#initiation of variable
from math import pi
Hf=-1.16*10**9 # Latent heat of fusion in J/m^3
Y=0.132 # Surface energy in J/m^2
Tm=1064+273.0 # Melting point of gold in K
T=1064+273-230.0 # 230 is supercoiling value in K
a=0.413*10**-9 # Unit Cell edge length in m
n = 4.0 # Number of atoms in a FCC unit cell
#part A
#calculation
r=-2*Y*Tm/(Hf*(Tm-T));
G=16*pi*Y**3*Tm**2/(3*Hf**2*(Tm-T)**2);
#result
print" Critical Radius is : %.2f nm" %(r/10**-9);
print" Activation free energy is : %.2e J" %G
print "Answer in book is 9.64e-19 J. It is due to approximation at intermediate stage"
#part B
u_c=4*pi*r**3/(3*a**3)
tot_uc = n*int(u_c) # Total no. of atoms per critical nucleus
#result
print" Unit cells per paricle are : %d" %u_c;
print" Total no. of atoms per critical nucleus are : %d" %tot_uc;
#initiation of variable
#part A
t1=10
print " At 350C the isothermic reaction begins time",t1, "s and reaches completion of about 500s completion time"
#partB
t2=150
print " In this case it takes about time",t2,"s for the reaction to begin and so, at 100s the specimen is 100% austenite"
#partC
t3=7
print "In this case reaction begins after time",t3,"s and at about 20s 50% of reaction is complete"