The Term Tab provides definitions of mathematical expressions that are used as intermediate terms in the expressions for the chemical reaction/equilibrium model. The Expression Builder button in the Term tab can be used to build mathematical expression of all the terms. A mathematical expression is comprised of terms, species (species concentrations), parameters, constants, keywords, and mathematical functions and operators.

FieldDescription
TermTerm ID is the identifying name given to the term.
ExpressionThe Expression is a mathematical expression involving species, parameters, constants, hydraulic variables or other terms.
DescriptionDescription of the meaning or usage of the expression term.

The keywords include: D (Pipe diameter), Re (Renolds number), Kc (Pipe roughness coefficient), Q (Pipe flow or tank net outlet flow), U (Flow velocity), Us (Pipe shear velocity), Ff (DarcyWeisbach friction factor), Av (Surface Area/Unit volume), and Le (Tank water level)
Mathematical functions and operators include:

OperatorFunction Description
-Subtract
Multiply
/  Divide
Exponent
(  Open parenthesis
)Close parenthesis
EXP(X)Returns the Exponential of a value in parenthesis.
STEP(X)STEP function is evaluated to 1 when x > 0 and is 0 otherwise.
SIN(X)Returns the Sine of the value in parenthesis.
COS(X)Returns the Cosine of the value in parenthesis.
TAN(X)

Returns the Tangent of the value in parenthesis.

COT(X)Returns the Cotangent of the value in parenthesis.
SGN(X)Returns the Sign of the value in parenthesis (1 if positive or zero and -1 if negative).
ABS(X) Returns the Absolute Value of the value in parenthesis.
ASIN(X) Returns the Arcsine of the value in parenthesis.
ACOS(X)Returns the Arccosine of the value in parenthesis.
ATAN(X)Returns the Arctangent of the value in parenthesis.
ACOT(X)Returns the Arc cotangent of the value in parenthesis.
SINH(X)Returns the Hyperbolic Sine of the value in parenthesis.
COSH(X)Returns the Hyperbolic Cosine of the value in parenthesis.
TANH(X) Returns the Hyperbolic Tangent of the value in parenthesis.
COTH(X) Returns the Hyperbolic Cotangent of the value in parenthesis.
LOG10(X) Returns the Base-10 Logarithm of the value in parenthesis Log 10.
CURVE (Curve_ID, X_ID, interpolation method)Where CURVE_ID is the ID of the curve, X_ID is the ID of the X value for the curve and interpolation method is either LINEAR or STEPWISE.