from a geoelectrical electrode array", "Residual resistivity of a metal after phonon scattering is frozen out at low temperature", "Anisotropic (tensor) resistivity in crystals, composites, rolled metals and stratified ground", "Ionic or electrolytic resistivity of electrolytes, moist soils and mixed conductors", "Effective earth or soil resistivity as a field-scale equivalent used in earthing design" ], "questions": [ { "id": "evidence-kinds-q01", "text": "Which of these kinds and varieties hold for the sense of electrical resistivity this model covers, and on what evidence?", "kind": "provenance" } ] }, { "id": "evidence-identifiers", "name": "Identifiers and schemes", "description": "Reported by the breadth pass; each item needs checking against its source before it becomes normative.", "evidence": [ { "scheme": "Wikidata", "value_or_pattern": "Q179918", "note": "Item for electrical resistivity as a physical quantity." }, { "scheme": "IEC Electropedia / IEV", "value_or_pattern": "121-12-04", "note": "Quantity 'resistivity' in IEC 60050-121; conductivity is the neighbouring IEV entry." }, { "scheme": "ISO 80000-6", "value_or_pattern": "quantity name resistivity, symbol ρ, unit Ω·m", "note": "Quantities and units - Electromagnetism; item number varies by edition, so the quantity name is the stable handle." }, { "scheme": "SI derived unit", "value_or_pattern": "Ω·m (ohm-metre)", "note": "Coherent SI unit; still often written ohm-cm or µΩ·cm in metals and soils practice." }, { "scheme": "IACS", "value_or_pattern": "100% IACS ≡ 1.7241×10⁻⁸ Ω·m at 20 °C", "note": "International Annealed Copper Standard; conductor materials are often named by % IACS rather than SI resistivity." } ], "questions": [ { "id": "evidence-identifiers-q01", "text": "Which of these identifiers and schemes hold for the sense of electrical resistivity this model covers, and on what evidence?", "kind": "provenance" } ] }, { "id": "evidence-standards-and-regulation", "name": "Standards and regulation", "description": "Reported by the breadth pass; each item needs checking against its source before it becomes normative.", "evidence": [ "IEC 62631-3-1 (and legacy IEC 60093) - volume resistivity of solid insulating materials (IEC)", "IEC 62631-3-2 - surface resistance and surface resistivity of solid insulating materials (IEC)", "IEC 61340 series - electrostatics; classification of planar materials by surface resistivity for ESD control (IEC)", "ASTM D257 - DC resistance or conductance of insulating materials (ASTM International)", "ASTM B193 - resistivity of electrical conductor materials (ASTM International)", "ASTM G57 / ASTM G187 - field and laboratory soil resistivity for corrosion work (ASTM International)", "IEEE Std 81 - earth resistivity and grounding-system measurements (IEEE)", "ISO 1853 - resistivity of conducting and dissipative rubbers (ISO)", "ISO 3915 - conductivity/resistivity of plastics (ISO)" ], "questions": [ { "id": "evidence-standards-and-regulation-q01", "text": "Which of these standards and regulation hold for the sense of electrical resistivity this model covers, and on what evidence?", "kind": "provenance" } ] }, { "id": "evidence-real-world-use", "name": "Real-world use", "description": "Reported by the breadth pass; each item needs checking against its source before it becomes normative.", "evidence": [ "Specifying copper, aluminium and steel conductors and busbars (often as % IACS or µΩ·cm at 20 °C).", "Sizing and siting earth electrodes and substation grounding grids from measured soil resistivity profiles.", "Classifying ESD-protective packaging and flooring as conductive, dissipative or insulative by surface resistivity decades.", "In-line process control of semiconductor wafers and thin films with four-point probes (reported as resistivity or sheet resistance).", "DC and induced-polarisation geophysical surveys for minerals, groundwater and contamination, reported as apparent resistivity.", "Ranking soil corrosivity for buried pipe, tank and anode design.", "Condition assessment of cable and bushing insulation via volume resistivity or insulation resistance scaled to geometry.", "Water and ultrapure-water monitoring, usually as conductivity, which is the reciprocal of resistivity (MΩ·cm in UPW)." ], "questions": [ { "id": "evidence-real-world-use-q01", "text": "Which of these real-world use hold for the sense of electrical resistivity this model covers, and on what evidence?", "kind": "provenance" } ] }, { "id": "evidence-measurements", "name": "Typical measurements", "description": "Reported by the breadth pass; each item needs checking against its source before it becomes normative.", "evidence": [ { "quantity": "Volume resistivity of metallic conductors at 20 °C", "typical_range": "1.6×10⁻⁸ (silver/copper) to about 1×10⁻⁶ (cast irons, some alloys)", "unit": "Ω·m" }, { "quantity": "Volume resistivity of semiconductors", "typical_range": "roughly 10⁻⁵ (heavily doped) to 10⁴ (near-intrinsic Si/Ge class materials)", "unit": "Ω·m" }, { "quantity": "Volume resistivity of solid electrical insulation", "typical_range": "10⁸ to 10¹⁶ and higher when dry; collapses orders of magnitude with moisture", "unit": "Ω·m" }, { "quantity": "Surface resistivity (ESD and insulation practice)", "typical_range": "about 10³-10⁵ conductive, 10⁵-10¹² dissipative, >10¹² insulative (IEC 61340 decades)", "unit": "Ω (often styled Ω/sq)" }, { "quantity": "Effective soil / earth resistivity", "typical_range": "about 1 (wet clay, saline) to >10 000 (dry sand, crystalline rock); seawater ~0.2", "unit": "Ω·m" }, { "quantity": "Temperature coefficient of resistivity of pure metals near 20 °C", "typical_range": "about 0.003-0.006", "unit": "K⁻¹" }, { "quantity": "Residual resistivity ratio (RRR) of pure metals", "typical_range": "tens to >1000 for high-purity copper or aluminium", "unit": "dimensionless" } ], "questions": [ { "id": "evidence-measurements-q01", "text": "Which of these typical measurements hold for the sense of electrical resistivity this model covers, and on what evidence?", "kind": "provenance" } ] }, { "id": "evidence-failure-modes-and-hazards", "name": "Failure modes and hazards", "description": "Reported by the breadth pass; each item needs checking against its source before it becomes normative.", "evidence": [ "Metal resistivity rises with temperature, increasing I²R heating and, in overloaded conductors, thermal runaway and fire.", "Moisture, ionic contamination or tracking can drop insulation volume or surface resistivity by many decades and precipitate dielectric breakdown or shock.", "Two-terminal readings fold in contact and lead resistance, so a measured 'resistivity' can be far above the true bulk value.", "A single scalar ρ is unrepresentative for anisotropic, layered, porous or skin-effect-limited bodies; designs then under- or over-estimate current paths.", "Seasonal drying or freezing can raise soil resistivity and leave an earth electrode with much higher resistance than the design measurement.", "High-resistivity ground increases touch and step voltages around faults; low-resistivity saline ground accelerates corrosion of buried metal.", "In thin-film interconnects, high current density in a low-resistivity metal still drives electromigration open circuits." ], "questions": [ { "id": "evidence-failure-modes-and-hazards-q01", "text": "Which of these failure modes and hazards hold for the sense of electrical resistivity this model covers, and on what evidence?", "kind": "provenance" } ] }, { "id": "evidence-regional-variation", "name": "Regional variation", "description": "Reported by the breadth pass; each item needs checking against its source before it becomes normative.", "evidence": [ "SI and IEC work uses ohm-metre; US corrosion, soils and some wire tables still quote ohm-centimetre (factor of 100) or circular-mil-ohm per foot.", "Conductor trade practice names material by % IACS conductivity rather than SI resistivity, especially in North America.", "Surface resistivity is reported as ohms or as ohms per square depending on lab tradition; the numerical value is the same for a square specimen but the unit style differs.", "Earthing measurement practice follows IEEE Std 81 in much of North America and IEC/BS earthing guides (for example BS 7430) in the UK and many IEC markets.", "Ultrapure-water users speak in MΩ·cm resistivity; most other process industries speak in µS/cm conductivity of the same quantity.", "Geophysicists report apparent resistivity tied to a named array (Wenner, Schlumberger, dipole-dipole); materials labs report a geometry-corrected bulk ρ." ], "questions": [ { "id": "evidence-regional-variation-q01", "text": "Which of these regional variation hold for the sense of electrical resistivity this model covers, and on what evidence?", "kind": "provenance" } ] }, { "id": "evidence-neighbours", "name": "Neighbouring kinds and how to tell them apart", "description": "Reported by the breadth pass; each item needs checking against its source before it becomes normative.", "evidence": [ { "name": "Electrical conductivity", "difference": "Exact reciprocal for linear isotropic media (σ = 1/ρ); same specimen, inverted unit S/m versus Ω·m." }, { "name": "Electrical resistance", "difference": "Extensive circuit quantity R = ρℓ/A; two specimens of the same material can have different R but the same ρ." }, { "name": "Sheet resistance", "difference": "R□ = ρ/t for a uniform film; four-point-probe semiconductor data are often R□ in Ω/sq, not bulk ρ, until thickness is known." }, { "name": "Electrical impedance", "difference": "Includes reactance; |Z| equals resistance only in the DC or purely resistive limit, so AC 'resistivity' from |Z| is not DC ρ unless the phase is checked." }, { "name": "Surface resistance (as opposed to surface resistivity)", "difference": "Resistance between two defined electrodes on a surface; surface resistivity is that resistance scaled by electrode geometry (IEC 62631-3-2 / ASTM D257)." }, { "name": "Specific contact resistivity", "difference": "An interface figure of merit (Ω·m²), not a bulk material ρ; separated by transmission-line or Kelvin contact structures rather than a four-point bulk probe." }, { "name": "Thermal resistivity", "difference": "Fourier analogue (K·m/W) for heat flow; same word 'resistivity' in cable ratings, distinguished by the transported quantity (heat versus charge)." } ], "questions": [ { "id": "evidence-neighbours-q01", "text": "Which of these neighbouring kinds and how to tell them apart hold for the sense of electrical resistivity this model covers, and on what evidence?", "kind": "provenance" } ] } ] } ] } ] }, "openQuestions": [ "Does the registry intend this entry to include complex frequency-dependent resistivity, or should that interpretation be linked to a separate electrical-response model?", "Should nonlinear apparent resistivity and differential resistivity be owned here, and which conventions would distinguish them?", "Which authoritative methods and sources should govern geometry corrections, uncertainty and applicability for metals, semiconductors, insulators and heterogeneous materials?", "How should effective resistivity of composites, porous media and spatially varying materials be distinguished from constituent bulk resistivity?", "Which neighbouring registry entries already own conductivity, sheet resistance and contact resistivity, and what relationships should prevent duplicate coverage?" ], "statistics": { "bundles": 5, "layers": 9, "findings": 16, "questions": 30 } }, "draft": { "generator": "vr.draft.v3", "status": "draft-generated", "researched": false, "archetype": "abstract concept", "method": "Written from the archetype playbook - what this kind of thing needs beyond identity and provenance - and from the structure that recurred across 6,333 models already researched by two engines. Applied to this entry by rule. No source was read for this thing and no claim here is researched. This entry carries no facets of its own, so they were inferred from its domain - a guess about a whole domain applied to one thing.", "facetsInferred": true, "nextPass": "A researcher replaces this draft with a sourced specification. Treat every sentence below as a proposal to argue with.", "purpose": "Give an agent a durable, checkable way to recognise a electrical resistivity, record what state it is in, and decide what may be done with it.", "whatItIs": "Enable an agent to identify electrical resistivity, assess whether a reported value applies to a material and operating condition, and decide whether it can support comparison, calculation or material selection.", "characteristics": { "substance": "abstract", "origin": "conceptual", "agency": "inert" }, "whatYouCanDoWithIt": [ "observed and measured" ], "distinguishingFeatures": [ "Names folded into this entry, which a task may need to split apart again: residual resistivity.", "1 finer distinctions are held as aliases rather than separate entries, because telling them apart needs a task that asks for it.", "Described in 60 Wikipedia languages, which is a measure of how widely the thing is known, not of how important it is." ], "openQuestionsForResearch": [ "Which of the bundles below does a real task actually need, and which are ceremony?", "What does this thing have that the facets do not capture at all?", "Which neighbouring kind is most often confused with a electrical resistivity, and on what evidence are they told apart?" ], "whatItIsMadeOf": "an abstraction with no physical instance", "physicalCharacter": [ "Does nothing on its own; everything it does, something else did to it.", "These come from the domain this entry sits in rather than from the entry itself, so treat them as a first guess about the whole domain applied to one thing." ], "whatCanBeDoneWithIt": [ "observe it, measure it, record its state" ], "howItIsRecognised": [ "Nothing to see. What is recognised is an instance of it, and which instances count is exactly what is argued about." ], "relatedModels": [ { "relation": "covers", "note": "Finer kinds folded into this entry because telling them apart needs a task that asks for it. Each is a model waiting to be split out when one does.", "targets": [ "residual resistivity" ] } ], "standing": "Described in 60 Wikipedia languages, which measures how widely it is written about rather than how important or how common it is. 1 finer distinctions are held inside this entry as names rather than as separate models.", "structure": { "bundles": [ { "id": "identity-and-classification", "name": "Identity, naming and classification", "description": "How an agent tells one electrical resistivity from another, and a electrical resistivity from things that resemble it.", "rationale": "Recognition comes before every other claim. Without stable identity nothing else in the model can be trusted to be about the same thing twice.", "layers": [ { "id": "naming-and-identifiers", "name": "Names and identifiers", "description": "The names this thing goes by and the identifiers that survive translation and time.", "findings": [ { "id": "preferred-name-and-aliases", "name": "Preferred name, aliases and local names", "description": "Which name to use, which names mean the same thing, and which merely sound similar.", "questions": [ { "id": "preferred-name-and-aliases-q01", "text": "What identifies and describes the name of a electrical resistivity, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "preferred-name-and-aliases-q02", "text": "Who or what asserted this about the name of a electrical resistivity, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "preferred-name-and-aliases-q03", "text": "What may an agent decide or do once the name of a electrical resistivity is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] }, { "id": "stable-identifiers", "name": "Stable identifiers and external keys", "description": "Identifiers that keep pointing at this kind of thing across systems and languages.", "questions": [ { "id": "stable-identifiers-q01", "text": "What identifies and describes an identifier for a electrical resistivity, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "stable-identifiers-q02", "text": "Who or what asserted this about an identifier for a electrical resistivity, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "stable-identifiers-q03", "text": "What may an agent decide or do once an identifier for a electrical resistivity is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] }, { "id": "classification-and-granularity", "name": "Classification and granularity", "description": "Where a electrical resistivity sits among kinds, and how finely a task needs to cut it.", "findings": [ { "id": "kind-and-parents", "name": "Kind, parents and neighbouring kinds", "description": "The classes this thing belongs to and the ones it is next to.", "questions": [ { "id": "kind-and-parents-q01", "text": "What identifies and describes the kind of a electrical resistivity, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "kind-and-parents-q02", "text": "Who or what asserted this about the kind of a electrical resistivity, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "kind-and-parents-q03", "text": "What may an agent decide or do once the kind of a electrical resistivity is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] }, { "id": "distinguishing-features", "name": "Distinguishing features", "description": "What separates a electrical resistivity from the things most often confused with it.", "questions": [ { "id": "distinguishing-features-q01", "text": "What identifies and describes what distinguishes a electrical resistivity, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "distinguishing-features-q02", "text": "Who or what asserted this about what distinguishes a electrical resistivity, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "distinguishing-features-q03", "text": "What may an agent decide or do once what distinguishes a electrical resistivity is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] } ] }, { "id": "state-and-lifecycle", "name": "State and lifecycle", "description": "The states a electrical resistivity passes through and the events that move it between them.", "rationale": "Most decisions about a thing depend on what state it is in now, which is a claim with a time on it, not a property.", "layers": [ { "id": "lifecycle-stages", "name": "Lifecycle stages", "description": "From coming into existence to ceasing to be one of these.", "findings": [ { "id": "stages-and-transitions", "name": "Stages and transitions", "description": "The stages worth naming and what moves a electrical resistivity between them.", "questions": [ { "id": "stages-and-transitions-q01", "text": "What identifies and describes the lifecycle of a electrical resistivity, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "stages-and-transitions-q02", "text": "Who or what asserted this about the lifecycle of a electrical resistivity, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "stages-and-transitions-q03", "text": "What may an agent decide or do once the lifecycle of a electrical resistivity is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] }, { "id": "observations-and-status", "name": "Observations and current status", "description": "What is observed about a electrical resistivity, how often and by whom.", "findings": [ { "id": "observation-record", "name": "Observation record", "description": "How an observation of a electrical resistivity is recorded so that it can be superseded rather than overwritten.", "questions": [ { "id": "observation-record-q01", "text": "What identifies and describes an observation of a electrical resistivity, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "observation-record-q02", "text": "Who or what asserted this about an observation of a electrical resistivity, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "observation-record-q03", "text": "What may an agent decide or do once an observation of a electrical resistivity is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] } ] }, { "id": "definitions-in-contest", "name": "Definitions and who holds them", "description": "What electrical resistivity is taken to mean, and by whom.", "rationale": "When a field disagrees about a concept, the disagreement is the content. A model that picks one definition silently destroys the information.", "layers": [ { "id": "competing-definitions", "name": "Competing definitions", "description": "The main readings and the traditions behind them.", "findings": [ { "id": "definition-map", "name": "Definitions and their holders", "description": "Each definition with the school or body that holds it.", "questions": [ { "id": "definition-map-q01", "text": "Which definitions of electrical resistivity are in use, and which tradition or body holds each?", "kind": "definition" }, { "id": "definition-map-q02", "text": "What turns on the difference between them in practice?", "kind": "boundary" } ] } ] }, { "id": "operationalisation", "name": "Operationalisation", "description": "How it is measured or applied when it has to be.", "findings": [ { "id": "operational-record", "name": "Measures and proxies", "description": "Instruments and indicators used to stand in for it.", "questions": [ { "id": "operational-record-q01", "text": "How is electrical resistivity operationalised or measured in practice, and by what instrument?", "kind": "measurement" }, { "id": "operational-record-q02", "text": "What does that operationalisation leave out, and when does that matter?", "kind": "boundary" } ] } ] } ] }, { "id": "instances-and-use", "name": "Instances, use and consequence", "description": "What counts as an instance of electrical resistivity and what follows from calling something that.", "rationale": "Applying a concept is an act with consequences, so a model must say what the label licenses and what it does not.", "layers": [ { "id": "instances", "name": "What counts as an instance", "description": "Clear cases, borderline cases and non-cases.", "findings": [ { "id": "instance-tests", "name": "Tests for an instance", "description": "What would settle whether something falls under it.", "questions": [ { "id": "instance-tests-q01", "text": "What would settle whether something is an instance of electrical resistivity?", "kind": "boundary" }, { "id": "instance-tests-q02", "text": "Which borderline cases are argued about, and on what grounds?", "kind": "definition" } ] } ] }, { "id": "consequence", "name": "Consequence of application", "description": "Rights, duties or decisions that follow from the label.", "findings": [ { "id": "consequence-record", "name": "What the label licenses", "description": "What an agent may do once something is classified this way.", "questions": [ { "id": "consequence-record-q01", "text": "What follows practically once something is treated as electrical resistivity?", "kind": "action" }, { "id": "consequence-record-q02", "text": "What must an agent not infer from the label alone?", "kind": "action" } ] } ] } ] }, { "id": "provenance-and-evidence", "name": "Provenance, evidence and time", "description": "Where every claim about a electrical resistivity came from and when it held.", "rationale": "A claim without a source and a time cannot be superseded, only overwritten, and an agent that overwrites loses the ability to explain itself.", "layers": [ { "id": "source-and-authority", "name": "Source and authority", "description": "Who said it, on what evidence, and how strongly.", "findings": [ { "id": "claim-provenance", "name": "Claim provenance and confidence", "description": "The authority behind each claim about a electrical resistivity and how confident it is.", "questions": [ { "id": "claim-provenance-q01", "text": "What identifies and describes a claim about a electrical resistivity, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "claim-provenance-q02", "text": "Who or what asserted this about a claim about a electrical resistivity, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "claim-provenance-q03", "text": "What may an agent decide or do once a claim about a electrical resistivity is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] }, { "id": "time-and-versions", "name": "Time, versions and supersession", "description": "When a claim was true, when it was learnt, and what replaced it.", "findings": [ { "id": "validity-and-supersession", "name": "Validity period and supersession", "description": "How an old claim about a electrical resistivity is retired without being erased.", "questions": [ { "id": "validity-and-supersession-q01", "text": "What identifies and describes the validity of a claim about a electrical resistivity, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "validity-and-supersession-q02", "text": "Who or what asserted this about the validity of a claim about a electrical resistivity, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "validity-and-supersession-q03", "text": "What may an agent decide or do once the validity of a claim about a electrical resistivity is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] } ] } ] }, "statistics": { "bundles": 5, "layers": 10, "findings": 12, "questions": 32 } } } }