Table of contents
 Story
 Spotfire Dashboard
 Research Notes
 Slides
 Title Slide
 Introductions
 Slide 2 Roadmap
 Slide 3 Introductions
 Slide 4 What is QUDT?
 Slide 5 Motivations for "Model Driven" QUDT 1
 Slide 6 Motivations for "Model Driven" QUDT 2
 Slide 7 Motivations for "Model Driven" QUDT 3
 Slide 8 Motivations for "Model Driven" QUDT 4
 Slide 9 Motivations for "Model Driven" QUDT 5
 Slide 10 QUDT: "Real World" Benefits 1
 Slide 11 QUDT: "Real World" Benefits 2
 Quantities, Units and Dimensions 101
 NASA QUDT Handbook
 NASA QUDT Handbook
 Slide 24 Roadmap
 Slide 25 NASA QUDT Handbook HDBK1003R
 Slide 26 QUDT Scope
 Slide 27 QUDT: "Real World" Benefits
 Slide 28 Applicability
 Slide 29 NASA QUDT Handbook: Content
 Slide 30 NASA QUDT Handbook: Quantity Kind Domains
 Slide 31 NASA QUDT Handbook: Example Propulsion Quantity Kinds
 Slide 32 NASA QUDT Handbook: Example An ISO80000 QuantityKind
 Slide 33 QUDT Name, Identifier and Usage Rules
 Slide 34 Example of a Rule
 Slide 35 ModelDriven Traceability
 Slide 36 QUDT Industry & Standards Alignment
 Slide 37 QUDT Models ISO80000
 QUDT Ontology Models
 How the QUDT Handbook Was Produced
 Next Priorities
 QUDT
 Overview
 QUDT Ontologies and Vocabularies
 Ontology Class Structure
 Quantities, Quantity Kinds, and Quantity Values
 Quantity Kinds
 Unit of Measure
 Quantity Value
 Numerical Quantity Value
 Quantity Symbol
 Systems of Quantities and Units
 Base and Derived Quantity Kinds
 Quantity Dimensions
 Dimensionless Quantities and Units
 Allowed Units
 Example Quantity Kind and Unit Systems
 The SI System
 The CGS System
 CGS Units for Electricity and Magnetism
 Glossary
 Acknowledgements
 References
 Ontology Class Structure
 Instances
 Instances of qudt:AtomicPhysicsQuantityKind
 Instances of qudt:BiologyQuantityKind
 Instances of qudt:ChemistryQuantityKind
 quantity:AmountOfSubstance: Amount of Substance
 quantity:AmountOfSubstancePerUnitMass: Amount of Substance per Unit Mass
 quantity:AmountOfSubstancePerUnitVolume: Amount of Substance Per Unit Volume
 quantity:CatalyticActivity: Catalytic Activity
 quantity:Concentration: Concentration
 quantity:ElectricChargePerAmountOfSubstance: Electric Charge per Amount of Substance
 quantity:EnergyAndWorkPerMassAmountOfSubstance: Energy and Work per Mass Amount of Substance
 quantity:InverseAmountOfSubstance: Inverse Amount of Substance
 quantity:LengthMolarEnergy: Length Molar Energy
 quantity:MassAmountOfSubstance: Mass Amount of Substance
 quantity:MassAmountOfSubstanceTemperature: Mass Amount of Substance Temperature
 quantity:MolarEnergy: Molar Energy
 quantity:MolarMass: Molar Mass
 quantity:MolarVolume: Molar Volume
 quantity:MoleFraction: Mole Fraction
 quantity:MolecularMass: Molecular Mass
 quantity:TemperatureAmountOfSubstance: Temperature Amount of Substance
 quantity:Turbidity: Turbidity
 Instances of qudt:CommunicationsQuantityKind
 Instances of qudt:ElectricityAndMagnetismQuantityKind
 quantity:AuxillaryMagneticField: Auxillary Magnetic Field
 quantity:Capacitance: Capacitance
 quantity:CubicElectricDipoleMomentPerSquareEnergy: Cubic Electric Dipole Moment per Square Energy
 quantity:ElectricCharge: Electric Charge
 quantity:ElectricChargeLineDensity: Electric Charge Line Density
 quantity:ElectricChargePerAmountOfSubstance: Electric Charge per Amount of Substance
 quantity:ElectricChargePerArea: Electric Charge per Unit Area
 quantity:ElectricChargePerMass: Electric Charge per Mass
 quantity:ElectricChargeVolumeDensity: Electric Charge Volume Density
 quantity:ElectricConductivity: Electric Conductivity
 quantity:ElectricCurrent: Electric Current
 quantity:ElectricCurrentDensity: Electric Current Density
 quantity:ElectricCurrentPerAngle: Electric Current per Angle
 quantity:ElectricCurrentPerUnitEnergy: Electric Current per Unit Energy
 quantity:ElectricCurrentPerUnitLength: Electric Current per Unit Length
 quantity:ElectricDipoleMoment: Electric Dipole Moment
 quantity:ElectricDisplacementField: Electric Displacement Field
 quantity:ElectricField: Electric Field
 quantity:ElectricFlux: Electric Flux
 quantity:ElectricPotential: Electric Potential
 quantity:ElectricPower: Electric Power
 quantity:ElectricQuadrupoleMoment: Electric Quadrupole Moment
 quantity:ElectromotiveForce: Electromotive Force
 quantity:EnergyPerAreaElectricCharge: Energy per Area Electric Charge
 quantity:EnergyPerElectricCharge: Energy per Electric Charge
 quantity:EnergyPerSquareMagneticFluxDensity: Energy per Square Magnetic Flux Density
 quantity:ForcePerElectricCharge: Force per Electric Charge
 quantity:Inductance: Inductance
 quantity:InverseMagneticFlux: Inverse Magnetic Flux
 quantity:InversePermittivity: Inverse Permittivity
 quantity:LengthPerUnitElectricCurrent: Length per Unit Electric Current
 quantity:LengthPerUnitMagneticFlux: Length per Unit Magnetic Flux
 quantity:MagneticDipoleMoment: Magnetic Dipole Moment
 quantity:MagneticField: Magnetic Field
 quantity:MagneticFlux: Magnetic Flux
 quantity:MagneticFluxPerUnitLength: Magnetic Flux per Unit Length
 quantity:MagnetizationField: Magnetization Field
 quantity:MagnetomotiveForce: Magnetomotive Force
 quantity:MassPerElectricCharge: Mass per Electric Charge
 quantity:Permeability: Permeability
 quantity:Permittivity: Permittivity
 quantity:Polarizability: Polarizability
 quantity:PolarizationField: Polarization Field
 quantity:PowerPerElectricCharge: Power per Electric Charge
 quantity:QuarticElectricDipoleMomentPerCubicEnergy: Quartic Electric Dipole Moment per Cubic Energy
 quantity:Resistance: Resistance
 Instances of qudt:FinancialQuantityKind
 Instances of qudt:FluidMechanicsQuantityKind
 quantity:AtmosphericPressure: Atmospheric Pressure
 quantity:Circulation: Circulation
 quantity:DynamicPressure: Dynamic Pressure
 quantity:DynamicViscosity: Dynamic Viscosity
 quantity:KinematicViscosity: Kinematic Viscosity
 quantity:MolecularViscosity: Molecular Viscosity
 quantity:Pressure: Pressure
 quantity:ReynoldsNumber: Reynolds Number
 quantity:StaticPressure: Static Pressure
 quantity:TotalPressure: Total Pressure
 quantity:Viscosity: Viscosity
 quantity:Vorticity: Vorticity
 Instances of qudt:InformationQuantityKind
 Instances of qudt:MechanicsQuantityKind
 quantity:AngularMomentum: Angular Momentum
 quantity:AreaPerTime: Area per Time
 quantity:Density: Density
 quantity:EnergyAndWork: Energy and Work
 quantity:EnergyDensity: Energy Density
 quantity:EnergyInternal: Internal Energy
 quantity:EnergyKinetic: Kinetic Energy
 quantity:EnergyPerArea: Energy per Area
 quantity:Force: Force
 quantity:ForceMagnitude: Force Magnitude
 quantity:ForcePerArea: Force Per Area
 quantity:ForcePerAreaTime: Force Per Area Time
 quantity:ForcePerLength: Force per Unit Length
 quantity:Friction: Friction
 quantity:GravitationalAttraction: Gravitational Attraction
 quantity:InverseEnergy: Inverse Energy
 quantity:InverseSquareEnergy: Inverse Square Energy
 quantity:KineticEnergy: Kinetic Energy
 quantity:LengthByForce: Length Force
 quantity:LengthEnergy: Length Energy
 quantity:LengthMass: Length Mass
 quantity:LinearMomentum: Linear Momentum
 quantity:Mass: Mass
 quantity:MassPerArea: Mass per Area
 quantity:MassPerAreaTime: Mass per Area Time
 quantity:MassPerLength: Mass per Length
 quantity:MassPerTime: Mass per Time
 quantity:MolarAngularMomentum: Molar Angular Momentum
 quantity:MomentOfInertia: Moment of Inertia
 quantity:Momentum: Momentum
 quantity:PolarMomentOfInertia: Polar moment of inertia
 quantity:PotentialEnergy: Potential Energy
 quantity:Power: Power
 quantity:PowerArea: Power Area
 quantity:PowerAreaPerSolidAngle: Power Area per Solid Angle
 quantity:PowerPerArea: Power per Area
 quantity:PowerPerAreaAngle: Power per Area Angle
 quantity:SpecificEnergy: Specific Energy
 quantity:SpecificImpulseByMass: Specific Impulse by Mass
 quantity:SpecificImpulseByWeight: Specific Impulse by Weight
 quantity:SpecificVolume: Specific Volume
 quantity:SquareEnergy: Square Energy
 quantity:StandardGravitationalParameter: Standard Gravitational Parameter
 quantity:Thrust: Thrust
 quantity:ThrustToMassRatio: Thrust to Mass Ratio
 quantity:Torque: Torque
 quantity:Weight: Weight
 Instances of qudt:PhotometryQuantityKind
 quantity:Illuminance: Illuminance
 quantity:Luminance: Luminance
 quantity:LuminousEfficacy: Luminous Efficacy
 quantity:LuminousEmmitance: Luminous Emmitance
 quantity:LuminousEnergy: Luminous Energy
 quantity:LuminousFlux: Luminous Flux
 quantity:LuminousFluxPerArea: Luminous Flux per Area
 quantity:LuminousIntensity: Luminous Intensity
 Instances of qudt:QuantityKind
 Instances of qudt:QuantumMechanicsQuantityKind
 Instances of qudt:RadiologyQuantityKind
 Instances of qudt:RadiometryQuantityKind
 quantity:Irradiance: Irradiance
 quantity:Radiance: Radiance
 quantity:RadiantEmmitance: Radiant Emmitance
 quantity:RadiantEnergy: Radiant Energy
 quantity:RadiantFlux: Radiant Flux
 quantity:RadiantIntensity: Radiant Intensity
 quantity:Radiosity: Radiosity
 quantity:FirstMomentOfArea: First Moment of Area
 quantity:SecondMomentOfArea: Second Moment of Area
 quantity:Strain: Strain
 quantity:StrainEnergyDensity: Strain Energy Density
 quantity:Stress: Stress
 quantity:Tension: Tension
 Instances of qudt:SpaceAndTimeQuantityKind
 quantity:Acceleration: Acceleration
 quantity:Angle: Angle
 quantity:AngularAcceleration: Angular Acceleration
 quantity:AngularFrequency: Angular Frequency
 quantity:AngularVelocity: Angular Velocity
 quantity:Area: Area
 quantity:AreaAngle: Area Angle
 quantity:AreaTime: Area Time
 quantity:Curvature: Curvature
 quantity:DryVolume: Dry Volume
 quantity:Frequency: Frequency
 quantity:InverseLength: Inverse Length
 quantity:InverseVolume: Inverse Volume
 quantity:Length: Length
 quantity:LinearAcceleration: Linear Acceleration
 quantity:LinearVelocity: Linear Velocity
 quantity:LiquidVolume: Liquid Volume
 quantity:MachNumber: Mach Number
 quantity:NumberDensity: Number Density
 quantity:PlaneAngle: Plane Angle
 quantity:SolidAngle: Solid Angle
 quantity:Speed: Speed
 quantity:StochasticProcess: Stochastic Process
 quantity:Time: Time
 quantity:TimeSquared: Time Squared
 quantity:Velocity: Velocity
 quantity:Volume: Volume
 quantity:VolumePerUnitTime: Volume per Unit Time
 Instances of qudt:SystemOfQuantities
 quantity:SystemOfQuantities_CGS: CGS System of Quantities
 quantity:SystemOfQuantities_CGSEMU: CGSEMU System of Quantities
 quantity:SystemOfQuantities_CGSESU: CGSESU System of Quantities
 quantity:SystemOfQuantities_CGSGauss: CGSGauss System of Quantities
 quantity:SystemOfQuantities_Planck: Planck System of Quantities
 quantity:SystemOfQuantities_SI: International System of Quantities
 quantity:SystemOfQuantities_USCustomary: US Customary System of Quantities
 Instances of qudt:ThermodynamicsQuantityKind
 quantity:AreaTemperature: Area Temperature
 quantity:AreaThermalExpansion: Area Thermal Expansion
 quantity:AreaTimeTemperature: Area Time Temperature
 quantity:CoefficientOfHeatTransfer: Coefficient of Heat Transfer
 quantity:CompressibilityFactor: Compressibility Factor
 quantity:EnergyPerTemperature: Energy per Temperature
 quantity:Enthalpy: Enthalpy
 quantity:Heat: Heat
 quantity:HeatCapacity: Heat Capacity
 quantity:HeatCapacityRatio: Heat Capacity Ratio
 quantity:HeatFlowRate: Heat Flow Rate
 quantity:HeatFlowRatePerUnitArea: Heat Flow Rate per Unit Area
 quantity:InverseLengthTemperature: Inverse Length Temperature
 quantity:InverseTimeTemperature: Inverse Time Temperature
 quantity:LengthTemperature: Length Temperature
 quantity:LengthTemperatureTime: Length Temperature Time
 quantity:LinearThermalExpansion: Linear Thermal Expansion
 quantity:MassTemperature: Mass Temperature
 quantity:MolarHeatCapacity: Molar Heat Capacity
 quantity:PowerPerAreaQuarticTemperature: Power per Area Quartic Temperature
 quantity:SpecificHeatCapacity: Specific Heat Capacity
 quantity:SpecificHeatPressure: Specific Heat Pressure
 quantity:SpecificHeatVolume: Specific Heat Volume
 quantity:TemperaturePerMagneticFluxDensity: Temperature per Magnetic Flux Density
 quantity:TemperaturePerTime: Temperature per Time
 quantity:ThermalConductivity: Thermal Conductivity
 quantity:ThermalDiffusivity: Thermal Diffusivity
 quantity:ThermalEfficiency: Thermal Efficiency
 quantity:ThermalEnergy: Thermal Energy
 quantity:ThermalEnergyLength: Thermal Energy Length
 quantity:ThermalInsulance: Thermal Insulance
 quantity:ThermalResistance: Thermal Resistance
 quantity:ThermalResistivity: Thermal Resistivity
 quantity:ThermodynamicEntropy: Thermodynamic Entropy
 quantity:ThermodynamicTemperature: Temperature
 quantity:TimeTemperature: Time Temperature
 quantity:VolumeThermalExpansion: Volume Thermal Expansion
 quantity:VolumetricHeatCapacity: Volumetric Heat Capacity
 NEXT
 Story
 Spotfire Dashboard
 Research Notes
 Slides
 Title Slide
 Introductions
 Slide 2 Roadmap
 Slide 3 Introductions
 Slide 4 What is QUDT?
 Slide 5 Motivations for "Model Driven" QUDT 1
 Slide 6 Motivations for "Model Driven" QUDT 2
 Slide 7 Motivations for "Model Driven" QUDT 3
 Slide 8 Motivations for "Model Driven" QUDT 4
 Slide 9 Motivations for "Model Driven" QUDT 5
 Slide 10 QUDT: "Real World" Benefits 1
 Slide 11 QUDT: "Real World" Benefits 2
 Quantities, Units and Dimensions 101
 NASA QUDT Handbook
 NASA QUDT Handbook
 Slide 24 Roadmap
 Slide 25 NASA QUDT Handbook HDBK1003R
 Slide 26 QUDT Scope
 Slide 27 QUDT: "Real World" Benefits
 Slide 28 Applicability
 Slide 29 NASA QUDT Handbook: Content
 Slide 30 NASA QUDT Handbook: Quantity Kind Domains
 Slide 31 NASA QUDT Handbook: Example Propulsion Quantity Kinds
 Slide 32 NASA QUDT Handbook: Example An ISO80000 QuantityKind
 Slide 33 QUDT Name, Identifier and Usage Rules
 Slide 34 Example of a Rule
 Slide 35 ModelDriven Traceability
 Slide 36 QUDT Industry & Standards Alignment
 Slide 37 QUDT Models ISO80000
 QUDT Ontology Models
 How the QUDT Handbook Was Produced
 Next Priorities
 QUDT
 Overview
 QUDT Ontologies and Vocabularies
 Ontology Class Structure
 Quantities, Quantity Kinds, and Quantity Values
 Quantity Kinds
 Unit of Measure
 Quantity Value
 Numerical Quantity Value
 Quantity Symbol
 Systems of Quantities and Units
 Base and Derived Quantity Kinds
 Quantity Dimensions
 Dimensionless Quantities and Units
 Allowed Units
 Example Quantity Kind and Unit Systems
 The SI System
 The CGS System
 CGS Units for Electricity and Magnetism
 Glossary
 Acknowledgements
 References
 Ontology Class Structure
 Instances
 Instances of qudt:AtomicPhysicsQuantityKind
 Instances of qudt:BiologyQuantityKind
 Instances of qudt:ChemistryQuantityKind
 quantity:AmountOfSubstance: Amount of Substance
 quantity:AmountOfSubstancePerUnitMass: Amount of Substance per Unit Mass
 quantity:AmountOfSubstancePerUnitVolume: Amount of Substance Per Unit Volume
 quantity:CatalyticActivity: Catalytic Activity
 quantity:Concentration: Concentration
 quantity:ElectricChargePerAmountOfSubstance: Electric Charge per Amount of Substance
 quantity:EnergyAndWorkPerMassAmountOfSubstance: Energy and Work per Mass Amount of Substance
 quantity:InverseAmountOfSubstance: Inverse Amount of Substance
 quantity:LengthMolarEnergy: Length Molar Energy
 quantity:MassAmountOfSubstance: Mass Amount of Substance
 quantity:MassAmountOfSubstanceTemperature: Mass Amount of Substance Temperature
 quantity:MolarEnergy: Molar Energy
 quantity:MolarMass: Molar Mass
 quantity:MolarVolume: Molar Volume
 quantity:MoleFraction: Mole Fraction
 quantity:MolecularMass: Molecular Mass
 quantity:TemperatureAmountOfSubstance: Temperature Amount of Substance
 quantity:Turbidity: Turbidity
 Instances of qudt:CommunicationsQuantityKind
 Instances of qudt:ElectricityAndMagnetismQuantityKind
 quantity:AuxillaryMagneticField: Auxillary Magnetic Field
 quantity:Capacitance: Capacitance
 quantity:CubicElectricDipoleMomentPerSquareEnergy: Cubic Electric Dipole Moment per Square Energy
 quantity:ElectricCharge: Electric Charge
 quantity:ElectricChargeLineDensity: Electric Charge Line Density
 quantity:ElectricChargePerAmountOfSubstance: Electric Charge per Amount of Substance
 quantity:ElectricChargePerArea: Electric Charge per Unit Area
 quantity:ElectricChargePerMass: Electric Charge per Mass
 quantity:ElectricChargeVolumeDensity: Electric Charge Volume Density
 quantity:ElectricConductivity: Electric Conductivity
 quantity:ElectricCurrent: Electric Current
 quantity:ElectricCurrentDensity: Electric Current Density
 quantity:ElectricCurrentPerAngle: Electric Current per Angle
 quantity:ElectricCurrentPerUnitEnergy: Electric Current per Unit Energy
 quantity:ElectricCurrentPerUnitLength: Electric Current per Unit Length
 quantity:ElectricDipoleMoment: Electric Dipole Moment
 quantity:ElectricDisplacementField: Electric Displacement Field
 quantity:ElectricField: Electric Field
 quantity:ElectricFlux: Electric Flux
 quantity:ElectricPotential: Electric Potential
 quantity:ElectricPower: Electric Power
 quantity:ElectricQuadrupoleMoment: Electric Quadrupole Moment
 quantity:ElectromotiveForce: Electromotive Force
 quantity:EnergyPerAreaElectricCharge: Energy per Area Electric Charge
 quantity:EnergyPerElectricCharge: Energy per Electric Charge
 quantity:EnergyPerSquareMagneticFluxDensity: Energy per Square Magnetic Flux Density
 quantity:ForcePerElectricCharge: Force per Electric Charge
 quantity:Inductance: Inductance
 quantity:InverseMagneticFlux: Inverse Magnetic Flux
 quantity:InversePermittivity: Inverse Permittivity
 quantity:LengthPerUnitElectricCurrent: Length per Unit Electric Current
 quantity:LengthPerUnitMagneticFlux: Length per Unit Magnetic Flux
 quantity:MagneticDipoleMoment: Magnetic Dipole Moment
 quantity:MagneticField: Magnetic Field
 quantity:MagneticFlux: Magnetic Flux
 quantity:MagneticFluxPerUnitLength: Magnetic Flux per Unit Length
 quantity:MagnetizationField: Magnetization Field
 quantity:MagnetomotiveForce: Magnetomotive Force
 quantity:MassPerElectricCharge: Mass per Electric Charge
 quantity:Permeability: Permeability
 quantity:Permittivity: Permittivity
 quantity:Polarizability: Polarizability
 quantity:PolarizationField: Polarization Field
 quantity:PowerPerElectricCharge: Power per Electric Charge
 quantity:QuarticElectricDipoleMomentPerCubicEnergy: Quartic Electric Dipole Moment per Cubic Energy
 quantity:Resistance: Resistance
 Instances of qudt:FinancialQuantityKind
 Instances of qudt:FluidMechanicsQuantityKind
 quantity:AtmosphericPressure: Atmospheric Pressure
 quantity:Circulation: Circulation
 quantity:DynamicPressure: Dynamic Pressure
 quantity:DynamicViscosity: Dynamic Viscosity
 quantity:KinematicViscosity: Kinematic Viscosity
 quantity:MolecularViscosity: Molecular Viscosity
 quantity:Pressure: Pressure
 quantity:ReynoldsNumber: Reynolds Number
 quantity:StaticPressure: Static Pressure
 quantity:TotalPressure: Total Pressure
 quantity:Viscosity: Viscosity
 quantity:Vorticity: Vorticity
 Instances of qudt:InformationQuantityKind
 Instances of qudt:MechanicsQuantityKind
 quantity:AngularMomentum: Angular Momentum
 quantity:AreaPerTime: Area per Time
 quantity:Density: Density
 quantity:EnergyAndWork: Energy and Work
 quantity:EnergyDensity: Energy Density
 quantity:EnergyInternal: Internal Energy
 quantity:EnergyKinetic: Kinetic Energy
 quantity:EnergyPerArea: Energy per Area
 quantity:Force: Force
 quantity:ForceMagnitude: Force Magnitude
 quantity:ForcePerArea: Force Per Area
 quantity:ForcePerAreaTime: Force Per Area Time
 quantity:ForcePerLength: Force per Unit Length
 quantity:Friction: Friction
 quantity:GravitationalAttraction: Gravitational Attraction
 quantity:InverseEnergy: Inverse Energy
 quantity:InverseSquareEnergy: Inverse Square Energy
 quantity:KineticEnergy: Kinetic Energy
 quantity:LengthByForce: Length Force
 quantity:LengthEnergy: Length Energy
 quantity:LengthMass: Length Mass
 quantity:LinearMomentum: Linear Momentum
 quantity:Mass: Mass
 quantity:MassPerArea: Mass per Area
 quantity:MassPerAreaTime: Mass per Area Time
 quantity:MassPerLength: Mass per Length
 quantity:MassPerTime: Mass per Time
 quantity:MolarAngularMomentum: Molar Angular Momentum
 quantity:MomentOfInertia: Moment of Inertia
 quantity:Momentum: Momentum
 quantity:PolarMomentOfInertia: Polar moment of inertia
 quantity:PotentialEnergy: Potential Energy
 quantity:Power: Power
 quantity:PowerArea: Power Area
 quantity:PowerAreaPerSolidAngle: Power Area per Solid Angle
 quantity:PowerPerArea: Power per Area
 quantity:PowerPerAreaAngle: Power per Area Angle
 quantity:SpecificEnergy: Specific Energy
 quantity:SpecificImpulseByMass: Specific Impulse by Mass
 quantity:SpecificImpulseByWeight: Specific Impulse by Weight
 quantity:SpecificVolume: Specific Volume
 quantity:SquareEnergy: Square Energy
 quantity:StandardGravitationalParameter: Standard Gravitational Parameter
 quantity:Thrust: Thrust
 quantity:ThrustToMassRatio: Thrust to Mass Ratio
 quantity:Torque: Torque
 quantity:Weight: Weight
 Instances of qudt:PhotometryQuantityKind
 quantity:Illuminance: Illuminance
 quantity:Luminance: Luminance
 quantity:LuminousEfficacy: Luminous Efficacy
 quantity:LuminousEmmitance: Luminous Emmitance
 quantity:LuminousEnergy: Luminous Energy
 quantity:LuminousFlux: Luminous Flux
 quantity:LuminousFluxPerArea: Luminous Flux per Area
 quantity:LuminousIntensity: Luminous Intensity
 Instances of qudt:QuantityKind
 Instances of qudt:QuantumMechanicsQuantityKind
 Instances of qudt:RadiologyQuantityKind
 Instances of qudt:RadiometryQuantityKind
 quantity:Irradiance: Irradiance
 quantity:Radiance: Radiance
 quantity:RadiantEmmitance: Radiant Emmitance
 quantity:RadiantEnergy: Radiant Energy
 quantity:RadiantFlux: Radiant Flux
 quantity:RadiantIntensity: Radiant Intensity
 quantity:Radiosity: Radiosity
 quantity:FirstMomentOfArea: First Moment of Area
 quantity:SecondMomentOfArea: Second Moment of Area
 quantity:Strain: Strain
 quantity:StrainEnergyDensity: Strain Energy Density
 quantity:Stress: Stress
 quantity:Tension: Tension
 Instances of qudt:SpaceAndTimeQuantityKind
 quantity:Acceleration: Acceleration
 quantity:Angle: Angle
 quantity:AngularAcceleration: Angular Acceleration
 quantity:AngularFrequency: Angular Frequency
 quantity:AngularVelocity: Angular Velocity
 quantity:Area: Area
 quantity:AreaAngle: Area Angle
 quantity:AreaTime: Area Time
 quantity:Curvature: Curvature
 quantity:DryVolume: Dry Volume
 quantity:Frequency: Frequency
 quantity:InverseLength: Inverse Length
 quantity:InverseVolume: Inverse Volume
 quantity:Length: Length
 quantity:LinearAcceleration: Linear Acceleration
 quantity:LinearVelocity: Linear Velocity
 quantity:LiquidVolume: Liquid Volume
 quantity:MachNumber: Mach Number
 quantity:NumberDensity: Number Density
 quantity:PlaneAngle: Plane Angle
 quantity:SolidAngle: Solid Angle
 quantity:Speed: Speed
 quantity:StochasticProcess: Stochastic Process
 quantity:Time: Time
 quantity:TimeSquared: Time Squared
 quantity:Velocity: Velocity
 quantity:Volume: Volume
 quantity:VolumePerUnitTime: Volume per Unit Time
 Instances of qudt:SystemOfQuantities
 quantity:SystemOfQuantities_CGS: CGS System of Quantities
 quantity:SystemOfQuantities_CGSEMU: CGSEMU System of Quantities
 quantity:SystemOfQuantities_CGSESU: CGSESU System of Quantities
 quantity:SystemOfQuantities_CGSGauss: CGSGauss System of Quantities
 quantity:SystemOfQuantities_Planck: Planck System of Quantities
 quantity:SystemOfQuantities_SI: International System of Quantities
 quantity:SystemOfQuantities_USCustomary: US Customary System of Quantities
 Instances of qudt:ThermodynamicsQuantityKind
 quantity:AreaTemperature: Area Temperature
 quantity:AreaThermalExpansion: Area Thermal Expansion
 quantity:AreaTimeTemperature: Area Time Temperature
 quantity:CoefficientOfHeatTransfer: Coefficient of Heat Transfer
 quantity:CompressibilityFactor: Compressibility Factor
 quantity:EnergyPerTemperature: Energy per Temperature
 quantity:Enthalpy: Enthalpy
 quantity:Heat: Heat
 quantity:HeatCapacity: Heat Capacity
 quantity:HeatCapacityRatio: Heat Capacity Ratio
 quantity:HeatFlowRate: Heat Flow Rate
 quantity:HeatFlowRatePerUnitArea: Heat Flow Rate per Unit Area
 quantity:InverseLengthTemperature: Inverse Length Temperature
 quantity:InverseTimeTemperature: Inverse Time Temperature
 quantity:LengthTemperature: Length Temperature
 quantity:LengthTemperatureTime: Length Temperature Time
 quantity:LinearThermalExpansion: Linear Thermal Expansion
 quantity:MassTemperature: Mass Temperature
 quantity:MolarHeatCapacity: Molar Heat Capacity
 quantity:PowerPerAreaQuarticTemperature: Power per Area Quartic Temperature
 quantity:SpecificHeatCapacity: Specific Heat Capacity
 quantity:SpecificHeatPressure: Specific Heat Pressure
 quantity:SpecificHeatVolume: Specific Heat Volume
 quantity:TemperaturePerMagneticFluxDensity: Temperature per Magnetic Flux Density
 quantity:TemperaturePerTime: Temperature per Time
 quantity:ThermalConductivity: Thermal Conductivity
 quantity:ThermalDiffusivity: Thermal Diffusivity
 quantity:ThermalEfficiency: Thermal Efficiency
 quantity:ThermalEnergy: Thermal Energy
 quantity:ThermalEnergyLength: Thermal Energy Length
 quantity:ThermalInsulance: Thermal Insulance
 quantity:ThermalResistance: Thermal Resistance
 quantity:ThermalResistivity: Thermal Resistivity
 quantity:ThermodynamicEntropy: Thermodynamic Entropy
 quantity:ThermodynamicTemperature: Temperature
 quantity:TimeTemperature: Time Temperature
 quantity:VolumeThermalExpansion: Volume Thermal Expansion
 quantity:VolumetricHeatCapacity: Volumetric Heat Capacity
 NEXT
Story
Data Science for QUDT
The QUDT Ontologies, and derived XML Vocabularies, are being developed by TopQuadrant and NASA. Originally, they were developed for the NASA Exploration Initiatives Ontology Models (NExIOM) project, a Constellation Program initiative at the AMES Research Center (ARC). They now are the basis of the NASA QUDT Handbook to be published by NASA Headquarters.
The results are:
 QUDT  Quantities, Units, Dimensions and Data Types Ontologies: http://www.qudt.org/
 Last UPDATED August 24, 2013
 QUDT Quantities, Units, Dimensions and dataTypes  public repository: https://github.com/qudt/qudtpublicrepo
 Last updated: May 4, 2014
 NASA QUDT Handbook PowerPoint Slides
 October 10, 2013
Data Science can repurpose this into a NASA Data Science Data Publication. The results are:
Knowledge Base (this page): Use Google Chrome Find
Spreadsheet: Use Excel Find
Spotfire: Use Spotfire Find
Additional Refinements:
 Add Unit Instances: DONE
 Redirect the Internal URLs: IN PROCESS
 Other: Slides
Conclusions and Recommendations
 Since 2009, NASA has been developing a machineprocessable representation of Quantities, Units of Measure and Data Types (QUDT). Source: Hodgson, 2014, Presentation.
 The NASA QUDT Handbook (HDBK1003R) which, now over 3,500 pages, is generated from the QUDT models. Source: Hodgson, 2014, Presentation.
 The TopQuadrant work on QUDT and the NASA QUDT Handbook work seems to have stalled.
 The Semantic Community Data Science Audit of the TopQuadrant work on QUDT found some gaps and errors, which we are currently trying to understand and fix.
 The QUDT needs to be rendered in a MindTouch, Excel, and Spotfire Data Science Data Publication to be more reuseable, which we have started.
Spotfire Dashboard
For Internet Explorer Users and Those Wanting Full Screen Display Use: Web Player Get Spotfire iPad App
Research Notes
https://github.com/qudt/qudtpublicrepo
http://ontolog.cim3.net%2Ffile%2Fwork%2FOntologyBasedStandards%2F20131010_CaseforQUOMOS%2FNASAQUDTHandbookv10RalphHodgson_20131010.pdf
Slides
Introductions
Quantities, Units and Dimensions 101
NASA QUDT Handbook
NASA QUDT Handbook
QUDT Ontology Models
How the QUDT Handbook Was Produced
QUDT
Source: http://www.qudt.org/
Quantities, Units, Dimensions and Data Types Ontologies
March 18, 2014
 Authors:
 Ralph Hodgson, TopQuadrant, Inc.
 Paul J. Keller, NASA AMES Research Center
 Jack Hodges
 Jack Spivak
Overview
The QUDT Ontologies, and derived XML Vocabularies, are being developed by TopQuadrant and NASA. Originally, they were developed for the NASA Exploration Initiatives Ontology Models (NExIOM) project, a ConstellationPROGRAM initiative at the AMES Research Center (ARC). They now for the basis of the NASA QUDT Handbook to be published by NASA Headquarters.
Status
The current release of the QUDT ontologies is version 1.1 and may be DOWNLOADED from the QUDT Catalog, which can also be accessed from LinkedModel.org.
Release 2 of QUDT will be published incrementally. Currently the content, in the form of the NASA QUDT Handbook, is being reviewed by NASA.
A presentation on QUDT can be found at scribd.com/ralphtq.
Goals
The goals of QUDT are to provide:
 A standardized consistent vocabulary, focused on terminology used in science and engineering.
 The vocabulary in this standard consists of standardized terminology, definitions, identifiers, and information models.
 The intent is to use this vocabulary with a variety of encodings, formats, and data definitions, so it is defined independent of those forms.
 Some or all portions of this vocabulary will be of interest to various users and applications, depending on the use case and policy mandates.
 It is expected that a large set of existing corpus will not be changed, and so this standard serves as a critical “Rosetta Stone” to reference existing uses of quantities, units, dimensions, and types to a consistent base.
 A set of consistent coded identifiers, for human and machine use.
 In the same way that modern digital COMPUTERS could not represent and process meaningful information without the use of standards such as ASCII and Unicode, this standard also introduces a similar coding scheme, for a like purpose.
 Assigning an explicit designator (e.g. ASCII uses a numerical value for each letter of the alphabet, numbers, and punctuation) to quantities, units, dimensions, and types is used to provide a robust, unequivocal method of identification of digital information by computer SOFTWARE and hardware.
 This definitional approach provides generalized usability for both humans and machines, avoiding problems with uncertainty and misinterpretation.
 A collection of foundational vocabularies that can serve a variety of applications. Some examples include:
 providing terminology and vocabulary definitions for Documents and Publications. Define consistent terminology for general PROGRAM and Project documentation, technical reports, conference papers, guides, drawings, technical specifications, engineering and process documentation, etc.
 defining SOFTWARE code documentation, pragmas and/or comments, and independent reference documentation. Referencing system and software variables and constants provides explicit, unambiguous definitions that can be used for data exchanges, semantic consistency, automated checking, software reuse, and more robust search and discovery.
 improving the quality of SOFTWARE interfaces, web services, and data exchanges. The model basis of this standard can be used by other SOFTWARE, or to build software, for a variety of purposes; model creation, validation, compilation and runtime checking, translation and transformation, data exchange definitions, etc.
 generating schema specifications and data definitions in other formalisms. Examples include database, data file (ex, XML) schema, software application data structures, codelists, and other controlled vocabularies.
 enabling files, datasets, messages, communications and Data Exchange Packages to use consistent terms and constructs when defining elements of datasets and messages in a variety of forms and formats.
 A framework designed for extensibility and evolution, but modelbased (instead of just a typical dictionary) and governed.
 The authors recognize that any given release will not have every possible quantity, unit, dimension, or type that a user may need.
 The framework has been designed to grow in a consistent manner.
QUDT Ontologies and Vocabularies
The QUDT Specification is more than a list of quantities, units, dimensions, data types, enumerations, and structures. In order to provide for interoperability and data exchange between information systems, the specification needs to be available in a machine processable form, with no ambiguities.
For these reasons, the QUDT approach to specifying quantities, units, dimensions, data types, enumerations, and other data structures is to use precise semantically grounded specifications in an ontology model with translation into machineprocessable representations.
Ontologies provide the objectoriented strengths of encapsulation, inheritance, and polymorphism, strengths which are unavailable in other structured modeling approaches. The characteristics modeled in QUDT require a modelbased approach because they are functionally dependent.
Modeling one without modeling its dependency on the other requires that the understanding of those dependencies be carried by the observer, which injects ambiguity into the modeling approach. These models (dimensions, coordinate systems, etc.), like everything else, are hierarchical, so using a language to model them which doesn't support inheritance imposes constraints on the models and their use which, again, results in ambiguity.
QUDT semantics are based on dimensional analysis expressed in the OWL Web Ontology Language (OWL). The dimensional approach relates each unit to a system of base units using numeric factors and a vector of exponents defined over a set of fundamental dimensions. In this way, the role of each base unit in the derived unit is precisely defined. A further relationship establishes the semantics of units and quantity kinds. By this means, QUDT supports reasoning over quantities as well as units.
All QUDT models may be translated into other representations for machine processing, or other programming language structures according to need.
An overview of the ontological structure of QUDT is provided below.
Ontology Class Structure
The diagram below, exported from TopBraid Composer, illustrates the main class structure of the QUDT ontology in OWL.
Quantities, Quantity Kinds, and Quantity Values
A Quantity is an observable property of an object, event or system that can be measured and quantified numerically. Quantities are differentiated by two attributes which together comprise the essential parameters needed to formalize the structure of quantities: kind andmagnitude. The kind attribute of a quantity identifies the observable property quantified, e.g. length, force, frequency; the magnitude of the quantity expresses its relative size compared to other quantities of the same kind.
For example, the speed of light in a vacuum and the escape velocity of the Earth are both quantities of the kind speed but are of different magnitudes. The speed of light in a vacuum is greater than the escape velocity of the Earth. More generally, the speed of light in a vacuum is comparable to the escape velocity of the Earth. Thus, if two quantities are of the same kind, their magnitudes can be compared and ordered. However, the same is not true if the quantities are of different kinds. There is no intrinsic way to compare the magnitude of a quantity of mass with the magnitude of a quantity of length.
Quantities may arise from definition or convention, or they may be the result of one or a series of experiments and measurements. In the first case, the quantity is exact; in the second case, measurement uncertainty cannot be discounted so the expression of a quantity's magnitude must account for the parameters of uncertainty.
Quantity Kinds
A Quantity Kind is any observable property that can be measured and quantified numerically. Familiar examples include physical properties such as length, mass, time, force, energy, power, electric charge, etc. Less familiar examples include currency, interest rate, price to EARNING ratio, and information capacity.
Unit of Measure
A Unit of Measure or Unit is a particular quantity of a given kind that has been chosen as a scale for measuring other quantities of the same kind. For example, the Meter is a quantity of length that has been empirically defined by the BIPM. Any quantity of length can be expressed as a number multiplied by the unit meter.
More formally, the value of a quantity Q with respect to a unit (U) is expressed as the scalar multiple of a real number (n) and U:
Q = nU
Quantity Value
A quantity value expresses the magnitude and kind of a quantity and is given by the product of a numerical value n
and a unit of measure U
. The number multiplying the unit is referred to as the numerical value of the quantity expressed in that unit. Refer to NIST SP 811 section 7 for more on quantity values.
Numerical Quantity Value
The numerical value of a quantity is the numerical value without the unit of measure. For example, the value of Planck's constant in JouleSeconds (J s) is approximately 6.62606896E34
, whereas the value in ErgSeconds (erg s) is approximately 6.62606896E27
. The numerical value of a quantity n
is a mere scaling factor for the unit U
. It is the product of the two, n X U
, that expresses the value (magnitude and quantity kind) of the unit.
Quantity Symbol
In the same way that a unit has a symbol, a quantity also has a symbol. For example a quantity of the (quantity) kind mass usually has the symbolm
. Each quantity kind has a recommended symbol associated with it. For example, t
for time, Q
for charge, v
for velocity, T
for temperature, P
for power and p
for pressure. A quantity usually receives a symbol that consists of the symbol of its quantity kind and an optional subscript. Symbols for quantities should be chosen ACCORDING to the international recommendations from ISO/IEC~80000, the IUPAP red book and the IUPAC green book.
The OWL model for the classes qudt:QuantityKind, qudt:Quantity, qudt:QuantityValue, qudt:Unit is shown below.
Systems of Quantities and Units
The art and science of defining, standardizing, and organizing quantity kinds and units is ancient and modern. Today, scientific boards and standards bodies maintain rigorous definitions for quantity kinds and units. The definitions of quantity kinds and their relationships are derived from physical laws and mathematical transformations. Units are defined by experimental observations, by the application of physical laws, as ratios of fundamental physical constants, or by reference. One significant advance in the modern treatment of metrology has been the use of logic and mathematics to organize quantity kinds and units into systems and to analyze the relationships between them.
A system of quantity kinds is a set of one or more quantity kinds together with a set of zero or more algebraic equations that define relationships between quantity kinds in the set. In the physical sciences, the equations relating quantity kinds are typically physical laws and definitional relations, and constants of proportionality. Examples include Newton’s First Law of Motion, Coulomb’s Law, and the definition of velocity as the instantaneous change in position.
In almost all cases, the system identifies a subset of base quantity kinds. The base set is chosen so that all other quantity kinds of interest can be derived from the base quantity kinds and the algebraic equations.
A system of units is a set of units which are chosen as the reference scales for some set of quantity kinds together with the definitions of each unit. Units may be defined by experimental observation or by proportion to another unit not included in the system. If the unit system is explicitly associated with a quantity kind system, then the unit system must define at least one unit for each quantity kind.
Base and Derived Quantity Kinds
Many systems of quantity kinds identify a special subset of the included quantity kinds called the base quantity kinds. Base quantity kinds are typically chosen so that no base quantity kind can be expressed as an algebraic relation of one or more other base quantity kinds using only the constituent equations included in the system. A quantity kind that can be expressed as an algebraic relation of one or more base quantity kind is called a derived quantity kind. Thus, in any quantity kind system, the base set and derived set are disjoint.
Similarly, unit systems may distinguish between base units and derived units. A base unit is a unit of measurement for a base quantity, and a derived unit is a unit of measurement for a derived quantity. Unit systems define at least one base unit for each base quantity and at least one derived unit for each derived quantity.
Quantity Dimensions
Quantity kind systems that define base and derived sets have certain mathematical properties that permit quantity kinds to be manipulated symbolically. The construction goes as follows: Assign a distinct dimension symbol to each base quantity kind. For each derived quantity kind, take the formula that expresses it in terms of the base quantity kinds and replace every occurrence of a base quantity with its symbol. This is the dimension symbol for the derived quantity kind. In this way, every quantity kind maps to a dimension symbol of the form:
dim Q = (B_{1})^{d1}(B_{2})^{d2}…(B_{n})^{dn}
Here {B_{1},…,B_{n}} are the dimension symbols for the base quantities and {d_{1},…,d_{n}} are rational numbers. Typically, the values of the d_{i} are between 3 and 3, however magnitudes as high as 7 are required to cover the range of quantity kinds currently defined. Using the multiplication identity for exponents A^{n}A^{m} = A^{n+m} one can show that the set of dimension symbols is homomorphic to an ndimensional vector space over the rational numbers. Multiplication of quantity kinds corresponds to vector addition, division corresponds to vector subtraction, and inverting a quantity kind corresponds to COMPUTING the additive inverse of its dimension vector.
In some cases, distinct quantity kinds may have the same dimension symbol. This often occurs in cases where physical laws are discovered and formalized independently of each other, but reduce to the same base quantity kinds. A commonly quoted example is the dimensional equivalence of mechanical torque and energy. Both have the same dimensions (L^{2}M^{1}T^{2}) but are defined very differently.
One consequence of the equivalence is that the same units of measure are applicable to both. A salient difference between the two in this example is that torque is a pseudovector while energy is a scalar. However, this distinction (value type) is not accounted for in the quantity kind system formalism.
The OWL model of Dimensions is illustrated below.
Dimensionless Quantities and Units
Dimensionless Quantities, or quantities of dimension 1, are those for which all the exponents of the factors corresponding to the base quantities in its quantity dimension are zero. Counts, ratios and plane angles are examples of dimensionless quantities.
Allowed Units
Some unit systems identify units that are not defined within the system but are allowed to be used in combination with units that are defined within the system. Allowed units must be commensurable with some defined unit of the system, so that quantities expressed in the allowed unit may be converted to a defined unit. The SI System explicitly allows a number of nonSI units.
Example Quantity Kind and Unit Systems
This section contains tables of several of the quantity kind and unit systems that are currently defined in the ontology. The table columns are:

Category – Either “Base᾿, “Derived᾿, or “TBD᾿

Quantity Kind – The name of the quantity kind

Quantity QName – The QName of the quantity kind

Dimension Symbol – The dimension symbol for the quantity kind. For derived quantity kinds, the symbol is a linear combination of the base quantity symbols, as described above.

Unit – The name of a unit in the unit system that is the defined unit for the quantity kind

Unit QName – The QName of the unit

Unit Symbol – A common symbol or abbreviation for the unit
The SI System
SI Base and Derived Quantities and Units
Category  Quantity Kind  QName  Dimension Symbol  Unit  QName  Unit Symbol 
Base  Dimensionless  U  Unity  unit:Unity My Note: Did Not Find  U  
Length  L  Meter  m  
Mass  M  Kilogram  kg  
Time  T  Second  s  
Electric Current  I  Ampere  unit:Ampere My Note: Tested ReLinks to Here  A  
Temperature  Θ  Kelvin  K  
Amount of Substance  N  Mole  mol  
Luminous Intensity  J  Candela  cd  
Derived  Absorbed Dose  L^{2}T^{2}  Gray  Gy  
Absorbed Dose Rate  L^{2}T^{3}  Gray per second  Gy/s  
Activity  T^{1}  Becquerel  Bq  
Amount of Substance Per Unit Volume  L^{3}N^{1}  Mole per cubic meter  mol/m^3  
Amount of Substance per Unit Mass  M^{3}N^{1}  Mole per kilogram  mol/kg  
Angular Acceleration  U^{1}T^{2}  Radian per second squared  rad/s^2  
Angular Mass  quantity:AngularMass My Note: Did Not Find  L^{2}M^{1}  Kilogram Meter Squared  kgm^2  
Angular Momentum  L^{2}M^{1}T^{1}  Joule Second  J s  
Angular Velocity  U^{1}T^{1}  Radian per second  rad/s  
Area  L^{2}  Square meter  m^2  
Area Angle  U^{1}L^{2}  Square meter steradian  m^2sr  
Area Temperature  L^{2}Θ^{1}  Square meter kelvin  m^2K  
Area Thermal Expansion  L^{2}Θ^{1}  Square meter per kelvin  m^2/K  
Capacitance  L^{2}M^{1}T^{4}I^{2}  Farad  F  
Catalytic Activity  T^{1}N^{1}  Katal  kat  
Coefficient of Heat Transfer  M^{1}T^{3}Θ^{1}  Watt per square meter kelvin  W/(m^2K)  
Density  L^{3}M^{1}  Kilogram per cubic meter  kg/m^3  
Dose Equivalent  L^{2}T^{2}  Sievert  Sv  
Dynamic Viscosity  L^{1}M^{1}T^{1}  Pascal second  Pas  
Electric Charge  T^{1}I^{1}  Coulomb  C  
Electric Charge Line Density  L^{1}T^{1}I^{1}  Coulomb per meter  C/m  
Electric Charge Volume Density  L^{3}T^{1}I^{1}  Coulomb per cubic meter  C/m^3  
Electric Charge per Amount of Substance  T^{1}I^{1}N^{1}  Coulomb per mole  C/mol  
Electric Current Density  L^{2}I^{1}  Ampere per square meter  A/m^2  
Electric Current per Angle  quantity:CurrentPerAngle My Note: Did Not Find  U^{1}I^{1}  Ampere per radian  A/rad  
Electric Dipole Moment  L^{1}T^{1}I^{1}  Coulomb meter  Cm  
Electric Field Strength  quantity:ElectricFieldStrength My Note: Did Not Find  L^{1}M^{1}T^{3}I^{1}  Volt per Meter  V/m  
Electric Flux Density  quantity:ElectricFluxDensity My Note: Did Not Find  L^{2}T^{1}I^{1}  Coulomb per Square Meter  C/m^2  
Electrical Conductivity  quantity:ElectricalConductivity My Note: Did Not Find  L^{2}M^{1}T^{3}I^{2}  Siemens  S  
Electromotive Force  L^{2}M^{1}T^{3}I^{1}  Volt  V  
Energy Density  L^{1}M^{1}T^{2}  Joule per cubic meter  J/m^3  
Energy and Work  L^{2}M^{1}T^{2}  Joule  J  
Energy per Unit Area  quantity:EnergyPerUnitArea My Note: Did Not Find  M^{1}T^{2}  Joule per square meter  J/m^2  
Exposure  M^{1}T^{1}I^{1}  Coulomb per kilogram  C/kg  
Force  L^{1}M^{1}T^{2}  Newton  N  
Force per Electric Charge  L^{1}M^{1}T^{3}I^{1}  Newton per coulomb  N/C  
Force per Unit Length  quantity:ForcePerUnitLength My Note: Did Not Find  M^{1}T^{2}  Newton per meter  N/m  
Frequency  T^{1}  Hertz  Hz  
Inverse second time  s^1  
Gravitational Attraction  L^{3}M^{1}T^{2}  Cubic meter per kilogram second squared  m^3/(kgs^2)  
Heat Capacity and Entropy  quantity:HeatCapacityAndEntropy My Note: Did Not Find  L^{2}M^{1}T^{2}Θ^{1}  Joule per kelvin  J/K  
Heat Flow Rate  L^{2}M^{1}T^{3}  Watt  W  
Heat Flow Rate per Unit Area  M^{1}T^{3}  Watt per square meter  W/m^2  
Illuminance  U^{1}L^{2}J^{1}  Lux  lx  
Inductance  L^{2}M^{1}T^{2}I^{2}  Henry  H  
Inverse Amount of Substance  N^{1}  Per mole  mol^(1)  
Inverse Permittivity  L^{3}M^{1}T^{4}I^{2}  Meter per farad  m/F  
Kinematic Viscosity  L^{2}T^{1}  Square meter per second  m^2/sec  
Length Mass  L^{1}M^{1}  Meter kilogram  mkg  
Length Temperature  L^{1}Θ^{1}  Meter kelvin  mK  
Linear Acceleration  L^{1}T^{2}  Meter per second squared  m/s^2  
Linear Momentum  L^{1}M^{1}T^{1}  Kilogram Meter Per Second  kgm/s  
Linear Thermal Expansion  L^{1}Θ^{1}  Meter per kelvin  m/K  
Linear Velocity  L^{1}T^{1}  Meter per second  m/s  
Luminance  L^{2}J^{1}  Candela per square meter  cd/m^2  
Luminous Flux  U^{1}J^{1}  Lumen  lm  
Magnetic Dipole Moment  L^{2}I^{1}  Joule per Tesla  J/T  
Magnetic Field Strength  quantity:MagneticFieldStrength My Note: Did Not Find  L^{1}I^{1}  Ampere Turn per Meter  At/m  
Ampere per meter  A/m  
Magnetic Flux  L^{2}M^{1}T^{2}I^{1}  Weber  Wb  
Magnetic Flux Density  quantity:MagneticFluxDensity My Note: Did Not Find  M^{1}T^{2}I^{1}  Tesla  T  
Magnetomotive Force  U^{1}I^{1}  Ampere Turn  At  
Mass Temperature  M^{1}Θ^{1}  Kilogram kelvin  kgK  
Mass per Time  quantity:MassPerUnitTime My Note: Did Not Find  M^{1}T^{1}  Kilogram per second  kg/s  
Mass per Unit Area  quantity:MassPerUnitArea My Note: Did Not Find  L^{2}M^{1}  Kilogram per square meter  kg/m^2  
Mass per Unit Length  quantity:MassPerUnitLength My Note: Did Not Find  L^{1}M^{1}  Kilogram per meter  kg/m  
Molar Energy  L^{2}M^{1}T^{2}N^{1}  Joule per mole  J/mol  
Molar Heat Capacity  L^{2}M^{1}T^{2}Θ^{1}N^{1}  Joule per mole kelvin  J/(molK)  
Permeability  L^{1}M^{1}T^{2}I^{2}  Henry per meter  H/m  
Permittivity  L^{3}M^{1}T^{4}I^{2}  Farad per meter  F/m  
Plane Angle  U^{1}  Radian  rad  
Power  L^{2}M^{1}T^{3}  Watt  W  
Power per Angle  quantity:PowerPerAngle My Note: Did Not Find  U^{1}L^{2}M^{1}T^{3}  Watt per steradian  W/sr  
Power per Area Angle  U^{1}M^{1}T^{3}  Watt per square meter steradian  W/(m^2sr)  
Power per Unit Area  quantity:PowerPerUnitArea My Note: Did Not Find  M^{1}T^{3}  Watt per square meter  W/m^2  
Pressure or Stress  quantity:PressureOrStress My Note: Did Not Find  L^{1}M^{1}T^{2}  Pascal  Pa  
Resistance  L^{2}M^{1}T^{3}I^{2}  Ohm  Ohm  
Solid Angle  U^{1}  Steradian  sr  
Specific Energy  L^{2}T^{2}  Joule per kilogram  J/kg  
Specific Heat Capacity  L^{2}T^{2}Θ^{1}  Joule per kilogram kelvin  J/(kgK)  
Specific Heat Pressure  L^{3}M^{1}Θ^{1}  Joule per kilogram kelvin per pascal  J/(kmKPa)  
Specific Heat Volume  L^{1}T^{2}Θ^{1}  Joule per kilogram kelvin per cubic meter  J/(kgKm^3)  
Temperature Amount of Substance  Θ^{1}N^{1}  Mole kelvin  molK  
Thermal Conductivity  L^{1}M^{1}T^{3}Θ^{1}  Watt per meter kelvin  W/(m*K)  
Thermal Diffusivity  L^{2}T^{1}  Square meter per second  m^2/sec  
Thermal Insulance  M^{1}T^{3}Θ^{1}  Square meter Kelvin per watt  (K^2)m/W  
Thermal Resistance  L^{2}M^{1}T^{3}Θ^{1}  Kelvin per watt  K/W  
Thermal Resistivity  L^{1}M^{1}T^{3}Θ^{1}  Meter Kelvin per watt  Km/W  
Thrust to Mass Ratio  L^{1}T^{2}  Newton per kilogram  N/kg  
Time Squared  T^{2}  Second time squared  s^2  
Torque  quantity:BendingMomentOrTorque My Note: Did Not Find  L^{2}M^{1}T^{2}  Newton meter  Nm  
Volume  L^{3}  Cubic Meter  m^3  
Volume Thermal Expansion  L^{3}Θ^{1}  Cubic meter per kelvin  m^3/K  
Volume per Unit Time  L^{3}T^{1}  Cubic meter per second  m^3/s  
Volumetric heat capacity  L^{1}M^{1}T^{2}Θ^{1}  Joule per cubic meter kelvin  J/(m^3 K) 
The CGS System
CGS Base and Derived Quantity Kinds and Units
Category  Quantity Kind  QName  Dimension Symbol  Unit  QName  Unit Symbol 
Base  Dimensionless  U  Unity  U  
Length  L  Centimeter  cm  
Mass  M  Gram  g  
Time  T  Second  s  
Derived  Angular Momentum  L^{2}M^{1}T^{1}  Erg second  erg s  
Area  L^{2}  Square centimeter  cm^2  
Dynamic Viscosity  L^{1}M^{1}T^{1}  Poise  P  
Energy Density  L^{1}M^{1}T^{2}  Erg per cubic centimeter  erg/cm^3  
Energy and Work  L^{2}M^{1}T^{2}  Erg  erg  
Force  L^{1}M^{1}T^{2}  Dyne  dyn  
Frequency  T^{1}  Inverse second time  s^1  
Linear Acceleration  L^{1}T^{2}  Centimeter per second squared  cm/s^2  
Linear Velocity  L^{1}T^{1}  Centimeter per second  cm/s  
Power  L^{2}M^{1}T^{3}  Erg per second  erg/s  
Power per Unit Area  quantity:PowerPerUnitArea My Note: Did Not Find  M^{1}T^{3}  Erg per square centimeter second  erg/(cm^2s)  
Pressure or Stress  quantity:PressureOrStress My Note: Did Not Find  L^{1}M^{1}T^{2}  Dyne per square centimeter  dyn/cm^2  
Time Area  quantity:TimeArea My Note: Did Not Find  L^{2}T^{1}  Square centimeter second  cm^2s  
Torque  quantity:BendingMomentOrTorque My Note: Did Not Find  L^{2}M^{1}T^{2}  Dyne centimeter  dyncm  
Volume  L^{3}  Cubic Centimeter  cm^3 
CGS Units for Electricity and Magnetism
There are two different approaches to defining electric and magnetic quantities using the base CGS mechanical quantities of length, mass and time. The Electromagnetic Unit (EMU) approach derives electric charge from Coulomb’s Law, while the Electrostatic Unit (ESU) approach derives electric charge from Ampere’s Law.
EMU Derived Units
Coulomb’s Law states that the force exerted between two charged particles, q_{1} and q_{2}, is inversely proportional to the square of their distance, r.
F=k(q_{1}q_{2})/r^{2}
Retaining only the terms of the quantity kinds involved (force, electric charge, distance), this equation can be rearranged to express electric charge as length multiplied by the square root of force. The CGS Electromagnetic Unit is called the Abcoulomb. The table below contains the dimension symbols and corresponding units of other electricity and magnetism quantity kinds in terms of the base CGS quantity kinds and the definition of electric charge above.
CGS EMU Derived Units for Electricity and Magnetism
Quantity Kind  QName  Dimension Symbol  Unit  QName  Unit Symbol 
Capacitance  L^{1}T^{2}  Abfarad  abF  
Electric Charge  L^{0.5}M^{0.5}  Abcoulomb  abC  
Electric Current  L^{0.5}M^{0.5}T^{1}  Abampere  abA  
Electric Field Strength  quantity:ElectricFieldStrength My Note: Did Not Find  L^{0.5}M^{0.5}T^{2}  Abvolt per Centimeter  abV/cm  
Electric Flux Density  quantity:ElectricFluxDensity My Note: Did Not Find  L^{1.5}M^{0.5}  Abcoulomb per square centimeter  abC/cm^2  
Electrical Conductivity  quantity:ElectricalConductivity My Note: Did Not Find  L^{1}T^{1}  Absiemen  aS  
Electromotive Force  L^{1.5}M^{0.5}T^{2}  Abvolt  abV  
Inductance  L^{1}  Abhenry  abH  
Magnetic Field Strength  quantity:MagneticFieldStrength My Note: Did Not Find  L^{0.5}M^{0.5}T^{1}  Abtesla  abT  
Magnetic Flux  L^{1.5}M^{0.5}T^{1}  Abvolt Second  abVs  
Magnetic Flux Density  quantity:MagneticFluxDensity My Note: Did Not Find  L^{0.5}M^{0.5}T^{1}  Abtesla  abT  
Magnetomotive Force  L^{0.5}M^{0.5}T^{1}  Gilbert  Gi  
Permeability  U^{1}  Relative permeability  μ _{r}  
Permittivity  L^{2}T^{2}  Abfarad per centimeter  abF/cm  
Resistance  L^{1}T^{1}  Abohm  abOhm 
ESU Derived Units
Ampere’s Law of Magnetic Induction states that the force per unit length exerted between two infinite parallel wires at a distince, d, and carrying electric currents I_{1} and I_{2} is proportional to their product divided by the distance between them. I.e.
dF/dl = k(I_{1}I_{2}/d)
Retaining only the terms of the quantity kinds involved (force, electric current, distance), this equation can be rearranged to express electric current as the square root of force. The CGS Electrostatic Unit of electric current is called the Statampere. The table below contains the dimension symbols and corresponding units of other electricity and magnetism quantity kinds in terms of the base CGS quantity kinds and the definition of electric current above.
CGS ESU Derived Units for Electricity and Magnetism
Quantity Kind  QName  Dimension Symbol  Unit  QName  Unit Symbol 
Capacitance  L^{1}  Statfarad  statF  
Electric Charge  L^{1.5}M^{0.5}T^{1}  Statcoulomb  statC  
Electric Current  L^{1.5}M^{0.5}T^{2}  Statampere  statA  
Electric Field Strength  quantity:ElectricFieldStrength My Note: Did Not Find  L^{0.5}M^{0.5}T^{1}  Statvolt per centimeter  statV/cm  
Electric Flux Density  quantity:ElectricFluxDensity My Note: Did Not Find  L^{0.5}M^{0.5}T^{1}  Statcoulomb per square centimeter  statC/cm^2  
Electromotive Force  L^{0.5}M^{0.5}T^{1}  Statvolt  statV  
Inductance  L^{1}T^{2}  Stathenry  statH  
Magnetic Field Strength  quantity:MagneticFieldStrength My Note: Did Not Find  L^{0.5}M^{0.5}T^{2}  Oersted  Oe  
Magnetic Flux  L^{0.5}M^{0.5}  Maxwell  Mx  
Magnetic Flux Density  quantity:MagneticFluxDensity My Note: Did Not Find  L^{1.5}M^{0.5}  Gauss  G  
Magnetomotive Force  L^{1.5}M^{0.5}T^{2}  Oersted centimeter  Oecm  
Permeability  L^{2}T^{2}  Stathenry per centimeter  statH/cm  
Permittivity  U^{1}  Relative permittivity  ε _{r}  
Resistance  L^{1}T^{1}  Statohm  statOhm 
Glossary
 NExIOM
 NASA Exploration Intiatives Ontology Models
 TBD
 To Be Done
 TBR
 To Be Revised
Acknowledgements
[TBR]
 NASA AMES Research Center for sponsoring and content for different engineering disciplines
 TopQuadrant, Inc., for Ontology Architecture, foundation ontologies and tooling support
 European Space Agency (ESA), for constructive dialog and input to the ontology models
References
 The NIST Guide for the use of the International System of Units
 International Vocabulary of Metrology – Basic and General Concepts and Associated Terms
 SI Brochure, 8th Edition
 Dimensional Analysis, Percy Williams Bridgman, Yale University Press (1922)
Last UPDATED August 24, 2013
This work is licensed under a Creative Commons AttributionShare Alike 3.0 United States License.
Instances
Instances of qudt:AtomicPhysicsQuantityKind
Instances of qudt:BiologyQuantityKind
quantity:MicrobialFormation: Microbial Formation
quantity:MicrobialFormation  

Property  Value 
   no properties found 
Instances of qudt:ChemistryQuantityKind
quantity:AmountOfSubstance: Amount of Substance
quantity:AmountOfSubstance  

Property  Value 
qudt:symbol  N 
quantity:AmountOfSubstancePerUnitMass: Amount of Substance per Unit Mass
quantity:AmountOfSubstancePerUnitMass  

Property  Value 
qudt:generalization  quantity:Concentration 
quantity:AmountOfSubstancePerUnitVolume: Amount of Substance Per Unit Volume
quantity:AmountOfSubstancePerUnitVolume  

Property  Value 
qudt:generalization  quantity:Concentration 
quantity:CatalyticActivity: Catalytic Activity
quantity:CatalyticActivity  

Property  Value 
   no properties found 
quantity:ElectricChargePerAmountOfSubstance: Electric Charge per Amount of Substance
quantity:ElectricChargePerAmountOfSubstance  

Property  Value 
   no properties found 
quantity:EnergyAndWorkPerMassAmountOfSubstance: Energy and Work per Mass Amount of Substance
quantity:EnergyAndWorkPerMassAmountOfSubstance  

Property  Value 
   no properties found 
quantity:InverseAmountOfSubstance: Inverse Amount of Substance
quantity:InverseAmountOfSubstance  

Property  Value 
   no properties found 
quantity:LengthMolarEnergy: Length Molar Energy
quantity:LengthMolarEnergy  

Property  Value 
   no properties found 
quantity:MassAmountOfSubstance: Mass Amount of Substance
quantity:MassAmountOfSubstance  

Property  Value 
   no properties found 
quantity:MassAmountOfSubstanceTemperature: Mass Amount of Substance Temperature
quantity:MassAmountOfSubstanceTemperature  

Property  Value 
   no properties found 
quantity:MoleFraction: Mole Fraction
quantity:MoleFraction  

Property  Value 
qudt:description  In chemistry, the mole fraction of a component in a mixture is the relative proportion of molecules belonging to the component to those in the mixture, by number of molecules. It is one way of measuring concentration. 
qudt:generalization  quantity:DimensionlessRatio 
quantity:MolecularMass: Molecular Mass
quantity:MolecularMass  

Property  Value 
qudt:description  The molecular mass, or molecular weight of a chemical compound is the mass of one molecule of that compound, relative to the unified atomic mass unit, u. Molecular mass should not be confused with molar mass, which is the mass of one mole of a substance. 
qudt:generalization  quantity:Mass 
qudt:symbol  M 
quantity:TemperatureAmountOfSubstance: Temperature Amount of Substance
quantity:TemperatureAmountOfSubstance  

Property  Value 
   no properties found 
quantity:Turbidity: Turbidity
quantity:Turbidity  

Property  Value 
qudt:description  Turbidity is the cloudiness or haziness of a fluid, or of air, caused by individual particles (suspended solids) that are generally invisible to the naked eye, similar to smoke in air. Turbidity in open water is often caused by phytoplankton and the measurement of turbidity is a key test of water quality. The higher the turbidity, the higher the risk of the drinkers developing gastrointestinal diseases, especially for immunecompromised people, because contaminants like virus or bacteria can become attached to the suspended solid. The suspended solids interfere with water disinfection with chlorine because the particles act as shields for the virus and bacteria. Similarly suspended solids can protect bacteria from UV sterilisation of water. Fluids can contain suspended solid matter consisting of particles of many different sizes. While some suspended material will be large enough and heavy enough to settle rapidly to the bottom container if a liquid sample is left to stand (the settleable solids), very small particles will settle only very slowly or not at all if the sample is regularly agitated or the particles are colloidal. These small solid particles cause the liquid to appear turbid. 
Instances of qudt:CommunicationsQuantityKind
quantity:RFPower: RFPower
quantity:RFPower  

Property  Value 
qudt:generalization  quantity:SignalStrength 
quantity:SignalDetectionThreshold: Signal Detection Threshold
quantity:SignalDetectionThreshold  

Property  Value 
   no properties found 
quantity:SignalStrength: Signal Strength
quantity:SignalStrength  

Property  Value 
qudt:description  In telecommunications, particularly in radio, signal strength refers to the magnitude of the electric field at a reference point that is a significant distance from the transmitting antenna. It may also be referred to as received signal level or field strength. Typically, it is expressed in voltage per length or signal power received by a reference antenna. Highpowered transmissions, such as those used in broadcasting, are expressed in dBmillivolts per metre (dBmV/m). [Wikipedia] 
qudt:generalization  quantity:ElectricField 
Instances of qudt:ElectricityAndMagnetismQuantityKind
quantity:AuxillaryMagneticField: Auxillary Magnetic Field
quantity:AuxillaryMagneticField  

Property  Value 
qudt:abbreviation  H 
qudt:description  Magnetic Fields surround magnetic materials and electric currents and are detected by the force they exert on other magnetic materials and moving electric charges. The electric and magnetic fields are two interrelated aspects of a single object, called the electromagnetic field. A pure electric field in one reference frame is observed as a combination of both an electric field and a magnetic field in a moving reference frame. The Auxillary Magnetic Field, H characterizes how the true Magnetic Field B influences the organization of magnetic dipoles in a given medium. 
qudt:generalization  quantity:ElectricCurrentPerUnitLength 
quantity:Capacitance: Capacitance
quantity:Capacitance  

Property  Value 
qudt:description  Capacitance is the ability of a body to hold an electrical charge; it is quantified as the amount of electric charge stored for a given electric potential. Capacitance is a scalarvalued quantity. 
quantity:CubicElectricDipoleMomentPerSquareEnergy: Cubic Electric Dipole Moment per Square Energy
quantity:CubicElectricDipoleMomentPerSquareEnergy  

Property  Value 
   no properties found 
quantity:ElectricCharge: Electric Charge
quantity:ElectricCharge  

Property  Value 
qudt:description  Electric charge is a fundamental conserved property of some subatomic particles, which determines their electromagnetic interaction. Electrically charged matter is influenced by, and produces, electromagnetic fields. The electric charge on a body may be positive or negative. Two positively charged bodies experience a mutual repulsive force, as do two negatively charged bodies. A positively charged body and a negatively charged body experience an attractive force. 
qudt:symbol  Q 
quantity:ElectricChargeLineDensity: Electric Charge Line Density
quantity:ElectricChargeLineDensity  

Property  Value 
   no properties found 
quantity:ElectricChargePerAmountOfSubstance: Electric Charge per Amount of Substance
quantity:ElectricChargePerAmountOfSubstance  

Property  Value 
   no properties found 
quantity:ElectricChargePerArea: Electric Charge per Unit Area
quantity:ElectricChargePerArea  

Property  Value 
   no properties found 
quantity:ElectricChargePerMass: Electric Charge per Mass
quantity:ElectricChargePerMass  

Property  Value 
   no properties found 
quantity:ElectricChargeVolumeDensity: Electric Charge Volume Density
quantity:ElectricChargeVolumeDensity  

Property  Value 
qudt:symbol  ? 
quantity:ElectricConductivity: Electric Conductivity
quantity:ElectricConductivity  

Property  Value 
qudt:description  Electric conductivity or specific conductance is a measure of a material's ability to conduct an electric current. When an electrical potential difference is placed across a conductor, its movable charges flow, giving rise to an electric current. The conductivity ? is defined as the ratio of the electric current density J to the electric field E: J = ?E In isotropic materials, conductivity is scalarvalued, however in general, conductivity is a tensorvalued quantity. 
qudt:symbol  ? 
quantity:ElectricCurrent: Electric Current
quantity:ElectricCurrent  

Property  Value 
qudt:description  Electric Current is the flow (movement) of electric charge. The amount of electric current through some surface, e.g., a section through a copper conductor, is defined as the amount of electric charge flowing through that surface over time. Current is a scalarvalued quantity. 
qudt:symbol  I 
quantity:ElectricCurrentDensity: Electric Current Density
quantity:ElectricCurrentDensity  

Property  Value 
qudt:abbreviation  J 
qudt:description  Electric current density is a measure of the density of flow of electric charge; it is the electric current per unit area of cross section. Electric current density is a vectorvalued quantity. 
qudt:symbol  J 
quantity:ElectricCurrentPerAngle: Electric Current per Angle
quantity:ElectricCurrentPerAngle  

Property  Value 
   no properties found 
quantity:ElectricCurrentPerUnitEnergy: Electric Current per Unit Energy
quantity:ElectricCurrentPerUnitEnergy  

Property  Value 
   no properties found 
quantity:ElectricCurrentPerUnitLength: Electric Current per Unit Length
quantity:ElectricCurrentPerUnitLength  

Property  Value 
   no properties found 
quantity:ElectricDipoleMoment: Electric Dipole Moment
quantity:ElectricDipoleMoment  

Property  Value 
qudt:description  The Electric Dipole Moment is a measure of the separation of positive and negative electrical charges in a system of (discrete or continuous) charges. It is a vectorvalued quantity. If the system of charges is neutral, that is if the sum of all charges is zero, then the dipole moment of the system is independent of the choice of a reference frame; however in a nonneutral system, such as the dipole moment of a single proton, a dependence on the choice of reference point arises. In such cases it is conventional to choose the reference point to be the center of mass of the system or the center of charge, not some arbitrary origin. This convention ensures that the dipole moment is an intrinsic property of the system. 
quantity:ElectricDisplacementField: Electric Displacement Field
quantity:ElectricDisplacementField  

Property  Value 
qudt:abbreviation  D 
qudt:description  In a dielectric material the presence of an electric field E causes the bound charges in the material (atomic nuclei and their electrons) to slightly separate, inducing a local electric dipole moment. The Electric Displacement Field, D, is a vector field that accounts for the effects of free charges within such dielectric materials. 
qudt:generalization  quantity:ElectricChargePerArea 
qudt:symbol  D 
quantity:ElectricField: Electric Field
quantity:ElectricField  

Property  Value 
qudt:abbreviation  E 
qudt:description  The space surrounding an electric charge or in the presence of a timevarying magnetic field has a property called an electric field. This electric field exerts a force on other electrically charged objects. In the idealized case, the force exerted between two point charges is inversely proportional to the square of the distance between them. (Coulomb's Law) 
quantity:ElectricFlux: Electric Flux
quantity:ElectricFlux  

Property  Value 
qudt:description  The Electric Flux through an area is defined as the electric field multiplied by the area of the surface projected in a plane perpendicular to the field. Electric Flux is a scalarvalued quantity. 
quantity:ElectricPotential: Electric Potential
quantity:ElectricPotential  

Property  Value 
qudt:description  The Electric Potential is a scalar valued quantity associated with an electric field. The electric potential ?(x) at a point, x, is formally defined as the line integral of the electric field taken along a path from x to the point at infinity. If the electric field is static, i.e. time independent, then the choice of the path is arbitrary; however if the electric field is time dependent, taking the integral along different paths will produce different results. 
qudt:generalization  quantity:EnergyPerElectricCharge 
qudt:symbol  ? 
quantity:ElectricPower: Electric Power
quantity:ElectricPower  

Property  Value 
qudt:description  Electric power is the rate at which electrical energy is transferred by an electric circuit. In the simple case of direct current circuits, electric power can be calculated as the product of the potential difference in the circuit (V) and the amount of current flowing in the circuit (I): P = VI where P is the power V is the potential difference I is the current. However, in general electric power is calculated by taking the integral of the vector crossproduct of the electrical and magnetic fields over a specified area. 
qudt:generalization  quantity:Power 
quantity:ElectricQuadrupoleMoment: Electric Quadrupole Moment
quantity:ElectricQuadrupoleMoment  

Property  Value 
qudt:description  The Electric Quadrupole Moment is a quantity which describes the effective shape of the ellipsoid of nuclear charge distribution. A nonzero quadrupole moment Q indicates that the charge distribution is not spherically symmetric. By convention, the value of Q is taken to be positive if the ellipsoid is prolate and negative if it is oblate. In general, the electric quadrupole moment is tensorvalued. 
qudt:symbol  Q 
quantity:ElectromotiveForce: Electromotive Force
quantity:ElectromotiveForce  

Property  Value 
qudt:description  Electromotive force is the external work expended per unit of charge to produce an electric potential difference across two opencircuited terminals. 
qudt:generalization  quantity:EnergyPerElectricCharge 
qudt:symbol  ? 
quantity:EnergyPerAreaElectricCharge: Energy per Area Electric Charge
quantity:EnergyPerAreaElectricCharge  

Property  Value 
   no properties found 
quantity:EnergyPerElectricCharge: Energy per Electric Charge
quantity:EnergyPerElectricCharge  

Property  Value 
   no properties found 
quantity:EnergyPerSquareMagneticFluxDensity: Energy per Square Magnetic Flux Density
quantity:EnergyPerSquareMagneticFluxDensity  

Property  Value 
   no properties found 
quantity:ForcePerElectricCharge: Force per Electric Charge
quantity:ForcePerElectricCharge  

Property  Value 
   no properties found 
quantity:Inductance: Inductance
quantity:Inductance  

Property  Value 
qudt:description  Inductance is an electromagentic quantity that characterizes a circuit's resistance to any change of electric current; a change in the electric current through induces an opposing electromotive force (EMF). Quantitatively, inductance is proportional to the magnetic flux per unit of electric current. 
qudt:symbol  L 
quantity:InverseMagneticFlux: Inverse Magnetic Flux
quantity:InverseMagneticFlux  

Property  Value 
   no properties found 
quantity:InversePermittivity: Inverse Permittivity
quantity:InversePermittivity  

Property  Value 
   no properties found 
quantity:LengthPerUnitElectricCurrent: Length per Unit Electric Current
quantity:LengthPerUnitElectricCurrent  

Property  Value 
   no properties found 
quantity:LengthPerUnitMagneticFlux: Length per Unit Magnetic Flux
quantity:LengthPerUnitMagneticFlux  

Property  Value 
   no properties found 
quantity:MagneticDipoleMoment: Magnetic Dipole Moment
quantity:MagneticDipoleMoment  

Property  Value 
qudt:description  The magnetic moment of a system is a measure of the magnitude and the direction of its magnetism. Magnetic moment usually refers to its Magnetic Dipole Moment, and quantifies the contribution of the system's internal magnetism to the external dipolar magnetic field produced by the system (that is, the component of the external magnetic field that is inversely proportional to the cube of the distance to the observer). The Magnetic Dipole Moment is a vectorvalued quantity. 
qudt:symbol  ? 
quantity:MagneticField: Magnetic Field
quantity:MagneticField  

Property  Value 
qudt:abbreviation  B 
qudt:description  The Magnetic Field, denoted B, is a fundamental field in electrodynamics which characterizes the magnetic force exerted by electric currents. It is closely related to the auxillary magnetic field H (see quantity:AuxillaryMagneticField). 
qudt:symbol  B 
quantity:MagneticFlux: Magnetic Flux
quantity:MagneticFlux  

Property  Value 
qudt:description  Magnetic Flux is the product of the average magnetic field times the perpendicular area that it penetrates. 
qudt:symbol  ? 
quantity:MagneticFluxPerUnitLength: Magnetic Flux per Unit Length
quantity:MagneticFluxPerUnitLength  

Property  Value 
   no properties found 
quantity:MagnetizationField: Magnetization Field
quantity:MagnetizationField  

Property  Value 
qudt:abbreviation  M 
qudt:description  The Magnetization Field is defined as the ratio of magnetic moment per unit volume. It is a vectorvalued quantity. 
qudt:generalization  quantity:ElectricCurrentPerUnitLength 
qudt:symbol  M 
quantity:MagnetomotiveForce: Magnetomotive Force
quantity:MagnetomotiveForce  

Property  Value 
qudt:description  Magnetomotive Force (mmf) is the ability of an electric circuit to produce magnetic flux. Just as the ability of a battery to produce electric current is called its electromotive force or emf, mmf is taken as the work required to move a unit magnet pole from any point through any path which links the electric circuit back the same point in the presence of the magnetic force produced by the electric current in the circuit. 
quantity:MassPerElectricCharge: Mass per Electric Charge
quantity:MassPerElectricCharge  

Property  Value 
   no properties found 
quantity:Permeability: Permeability
quantity:Permeability  

Property  Value 
qudt:description  Permeability is the degree of magnetization of a material that responds linearly to an applied magnetic field. In general permeability is a tensorvalued quantity. 
qudt:symbol  ? 
quantity:Permittivity: Permittivity
quantity:Permittivity  

Property  Value 
qudt:description  Permittivity is a physical quantity that describes how an electric field affects, and is affected by a dielectric medium, and is determined by the ability of a material to polarize in response to the field, and thereby reduce the total electric field inside the material. Permittivity is often a scalar valued quantity, however in the general case it is tensorvalued. 
qudt:symbol  ? 
quantity:Polarizability: Polarizability
quantity:Polarizability  

Property  Value 
qudt:description  Polarizability is the relative tendency of a charge distribution, like the electron cloud of an atom or molecule, to be distorted from its normal shape by an external electric field, which may be caused by the presence of a nearby ion or dipole. The electronic polarizability ? is defined as the ratio of the induced dipole moment of an atom to the electric field that produces this dipole moment. Polarizability is often a scalar valued quantity, however in the general case it is tensorvalued. 
qudt:symbol  ? 
quantity:PolarizationField: Polarization Field
quantity:PolarizationField  

Property  Value 
qudt:description  The Polarization Field is the vector field that expresses the density of permanent or induced electric dipole moments in a dielectric material. The polarization vector P is defined as the ratio of electric dipole moment per unit volume. 
qudt:generalization  quantity:ElectricChargePerArea 
qudt:symbol  P 
quantity:PowerPerElectricCharge: Power per Electric Charge
quantity:PowerPerElectricCharge  

Property  Value 
   no properties found 
quantity:QuarticElectricDipoleMomentPerCubicEnergy: Quartic Electric Dipole Moment per Cubic Energy
quantity:QuarticElectricDipoleMomentPerCubicEnergy  

Property  Value 
   no properties found 
quantity:Resistance: Resistance
quantity:Resistance  

Property  Value 
qudt:description  The electrical resistance of an object is a measure of its opposition to the passage of a steady electric current. 
qudt:symbol  R 
Instances of qudt:FinancialQuantityKind
quantity:Asset: Asset
quantity:Asset  

Property  Value 
qudt:description  An Asset is an economic resource owned by a business or company. Simply stated, assets are things of value that can be readily converted into cash (although cash itself is also considered an asset). 
Instances of qudt:FluidMechanicsQuantityKind
quantity:AtmosphericPressure: Atmospheric Pressure
quantity:AtmosphericPressure  

Property  Value 
qudt:description  The pressure exerted at a point due to the presence of an atmosphere. In most circumstances atmospheric pressure is closely approximated by the hydrostatic pressure caused by the weight of air above the measurement point. Low pressure areas have less atmospheric mass above their location, whereas high pressure areas have more atmospheric mass above their location. Similarly, as elevation increases there is less overlying atmospheric mass, so that pressure decreases with increasing elevation. [Wikipedia] 
qudt:generalization  quantity:Pressure 
quantity:Circulation: Circulation
quantity:Circulation  

Property  Value 
qudt:description  In fluid dynamics, circulation is the line integral around a closed curve of the fluid velocity. It has dimensions of length squared over time. 
qudt:generalization  quantity:AreaPerTime 
qudt:symbol  ? 
quantity:DynamicPressure: Dynamic Pressure
quantity:DynamicPressure  

Property  Value 
qudt:description  Dynamic Pressure (indicated with q, or Q, and sometimes called velocity pressure) is the quantity defined by: q = 1/2 * ?v^2 where (using SI units): q = dynamic pressure in pascals ? = fluid density in kg/m3 (e.g. density of air) v = fluid velocity in m/s 
qudt:generalization  quantity:Pressure 
qudt:symbol  q 
quantity:DynamicViscosity: Dynamic Viscosity
quantity:DynamicViscosity  

Property  Value 
qudt:generalization  quantity:Viscosity 
qudt:symbol  ? 
quantity:KinematicViscosity: Kinematic Viscosity
quantity:KinematicViscosity  

Property  Value 
qudt:abbreviation  The Kinematic Viscosity of a fluid is the dynamic viscosity divided by the fluid density. 
qudt:generalization  quantity:AreaPerTime 
quantity:MolecularViscosity: Molecular Viscosity
quantity:MolecularViscosity  

Property  Value 
qudt:generalization  quantity:Viscosity 
quantity:Pressure: Pressure
quantity:Pressure  

Property  Value 
qudt:description  Pressure is an effect which occurs when a force is applied on a surface. Pressure is the amount of force acting on a unit area. Pressure is distinct from stress, as the former is the ratio of the component of force normal to a surface to the surface area. Stress is a tensor that relates the vector force to the vector area. 
qudt:generalization  quantity:ForcePerArea 
quantity:ReynoldsNumber: Reynolds Number
quantity:ReynoldsNumber  

Property  Value 
qudt:description  The Reynolds number (Re) is a dimensionless number defined as the ratio of inertial forces to viscous forces and, consequently, it quantifies the relative importance of these two types of forces for given flow conditions. 
qudt:generalization  quantity:DimensionlessRatio 
quantity:StaticPressure: Static Pressure
quantity:StaticPressure  

Property  Value 
qudt:description  Static Pressure is the pressure at a nominated point in a fluid. Every point in a steadily flowing fluid, regardless of the fluid speed at that point, has its own static pressure P, dynamic pressure q, and total pressure P_0. The total pressure is the sum of the dynamic and static pressures, i.e. P_0 = P + q. 
qudt:generalization  quantity:Pressure 
quantity:TotalPressure: Total Pressure
The total pressure is the sum of the dynamic and static pressures, i.e. P_0 = P + q.
quantity:TotalPressure  

Property  Value 
qudt:description  The total pressure is the sum of the dynamic and static pressures, i.e. P_0 = P + q. 
qudt:generalization  quantity:Pressure 
qudt:symbol  P_0 
quantity:Viscosity: Viscosity
quantity:Viscosity  

Property  Value 
qudt:description  Viscosity is a measure of the resistance of a fluid which is being deformed by either shear stress or extensional stress. In general terms it is the resistance of a liquid to flow, or its "thickness". Viscosity describes a fluid's internal resistance to flow and may be thought of as a measure of fluid friction. [Wikipedia] 
quantity:Vorticity: Vorticity
quantity:Vorticity  

Property  Value 
qudt:description  In the simplest sense, vorticity is the tendency for elements of a fluid to "spin." More formally, vorticity can be related to the amount of "circulation" or "rotation" (or more strictly, the local angular rate of rotation) in a fluid. The average vorticity in a small region of fluid flow is equal to the circulation C around the boundary of the small region, divided by the area A of the small region. Mathematically, vorticity is a vector field and is defined as the curl of the velocity field. 
qudt:generalization  quantity:AngularVelocity 
qudt:symbol  ? 
Instances of qudt:InformationQuantityKind
quantity:Capacity: Capacity
quantity:Capacity  

Property  Value 
qudt:description  In computer operations, (a) the largest quantity which can be stored, processed, or transferred; (b) the largest number of digits or characters which may regularly be processed; (c) the upper and lower limits of the quantities which may be processed. In other contexts, the amount of material that can be stored, such as fuel or food. 
qudt:symbol  TBD 
quantity:DataRate: Data Rate
quantity:DataRate  

Property  Value 
qudt:description  The frequency derived from the period of time required to transmit one bit. This represents the amount of data transferred per second by a communications channel or a computing or storage device. Data rate is measured in units of bits per second (written "b/s" or "bps"), bytes per second (Bps), or baud. When applied to data rate, the multiplier prefixes "kilo", "mega", "giga", etc. (and their abbreviations, "k", "M", "G", etc.) always denote powers of 1000. For example, 64 kbps is 64,000 bits per second. This contrasts with units of storage which use different prefixes to denote multiplication by powers of 1024, e.g. 1 kibibit = 1024 bits. 
Instances of qudt:MechanicsQuantityKind
quantity:AngularMomentum: Angular Momentum
quantity:AngularMomentum  

Property  Value 
qudt:description  Quantity of rotational motion. Linear momentum is the quantity obtained by multiplying the mass of a body by its linear velocity. Angular momentum is the quantity obtained by multiplying the moment of inertia of a body by its angular velocity. The momentum of a system of particles is given by the sum of the momenta of the individual particles which make up the system or by the product of the total mass of the system and the velocity of the center of gravity of the system. The momentum of a continuous medium is given by the integral of the velocity over the mass of the medium or by the product of the total mass of the medium and the velocity of the center of gravity of the medium. In physics, the angular momentum of an object rotating about some reference point is the measure of the extent to which the object will continue to rotate about that point unless acted upon by an external torque. In particular, if a point mass rotates about an axis, then the angular momentum with respect to a point on the axis is related to the mass of the object, the velocity and the distance of the mass to the axis. While the motion associated with linear momentum has no absolute frame of reference, the rotation associated with angular momentum is sometimes spoken of as being measured relative to the fixed stars. 
qudt:generalization  quantity:Momentum 
quantity:EnergyAndWork: Energy and Work
quantity:EnergyAndWork  

Property  Value 
   no properties found 
quantity:EnergyDensity: Energy Density
quantity:EnergyDensity  

Property  Value 
qudt:description  Energy density is defined as energy per unit volume. The SI unit for energy density is the joule per cubic meter. 
quantity:EnergyInternal: Internal Energy
quantity:EnergyInternal  

Property  Value 
qudt:generalization  quantity:EnergyAndWork 
quantity:EnergyKinetic: Kinetic Energy
quantity:EnergyKinetic  

Property  Value 
qudt:generalization  quantity:EnergyAndWork 
quantity:EnergyPerArea: Energy per Area
quantity:EnergyPerArea  

Property  Value 
   no properties found 
quantity:Force: Force
quantity:Force  

Property  Value 
qudt:description  Force is an influence that causes mass to accelerate. It may be experienced as a lift, a push, or a pull. Force is defined by Newton's Second Law as F = m · a, where F is force, m is mass and a is acceleration. Net force is mathematically equal to the time rate of change of the momentum of the body on which it acts. Since momentum is a vector quantity (has both a magnitude and direction), force also is a vector quantity. 
quantity:ForceMagnitude: Force Magnitude
quantity:ForceMagnitude  

Property  Value 
   no properties found 
quantity:ForcePerAreaTime: Force Per Area Time
quantity:ForcePerAreaTime  

Property  Value 
   no properties found 
quantity:ForcePerLength: Force per Unit Length
quantity:ForcePerLength  

Property  Value 
   no properties found 
quantity:Friction: Friction
quantity:Friction  

Property  Value 
qudt:description  Friction is the force of two surfaces In contact, or the force of a medium acting on a moving object (i.e. air on an aircraft). When contacting surfaces move relative to each other, the friction between the two objects converts kinetic energy into thermal energy. 
qudt:generalization  quantity:Force 
quantity:GravitationalAttraction: Gravitational Attraction
quantity:GravitationalAttraction  

Property  Value 
   no properties found 
quantity:InverseEnergy: Inverse Energy
quantity:InverseEnergy  

Property  Value 
   no properties found 
quantity:InverseSquareEnergy: Inverse Square Energy
quantity:InverseSquareEnergy  

Property  Value 
   no properties found 
quantity:KineticEnergy: Kinetic Energy
quantity:KineticEnergy  

Property  Value 
qudt:description  The energy which a body possesses as a consequence of its motion, defined as onehalf the product of its mass m and the square of its speed v, 1/2 mv^2. The kinetic energy per unit volume of a fluid parcel is the 1/2 p v2 , where p is the density and v the speed of the parcel. See potential energy. For relativistic speeds the kinetic energy is given by Ek = mc^2  m0c^2 where c is the velocity of light in a vacuum, m0 is the rest mass, and m is the moving mass. 
qudt:generalization  quantity:EnergyAndWork 
quantity:LinearMomentum: Linear Momentum
quantity:LinearMomentum  

Property  Value 
qudt:description  Linear momentum is the product of mass and linear velocity. The SI unit for linear momentum is meterkilogram per second (mkg/s). 
qudt:generalization  quantity:Momentum 
quantity:MassPerAreaTime: Mass per Area Time
quantity:MassPerAreaTime  

Property  Value 
   no properties found 
quantity:MassPerLength: Mass per Length
quantity:MassPerLength  

Property  Value 
   no properties found 
quantity:MolarAngularMomentum: Molar Angular Momentum
quantity:MolarAngularMomentum  

Property  Value 
   no properties found 
quantity:MomentOfInertia: Moment of Inertia
quantity:MomentOfInertia  

Property  Value 
   no properties found 
quantity:Momentum: Momentum
quantity:Momentum  

Property  Value 
qudt:description  Quantity of motion. Linear momentum is the quantity obtained by multiplying the mass of a body by its linear speed. Angular momentum is the quantity obtained by multiplying the moment of inertia of a body by its angular speed. The momentum of a system of particles is given by the sum of the momentums of the individual particles which make up the system or by the product of the total mass of the system and the velocity of the center of gravity of the system. The momentum of a continuous medium is given by the integral of the velocity over the mass of the medium or by the product of the total mass of the medium and the velocity of the center of gravity of the medium. 
quantity:PolarMomentOfInertia: Polar moment of inertia
quantity:PolarMomentOfInertia  

Property  Value 
qudt:description  The polar moment of inertia is a quantity used to predict an object's ability to resist torsion, in objects (or segments of objects) with an invariant circular crosssection and no significant warping or outofplane deformation. It is used to calculate the angular displacement of an object subjected to a torque. It is analogous to the area moment of inertia, which characterizes an object's ability to resist bending. 
quantity:PotentialEnergy: Potential Energy
quantity:PotentialEnergy  

Property  Value 
qudt:description  Energy possessed by a body by virtue of its position in a gravity field in contrast with kinetic energy, that possessed by virtue of its motion. 
qudt:generalization  quantity:EnergyAndWork 
quantity:Power: Power
quantity:Power  

Property  Value 
qudt:description  Power is the rate at which work is performed or energy is transmitted, or the amount of energy required or expended for a given unit of time. As a rate of change of work done or the energy of a subsystem, power is: P = W/t where P is power W is work t is time. [Wikipedia] 
quantity:PowerAreaPerSolidAngle: Power Area per Solid Angle
quantity:PowerAreaPerSolidAngle  

Property  Value 
   no properties found 
quantity:PowerPerAreaAngle: Power per Area Angle
quantity:PowerPerAreaAngle  

Property  Value 
   no properties found 
quantity:SpecificEnergy: Specific Energy
quantity:SpecificEnergy  

Property  Value 
   no properties found 
quantity:SpecificImpulseByMass: Specific Impulse by Mass
quantity:SpecificImpulseByMass  

Property  Value 
qudt:generalization  quantity:LinearVelocity 
quantity:SpecificImpulseByWeight: Specific Impulse by Weight
quantity:SpecificImpulseByWeight  

Property  Value 
qudt:generalization  quantity:Time 
quantity:SpecificVolume: Specific Volume
quantity:SpecificVolume  

Property  Value 
qudt:abbreviation  ? 
qudt:description  Specific volume (?) is the volume occupied by a unit of mass of a material. It is equal to the inverse of density. 
qudt:symbol  ? 
quantity:StandardGravitationalParameter: Standard Gravitational Parameter
quantity:StandardGravitationalParameter  

Property  Value 
qudt:symbol  ? 
quantity:Thrust: Thrust
quantity:Thrust  

Property  Value 
qudt:description  Thrust is a reaction force described quantitatively by Newton's Second and Third Laws. When a system expels or accelerates mass in one direction the accelerated mass will cause a proportional but opposite force on that system. 1. The pushing or pulling force developed by an aircraft engine or a rocket engine. 2. The force exerted in any direction by a fluid jet or by a powered screw, as, the thrust of an antitorque rotor. 3. (symbol F). Specifically, in rocketry, F = mv where m is propellant mass flow and v is exhaust velocity relative to the vehicle. Also called momentum thrust. 
qudt:generalization  quantity:Force 
quantity:ThrustToMassRatio: Thrust to Mass Ratio
quantity:ThrustToMassRatio  

Property  Value 
   no properties found 
quantity:Torque: Torque
quantity:Torque  

Property  Value 
qudt:description  In physics, a torque (?) is a vector that measures the tendency of a force to rotate an object about some axis [1]. The magnitude of a torque is defined as force times its lever arm [2]. Just as a force is a push or a pull, a torque can be thought of as a twist. The SI unit for torque is newton meters (N m). In U.S. customary units, it is measured in foot pounds (ft lbf) (also known as 'pounds feet'). Mathematically, the torque on a particle (which has the position r in some reference frame) can be defined as the cross product: ? = r x F where r is the particle's position vector relative to the fulcrum F is the force acting on the particles, or, more generally, torque can be defined as the rate of change of angular momentum, ? = dL/dt where L is the angular momentum vector t stands for time. [Wikipedia] 
quantity:Weight: Weight
quantity:Weight  

Property  Value 
qudt:description  1. The force with which a body is attracted toward an astronomical body. 2. The product of the mass of a body and the acceleration acting on a body. In a dynamic situation, the weight can be a multiple of that under resting conditions. Weight also varies on other planets in accordance with their gravity. 
Instances of qudt:PhotometryQuantityKind
quantity:Illuminance: Illuminance
quantity:Illuminance  

Property  Value 
qudt:description  Illuminance is the total luminous flux incident on a surface, per unit area. It is a measure of the intensity of the incident light, wavelengthweighted by the luminosity function to correlate with human brightness perception. 
qudt:generalization  quantity:LuminousFluxPerArea 
quantity:Luminance: Luminance
quantity:Luminance  

Property  Value 
qudt:description  Luminance is a photometric measure of the luminous intensity per unit area of light travelling in a given direction. It describes the amount of light that passes through or is emitted from a particular area, and falls within a given solid angle. 
quantity:LuminousEfficacy: Luminous Efficacy
quantity:LuminousEfficacy  

Property  Value 
qudt:description  Luminous Efficacy is the ratio of luminous flux (in lumens) to power (usually measured in watts). Depending on context, the power can be either the radiant flux of the source's output, or it can be the total electric power consumed by the source. 
quantity:LuminousEmmitance: Luminous Emmitance
Luminous Emittance is the luminous flux per unit area emitted from a surface.
quantity:LuminousEmmitance  

Property  Value 
qudt:description  Luminous Emittance is the luminous flux per unit area emitted from a surface. 
qudt:generalization  quantity:LuminousFluxPerArea 
quantity:LuminousEnergy: Luminous Energy
quantity:LuminousEnergy  

Property  Value 
qudt:description  Luminous Energy is the perceived energy of light. This is sometimes also called the quantity of light. 
qudt:symbol  Qv 
quantity:LuminousFlux: Luminous Flux
quantity:LuminousFlux  

Property  Value 
qudt:description  Luminous Flux or Luminous Power is the measure of the perceived power of light. It differs from radiant flux, the measure of the total power of light emitted, in that luminous flux is adjusted to reflect the varying sensitivity of the human eye to different wavelengths of light. 
qudt:symbol  F 
quantity:LuminousFluxPerArea: Luminous Flux per Area
quantity:LuminousFluxPerArea  

Property  Value 
   no properties found 
quantity:LuminousIntensity: Luminous Intensity
quantity:LuminousIntensity  

Property  Value 
qudt:description  Luminous Intensity is a measure of the wavelengthweighted power emitted by a light source in a particular direction per unit solid angle. The weighting is determined by the luminosity function, a standardized model of the sensitivity of the human eye to different wavelengths. 
qudt:symbol  J 
Instances of qudt:QuantityKind
quantity:AbsoluteHumidity: Absolute Humidity
quantity:AbsoluteHumidity  

Property  Value 
qudt:description  Absolute humidity is the mass of water in a particular volume of air. It is a measure of the density of water vapor in an atmosphere. 
qudt:generalization  quantity:Density 
quantity:DimensionlessRatio: Dimensionless Ratio
quantity:DimensionlessRatio  

Property  Value 
qudt:generalization  quantity:Dimensionless 
qudt:symbol  ? 
quantity:Gain: Gain
quantity:Gain  

Property  Value 
qudt:description  A general term used to denote an increase in signal power or signal strength in transmission from one point to another. Gain is usually expressed in decibels and is widely used to denote transducer gain. An increase or amplification. In radar there are two general usages of the term: (a) antenna gain, or gain factor, is the ratio of the power transmitted along the beam axis to that of an isotropic radiator transmitting the same total power; (b) receiver gain, or video gain, is the amplification given a signal by the receiver. 
qudt:generalization  quantity:DimensionlessRatio 
Instances of qudt:QuantumMechanicsQuantityKind
quantity:Activity: Activity
quantity:Activity  

Property  Value 
qudt:description  Activity is the term used to characterise the number of nuclei which disintegrate in a radioactive substance per unit time. Activity is usually measured in Becquerels (Bq), where 1 Bq is 1 disintegration per second. 
qudt:generalization  quantity:StochasticProcess 
Instances of qudt:RadiologyQuantityKind
quantity:AbsorbedDose: Absorbed Dose
quantity:AbsorbedDose  

Property  Value 
qudt:description  Absorbed dose (also known as Total Ionizing Dose, TID) is a measure of the energy deposited in a medium by ionizing radiation. It is equal to the energy deposited per unit mass of medium, and so has the unit J/kg, which is given the special name Gray (Gy). Note that the absorbed dose is not a good indicator of the likely biological effect. 1 Gy of alpha radiation would be much more biologically damaging than 1 Gy of photon radiation for example. Appropriate weighting factors can be applied reflecting the different relative biological effects to find the equivalent dose. The risk of stoctic effects due to radiation exposure can be quantified using the effective dose, which is a weighted average of the equivalent dose to each organ depending upon its radiosensitivity. When ionising radiation is used to treat cancer, the doctor will usually prescribe the radiotherapy treatment in Gy. When risk from ionising radiation is being discussed, a related unit, the Sievert is used. 
qudt:generalization  quantity:SpecificEnergy 
quantity:AbsorbedDoseRate: Absorbed Dose Rate
quantity:AbsorbedDoseRate  

Property  Value 
   no properties found 
quantity:DoseEquivalent: Dose Equivalent
quantity:DoseEquivalent  

Property  Value 
qudt:description  The equivalent dose to a tissue is found by multiplying the absorbed dose, in gray, by a dimensionless "quality factor" Q, dependent upon radiation type, and by another dimensionless factor N, dependent on all other pertinent factors. N depends upon the part of the body irradiated, the time and volume over which the dose was spread, even the species of the subject. 
qudt:generalization  quantity:SpecificEnergy 
Instances of qudt:RadiometryQuantityKind
quantity:Irradiance: Irradiance
quantity:Irradiance  

Property  Value 
qudt:description  Irradiance and Radiant Emittance are radiometry terms for the power per unit area of electromagnetic radiation at a surface. "Irradiance" is used when the electromagnetic radiation is incident on the surface. "Radiant emmitance" (or "radiant exitance") is used when the radiation is emerging from the surface. 
qudt:generalization  quantity:PowerPerArea 
quantity:Radiance: Radiance
quantity:Radiance  

Property  Value 
qudt:description  Radiance is a radiometric measure that describes the amount of light that passes through or is emitted from a particular area, and falls within a given solid angle in a specified direction. 
qudt:generalization  quantity:PowerPerAreaAngle 
quantity:RadiantEmmitance: Radiant Emmitance
quantity:RadiantEmmitance  

Property  Value 
qudt:description  Irradiance and Radiant Emittance are radiometry terms for the power per unit area of electromagnetic radiation at a surface. "Irradiance" is used when the electromagnetic radiation is incident on the surface. "Radiant emmitance" (or "radiant exitance") is used when the radiation is emerging from the surface. 
qudt:generalization  quantity:PowerPerArea 
quantity:RadiantEnergy: Radiant Energy
quantity:RadiantEnergy  

Property  Value 
qudt:description  Radiant Energy is the energy of electromagnetic waves. The quantity of radiant energy may be calculated by integrating radiant flux (or power) with respect to time 
qudt:generalization  quantity:EnergyAndWork 
quantity:RadiantFlux: Radiant Flux
quantity:RadiantFlux  

Property  Value 
qudt:description  Radiant Flux, or radiant power, is the measure of the total power of electromagnetic radiation (including infrared, ultraviolet, and visible light). The power may be the total emitted from a source, or the total landing on a particular surface. 
qudt:generalization  quantity:Power 
qudt:symbol  ? 
quantity:RadiantIntensity: Radiant Intensity
quantity:RadiantIntensity  

Property  Value 
qudt:description  Radiant Intensity is a measure of the intensity of electromagnetic radiation. It is defined as power per unit solid angle. 
quantity:Radiosity: Radiosity
Radiosity is the total emitted and reflected radiation leaving a surface.
quantity:Radiosity  

Property  Value 
qudt:description  Radiosity is the total emitted and reflected radiation leaving a surface. 
qudt:generalization  quantity:PowerPerArea 
quantity:FirstMomentOfArea: First Moment of Area
quantity:FirstMomentOfArea  

Property  Value 
qudt:description  The first moment of area is the summation of area times distance to an axis. It is a measure of the distribution of the area of a shape in relationship to an axis. 
qudt:generalization  quantity:Volume 
quantity:SecondMomentOfArea: Second Moment of Area
quantity:SecondMomentOfArea  

Property  Value 
qudt:description  The second moment of area is a property of a physical object that can be used to predict its resistance to bending and deflection. The deflection of an object under load depends not only on the load, but also on the geometry of the object's crosssection. 
quantity:Strain: Strain
quantity:Strain  

Property  Value 
qudt:description  In any branch of science dealing with materials and their behaviour, strain is the geometrical expression of deformation caused by the action of stress on a physical body. Strain is calculated by first assuming a change between two body states: the beginning state and the final state. Then the difference in placement of two points in this body in those two states expresses the numerical value of strain. Strain therefore expresses itself as a change in size and/or shape. [Wikipedia] 
qudt:generalization  quantity:Dimensionless 
quantity:StrainEnergyDensity: Strain Energy Density
quantity:StrainEnergyDensity  

Property  Value 
qudt:generalization  quantity:EnergyDensity 
qudt:symbol  u 
quantity:Stress: Stress
quantity:Stress  

Property  Value 
qudt:description  Stress is a measure of the average amount of force exerted per unit area of a surface within a deformable body on which internal forces act. In other words, it is a measure of the intensity or internal distribution of the total internal forces acting within a deformable body across imaginary surfaces. These internal forces are produced between the particles in the body as a reaction to external forces applied on the body. 
qudt:generalization  quantity:ForcePerArea 
quantity:Tension: Tension
quantity:Tension  

Property  Value 
qudt:description  Tension is the magnitude of the pulling force exerted by a string, cable, chain, or similar object on another object. It is the opposite of compression. 
qudt:generalization  quantity:ForceMagnitude 
Instances of qudt:SpaceAndTimeQuantityKind
quantity:Acceleration: Acceleration
quantity:Acceleration  

Property  Value 
qudt:description  Acceleration is the (instantaneous) rate of change of velocity. Acceleration may be either linear acceleration, or angular acceleration. It is a vector quantity with dimension length/time^2 for linear acceleration, or in the case of angular acceleration, with dimension angle/time^2. In SI units, linear acceleration is measured in meters/second^2 (m·s^2) and angular acceleration is measured in radians/second^2. In common speech, the term acceleration is only used for an increase in speed. In physics, any increase or decrease in speed is referred to as acceleration and similarly, motion in a circle at constant speed is also an acceleration, since the direction component of the velocity is changing. 
quantity:Angle: Angle
quantity:Angle  

Property  Value 
qudt:description  The inclination to each other of two intersecting lines, measured by the arc of a circle intercepted between the two lines forming the angle, the center of the circle being the point of intersection. An acute angle is less than 90°; a right angle 90 °; an obtuse angle, more than 90° but less than 180 °; a straight angle, 180°; a reflex angle, more than 180° but less than 360°; a perigon, 360°. Any angle not a multiple of 90° is an oblique angle. If the sum of two angles is 90°, they are complementary angles; if 180°, supplementary angles; if 360°, explementary angles. Two adjacent angles have a common vertex and lie on opposite sides of a common side. A dihedral angle is the angle between two intersecting planes. A spherical angle is the angle between two intersecting great circles. 
qudt:generalization  quantity:DimensionlessRatio 
quantity:AngularAcceleration: Angular Acceleration
quantity:AngularAcceleration  

Property  Value 
qudt:description  Angular acceleration is the rate of change of angular velocity over time. Measurement of the change made in the rate of change of an angle that a spinning object undergoes per unit time. It is a vector quantity. Also called Rotational acceleration. In SI units, it is measured in radians per second squared (rad/s^2), and is usually denoted by the Greek letter alpha. 
qudt:generalization  quantity:Acceleration 
quantity:AngularFrequency: Angular Frequency
quantity:AngularFrequency  

Property  Value 
qudt:description  Angular frequency is a scalar measure of rotation rate. It is the magnitude of the vector quantity angular velocity. 
qudt:generalization  quantity:Frequency 
qudt:symbol  ? 
quantity:AngularVelocity: Angular Velocity
quantity:AngularVelocity  

Property  Value 
qudt:description  The change of angle per unit time; specifically, in celestial mechanics, the change in angle of the radius vector per unit time. 
qudt:generalization  quantity:Velocity 
quantity:Area: Area
quantity:Area  

Property  Value 
qudt:description  Area is a quantity expressing the twodimensional size of a defined part of a surface, typically a region bounded by a closed curve. 
quantity:Curvature: Curvature
quantity:Curvature  

Property  Value 
qudt:description  The canonical example of extrinsic curvature is that of a circle, which has curvature equal to the inverse of its radius everywhere. Smaller circles bend more sharply, and hence have higher curvature. The curvature of a smooth curve is defined as the curvature of its osculating circle at each point. The osculating circle of a sufficiently smooth plane curve at a given point on the curve is the circle whose center lies on the inner normal line and whose curvature is the same as that of the given curve at that point. This circle is tangent to the curve at the given point. That is, given a point P on a smooth curve C, the curvature of C at P is defined to be 1/R where R is the radius of the osculating circle of C at P. The magnitude of curvature at points on physical curves can be measured in diopters (also spelled dioptre) — this is the convention in optics. [Wikipedia] 
quantity:DryVolume: Dry Volume
quantity:DryVolume  

Property  Value 
qudt:generalization  quantity:Volume 
quantity:Frequency: Frequency
quantity:Frequency  

Property  Value 
qudt:description  Frequency is the number of occurrences of a repeatiing event per unit time. The repetition of the events may be periodic (i.e. the length of time between event repetitions is fixed) or aperiodic (i.e. the length of time between event repetitions varies). Therefore, we distinguish between periodic and aperiodic frequencies. In the SI system, periodic frequency is measured in hertz (Hz) or multiples of hertz, while aperiodic frequency is measured in becquerel (Bq). 
quantity:InverseLength: Inverse Length
quantity:InverseLength  

Property  Value 
   no properties found 
quantity:InverseVolume: Inverse Volume
quantity:InverseVolume  

Property  Value 
   no properties found 
quantity:LinearAcceleration: Linear Acceleration
quantity:LinearAcceleration  

Property  Value 
qudt:generalization  quantity:Acceleration 
quantity:LinearVelocity: Linear Velocity
quantity:LinearVelocity  

Property  Value 
qudt:generalization  quantity:Velocity 
quantity:LiquidVolume: Liquid Volume
quantity:LiquidVolume  

Property  Value 
qudt:generalization  quantity:Volume 
quantity:MachNumber: Mach Number
quantity:MachNumber  

Property  Value 
qudt:description  Mach number (Ma) is the speed of an object moving through air, or any fluid substance, divided by the speed of sound as it is in that substance: M = V_o/V_s where M is the Mach number V_o is the velocity of the object relative to the medium and V_s is the velocity of sound in the medium The Mach number is commonly used both with objects traveling at high speed in a fluid, and with highspeed fluid flows inside channels such as nozzles, diffusers or wind tunnels. As it is defined as a ratio of two speeds, it is a dimensionless number. [Wikipedia] 
qudt:generalization  quantity:DimensionlessRatio 
quantity:NumberDensity: Number Density
quantity:NumberDensity  

Property  Value 
qudt:description  In physics, astronomy, and chemistry, number density (symbol: n) is a kind of quantity used to describe the degree of concentration of countable objects (atoms, molecules, dust particles, galaxies, etc.) in the threedimensional physical space. 
qudt:generalization  quantity:InverseVolume 
qudt:symbol  n 
quantity:PlaneAngle: Plane Angle
quantity:PlaneAngle  

Property  Value 
qudt:generalization  quantity:Angle 
quantity:SolidAngle: Solid Angle
quantity:SolidAngle  

Property  Value 
qudt:description  The solid angle subtended by a surface S is defined as the surface area of a unit sphere covered by the surface S's projection onto the sphere. A solid angle is related to the surface of a sphere in the same way an ordinary angle is related to the circumference of a circle. Since the total surface area of the unit sphere is 4*pi, the measure of solid angle will always be between 0 and 4*pi. 
qudt:generalization  quantity:Angle 
quantity:Speed: Speed
Speed is the magnitude of velocity.
quantity:Speed  

Property  Value 
qudt:description  Speed is the magnitude of velocity. 
quantity:StochasticProcess: Stochastic Process
quantity:StochasticProcess  

Property  Value 
qudt:generalization  quantity:Frequency 
quantity:Time: Time
quantity:Time  

Property  Value 
qudt:description  Time is a basic component of the measuring system used to sequence events, to compare the durations of events and the intervals between them, and to quantify the motions of objects. 
qudt:symbol  T 
quantity:Volume: Volume
quantity:Volume  

Property  Value 
qudt:description  The volume of a solid object is the threedimensional concept of how much space it occupies, often quantified numerically. Onedimensional figures (such as lines) and twodimensional shapes (such as squares) are assigned zero volume in the threedimensional space. 
Instances of qudt:SystemOfQuantities
quantity:SystemOfQuantities_CGS: CGS System of Quantities
quantity:SystemOfQuantities_CGSEMU: CGSEMU System of Quantities
quantity:SystemOfQuantities_CGSESU: CGSESU System of Quantities
quantity:SystemOfQuantities_CGSGauss: CGSGauss System of Quantities
quantity:SystemOfQuantities_Planck: Planck System of Quantities
quantity:SystemOfQuantities_SI: International System of Quantities
quantity:SystemOfQuantities_USCustomary: US Customary System of Quantities
Instances of qudt:ThermodynamicsQuantityKind
quantity:AreaTemperature: Area Temperature
quantity:AreaTemperature  

Property  Value 
   no properties found 
quantity:AreaThermalExpansion: Area Thermal Expansion
quantity:AreaThermalExpansion  

Property  Value 
qudt:description  When the temperature of a substance changes, the energy that is stored in the intermolecular bonds between atoms changes. When the stored energy increases, so does the length of the molecular bonds. As a result, solids typically expand in response to heating and contract on cooling; this dimensional response to temperature change is expressed by its coefficient of thermal expansion. Different coefficients of thermal expansion can be defined for a substance depending on whether the expansion is measured by: * linear thermal expansion * area thermal expansion * volumetric thermal expansion These characteristics are closely related. The volumetric thermal expansion coefficient can be defined for both liquids and solids. The linear thermal expansion can only be defined for solids, and is common in engineering applications. Some substances expand when cooled, such as freezing water, so they have negative thermal expansion coefficients. [Wikipedia] 
quantity:AreaTimeTemperature: Area Time Temperature
quantity:AreaTimeTemperature  

Property  Value 
   no properties found 
quantity:CoefficientOfHeatTransfer: Coefficient of Heat Transfer
quantity:CoefficientOfHeatTransfer  

Property  Value 
   no properties found 
quantity:CompressibilityFactor: Compressibility Factor
quantity:CompressibilityFactor  

Property  Value 
qudt:description  The compressibility factor (Z) is a useful thermodynamic property for modifying the ideal gas law to account for the real gas behaviour. The closer a gas is to a phase change, the larger the deviations from ideal behavior. Values for compressibility are calculated using equations of state (EOS), such as the virial equation and van der Waals equation. The compressibility factor for specific gases can be obtained, with out calculation, from compressibility charts. These charts are created by plotting Z as a function of pressure at constant temperature. 
qudt:generalization  quantity:DimensionlessRatio 
qudt:symbol  Z 
quantity:EnergyPerTemperature: Energy per Temperature
quantity:EnergyPerTemperature  

Property  Value 
   no properties found 
quantity:Enthalpy: Enthalpy
quantity:Enthalpy  

Property  Value 
qudt:description  Static enthalpy per unit mass. The specific enthalpy of a working mass is a property of that mass used in thermodynamics, defined as h=u+p . v where u is the specific internal energy, p is the pressure, and v is specific volume. In other words, h = H / m where m is the mass of the system. The SI unit for specific enthalpy is joules per kilogram. [Wikipedia] 
qudt:generalization  quantity:EnergyAndWork 
quantity:Heat: Heat
quantity:Heat  

Property  Value 
qudt:description  Energy transferred by a thermal process. Heat can be measured in terms of the dynamical units of energy, as the erg, joule, etc., or in terms of the amount of energy required to produce a definite thermal change in some substance, as, for example, the energy required per degree to raise the temperature of a unit mass of water at some temperature ( calorie, Btu). 
qudt:generalization  quantity:ThermalEnergy 
quantity:HeatCapacity: Heat Capacity
quantity:HeatCapacity  

Property  Value 
qudt:generalization  quantity:EnergyPerTemperature 
qudt:symbol  Cp 
quantity:HeatCapacityRatio: Heat Capacity Ratio
quantity:HeatCapacityRatio  

Property  Value 
qudt:description  The heat capacity ratio, or ratio of specific heats, is the ratio of the heat capacity at constant pressure (C_P) to heat capacity at constant volume (C_V). For an ideal gas, the heat capacity is constant with temperature (?). Accordingly we can express the enthalpy as H = C_P*? and the internal energy as U = C_V*?. Thus, it can also be said that the heat capacity ratio is the ratio between enthalpy and internal energy 
qudt:generalization  quantity:DimensionlessRatio 
quantity:HeatFlowRate: Heat Flow Rate
quantity:HeatFlowRate  

Property  Value 
qudt:generalization  quantity:Power 
quantity:HeatFlowRatePerUnitArea: Heat Flow Rate per Unit Area
quantity:HeatFlowRatePerUnitArea  

Property  Value 
qudt:generalization  quantity:PowerPerArea 
quantity:InverseLengthTemperature: Inverse Length Temperature
quantity:InverseLengthTemperature  

Property  Value 
   no properties found 
quantity:InverseTimeTemperature: Inverse Time Temperature
quantity:InverseTimeTemperature  

Property  Value 
   no properties found 
quantity:LengthTemperature: Length Temperature
quantity:LengthTemperature  

Property  Value 
   no properties found 
quantity:LengthTemperatureTime: Length Temperature Time
quantity:LengthTemperatureTime  

Property  Value 
   no properties found 
quantity:LinearThermalExpansion: Linear Thermal Expansion
quantity:LinearThermalExpansion  

Property  Value 
qudt:description  When the temperature of a substance changes, the energy that is stored in the intermolecular bonds between atoms changes. When the stored energy increases, so does the length of the molecular bonds. As a result, solids typically expand in response to heating and contract on cooling; this dimensional response to temperature change is expressed by its coefficient of thermal expansion. Different coefficients of thermal expansion can be defined for a substance depending on whether the expansion is measured by: * linear thermal expansion * area thermal expansion * volumetric thermal expansion These characteristics are closely related. The volumetric thermal expansion coefficient can be defined for both liquids and solids. The linear thermal expansion can only be defined for solids, and is common in engineering applications. Some substances expand when cooled, such as freezing water, so they have negative thermal expansion coefficients. [Wikipedia] 
quantity:MassTemperature: Mass Temperature
quantity:MassTemperature  

Property  Value 
   no properties found 
quantity:MolarHeatCapacity: Molar Heat Capacity
quantity:MolarHeatCapacity  

Property  Value 
   no properties found 
quantity:PowerPerAreaQuarticTemperature: Power per Area Quartic Temperature
quantity:PowerPerAreaQuarticTemperature  

Property  Value 
   no properties found 
quantity:SpecificHeatCapacity: Specific Heat Capacity
quantity:SpecificHeatCapacity  

Property  Value 
   no properties found 
quantity:SpecificHeatPressure: Specific Heat Pressure
Specific heat at a constant pressure.
quantity:SpecificHeatPressure  

Property  Value 
qudt:description  Specific heat at a constant pressure. 
quantity:SpecificHeatVolume: Specific Heat Volume
Specific heat per constant volume.
quantity:SpecificHeatVolume  

Property  Value 
qudt:description  Specific heat per constant volume. 
quantity:TemperaturePerMagneticFluxDensity: Temperature per Magnetic Flux Density
quantity:TemperaturePerMagneticFluxDensity  

Property  Value 
   no properties found 
quantity:TemperaturePerTime: Temperature per Time
quantity:TemperaturePerTime  

Property  Value 
   no properties found 
quantity:ThermalConductivity: Thermal Conductivity
quantity:ThermalConductivity  

Property  Value 
   no properties found 
quantity:ThermalDiffusivity: Thermal Diffusivity
quantity:ThermalDiffusivity  

Property  Value 
qudt:generalization  quantity:AreaPerTime 
quantity:ThermalEfficiency: Thermal Efficiency
quantity:ThermalEfficiency  

Property  Value 
qudt:description  Thermal efficiency is a dimensionless performance measure of a thermal device such as an internal combustion engine, a boiler, or a furnace. The input to the device is heat, or the heatcontent of a fuel that is consumed. The desired output is mechanical work, or heat, or possibly both. 
qudt:generalization  quantity:DimensionlessRatio 
quantity:ThermalEnergy: Thermal Energy
quantity:ThermalEnergy  

Property  Value 
qudt:generalization  quantity:EnergyAndWork 
quantity:ThermalEnergyLength: Thermal Energy Length
quantity:ThermalEnergyLength  

Property  Value 
   no properties found 
quantity:ThermalInsulance: Thermal Insulance
quantity:ThermalInsulance  

Property  Value 
   no properties found 
quantity:ThermalResistance: Thermal Resistance
quantity:ThermalResistance  

Property  Value 
   no properties found 
quantity:ThermalResistivity: Thermal Resistivity
quantity:ThermalResistivity  

Property  Value 
qudt:description  The reciprocal of thermal conductivity is thermal resistivity, measured in kelvinmetres per watt (K*m/W). 
quantity:ThermodynamicEntropy: Thermodynamic Entropy
quantity:ThermodynamicEntropy  

Property  Value 
qudt:description  Thermodynamic Entropy is a measure of the unavailability of a system’s energy to do work. It is a measure of the randomness of molecules in a system and is central to the second law of thermodynamics and the fundamental thermodynamic relation, which deal with physical processes and whether they occur spontaneously. Spontaneous changes, in isolated systems, occur with an increase in entropy. Spontaneous changes tend to smooth out differences in temperature, pressure, density, and chemical potential that may exist in a system, and entropy is thus a measure of how far this smoothingout process has progressed. It can be seen that the dimensions of entropy are energy divided by temperature, which is the same as the dimensions of Boltzmann's constant (kB) and heat capacity. The SI unit of entropy is joule per kelvin. [Wikipedia] 
qudt:generalization  quantity:EnergyPerTemperature 
quantity:ThermodynamicTemperature: Temperature
quantity:ThermodynamicTemperature  

Property  Value 
qudt:symbol  ? 
quantity:TimeTemperature: Time Temperature
quantity:TimeTemperature  

Property  Value 
   no properties found 
quantity:VolumeThermalExpansion: Volume Thermal Expansion
quantity:VolumeThermalExpansion  

Property  Value 
qudt:description  When the temperature of a substance changes, the energy that is stored in the intermolecular bonds between atoms changes. When the stored energy increases, so does the length of the molecular bonds. As a result, solids typically expand in response to heating and contract on cooling; this dimensional response to temperature change is expressed by its coefficient of thermal expansion. Different coefficients of thermal expansion can be defined for a substance depending on whether the expansion is measured by: * linear thermal expansion * area thermal expansion * volumetric thermal expansion These characteristics are closely related. The volumetric thermal expansion coefficient can be defined for both liquids and solids. The linear thermal expansion can only be defined for solids, and is common in engineering applications. Some substances expand when cooled, such as freezing water, so they have negative thermal expansion coefficients. [Wikipedia] 
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