In Ecolego it is not necessary to specify units for each object. This entry is optional. However, the user should specify the unit of the simulation time step and materials (if materials are included in the model) before starting a simulation. The default unit for the simulation time step is Year but can be changed in the simulation settings window.

Units are specified in the properties page when editing blocks. Some objects like compartments and transfers cannot be assigned units because they are implicit from the materials and time unit of the model. For instance, if the unit for the material “Arsenic” is set to “kg” and the simulation time unit is set to “year”, the unit of a compartment will be (kg) and the unit of a transfer will be (kg/year).

Use ^ to enter exponents, for example: m^2 s^-1 will be displayed as (m² s^-1)

To specify unit notations such as “freshweight” or “particle” you can use a ”.”. For example: kg.fw will be displayed as (kg_fw).

The unit suffix is important for unit checking, see below.

There is no automatic unit conversion in Ecolego. You can however convert units when you enter parameter values by using the constants editing tool. The units supported are listed below.

By default Ecolego will not perform unit checking. To enable this feature, open the errors and warnings page of the preferences screen.

The unit checking algorithm is strict - there might be cases (for instance with empirical relationships) where the unit checker will report an error even if there is none. Also, when using suffixes, the unit checking algorithm will refuse to accept mixing of quantities. For instance, the expression rho(kg/m³) = m (kg_part)/V(m³) will fail because kg != kg_part.

The default unit for radionuclides is mol. The unit must be the same for all radionuclides, so when the unit is changed from mol to Bq for one radionuclide the unit of all other radionuclides will change.

Time Mass Length s Second kg Kilogram m Meter min Minute 60 s u Atomic mass 10^-3/
6.02214199 10²³ kg ft Foot 0.3048 m h Hour 60 min me Electron mass 9.10938188 10^-31 kg yd Yard 3 ft d Day 24 h lb Pound 0.45359237 kg in Inch 1/12 ft week Week 7 d oz_av Ounce 1/16 lb Å Angstrom 10^-10 m month Month 1/7 year ton_UK Long ton 2240 lb ua Astronomical unit 149597870691.0 m year Year 31556952 s t Metric ton 1000 kg ly Light year 9.460528405 10¹⁵ m Plane angle Area Volume rad Radian m² Square meter m² m³ Cubic meter m³ rev Revolution 2π rad a Are 100 m² L Liter 0.001 m³ ° Degree angle 1/360 rev ha Hectar 100 a gallon_liquid_US Gallon liquid US 231 in³ ' Minute angle 1/60 ° b Barn 10^-28 m² pint_liquid_US Pint liquid US 1/8 gallon_liquid_US '' Second angle 1/60 ' Velocity fluid_ounce_US Fluid ounce US 1/16 pint_liquid_US grade Grade 1/400 rev m/s Meter per second m/s gallon_dry_US Gallon dry US 268.8025 in³ Solid angle M Mach 331.6 m/s pint_dry_US Pint dry US 1/8 gallon_dry_US sr Steradian Acceleration gallon_UK Gallon UK 4.54609 L sphere Sphere 4π sr m/s² Meters per second square m/s² pint_UK Pint UK 1/8 gallon_UK Temperature Pressure Substance K Kelvin Pa Pascal N m^-2 mol Mole C Celsius K+273.15 atm Atmosphere 101325 Pa atom Atom 1/6.02214199 10²³ mol °R Rankine 5/9 K bar Bar 100 kPa Frequency °F Farenheit 459.67 °R mm_Hg Millimeter of mercury 133.322 Pa Hz Hertz s^-1 Force Energy Magnetic flux N Newton kg s^-2 J Joule N m Wb Weber V s dyn Dyne 10^-5 N Btu British thermal unit 1055.056 J Mx Maxwell 10^-8 Wb kgf Kilogram force 9.80665 N Btu_Th British thermal unit (thermochemical) 1054.350 J Magnetic flux density lbf Pound force 9.80665 N kb Btu_mean British thermal unit (mean) 1055.87 J T Tesla W m^-2 Power cal Calorie 4.1868 J G Gauss 10^-4 T W Watt J/s Cal Kilocalorie 10³ cal Inductance hp Horsepower 735.499 W erg Erg 10^-7 J H Henry W/A eV Electron-volt 1.602176462 10^-19 J Electric current Electric charge Electric resistance A Ampere C Coulomb s A Ω Ohm V/A Gi Gilbert 10/4π A e Electron 1.602176462 10^-19 C Electric conductance Electromotive force Fd Faraday 1.602176462 10^-19 3.3356 10^-10 C F Farad C/V V Volt W/A Fr Franklin 3.3356 10^-10 6.02214199 10²³C Capacitance S Siemens A/V Luminous intensity Lumenous flux Illuminance cd Candela lm Lumen cd sr lx Lux lm m^-2 La Lambert 10 ⁴ lx Activity Absorbed dose Dose equivalent Bq Bequerel s^-1 Gy Gray J/kg Sv Sievert J/kg Ci Curie 3.7 10¹⁰ Bq rd Rad 0.01 Gy rem Rem 0.01 Sv Rd Rutherford 10⁶ Bq Catalytic activity Ionizing ability kat Katal R Röntgen C/kg

• Expression syntax