Calculations

Growth rate calculation

Here we can calculate the growth rate of the new phase in an interface-controlled phase transformation, which is based on the equation (Turbull,  1956):

v = ko T exp[(ΔHa+PVa)/RT][1-exp⁡((ΔGr)/RT)]

where v is the growth rate, ΔHa is activation enthalpy, Va is the activation volume, ΔGr is the free energy of the reaction, R is the gas constant and ko is a constant.

Example values of different parameters for incoherent interface-controlled growth in olivine-ringwoodite transformation (Mosenfelder et al., 2001; Ohtani et al., 2004; Miyahara et al., 2010)

 ΔH= 404000 (J/mol)

Va = 0 (m3/mol)

ΔGr = -20353 (J/mol)

R  =  8.314 (J/K mol)

ko = 45479 (m/s K)

To get the value of the growth rate at different temperatures in a tabular form, use the calculator given below. Put the values of Start and End temperatures of your interest and the calculator will give you the tabular values of growth rates at temperatures with increments of 10 K from the Start value. For example, if the Start and End values are 1000 K and 1050 K, then the growth rate will be calculated for 1000, 1010, 1020, 1030, 1040, and 1050 K.

The 1D Transient Heat Conduction Calculator is a tool that helps calculate the temperature distribution in a rod over time. It does this by solving the 1D transient heat conduction equation using the finite difference method.

The 1D transient heat conduction equation is a partial differential equation that describes the change in temperature of a rod over time due to heat conduction. It is given by:

∂T/∂t = α∂^2T/∂x^2 + Q

Where T is the temperature, t is time, x is position, α is the thermal diffusivity, and Q is the heat generation per unit volume.

The finite difference method is a numerical technique for solving differential equations by approximating them with a set of algebraic equations. In this case, the 1D transient heat conduction equation is discretized in space and time, and the resulting system of algebraic equations is solved using an iterative method such as the Jacobi or Gauss-Seidel method.

The calculator takes several input parameters, including the length and diameter of the rod, the density and heat capacity of the material, the thermal conductivity, the heat generation, the time step, the initial temperature, and the boundary temperature. It then calculates the temperature distribution at successive time steps and displays the results using a chart.