added ethanol:water (50:50) mixture

data/functions.py

@@ -108,6 +108,24 @@ Vmcg = df_desc['VMcGowan']
 m = ~pd.isna(Vabc)
 popt_V = np.polyfit(Vmcg[m], Vabc[m], 1)
 
+# ---- model: Grunberg–Nissan style with polynomial interaction that vanishes at x=0,1 ----
+# fitted to data from R. Belda, J. V. Herráez, O. Diez, Rheological study and thermodynamic analysis of the binary system (water/ethanol): Influence of concentration. Physics and Chemistry of Liquids 42, 467-479 (2004).
+popt_etoh = np.array([-6.35036532e+00, 1.86507282e+03, -5.30902320e+00, 1.60463200e+03, -1.03040657e+01, 3.05646061e+00, -4.93824317e+00, 4.16274239e+03, -1.18411097e+03, 1.69557649e+03])
+def predict_lneta(p, T, x, n_poly=3, interaction_has_T=True):
+    Aw, Bw, Ae, Be = p[:4]  # ln(eta_w)=Aw+Bw/T, ln(eta_e)=Ae+Be/T
+    ln_eta_w = Aw + Bw / T
+    ln_eta_e = Ae + Be / T
+    xc = 2.0*x - 1.0  # map wt frac [0,1] -> [-1,1]
+    Phi = np.vstack([xc**k for k in range(n_poly)])  # (n_poly, N)
+    if interaction_has_T:
+        a = p[4:4+n_poly]
+        b = p[4+n_poly:4+2*n_poly]
+        G = (a @ Phi) + (b @ Phi) / T
+    else:
+        a = p[4:4+n_poly]
+        G = (a @ Phi)
+    return x*ln_eta_e + (1-x)*ln_eta_w + x*(1-x)*G
+
 def get_WC(T,solv,V):
     params = df_visc[df_visc['Solvent_Name']==solv].iloc[0]
     if params['Equation'] == '10^A(1/T-1/B)':
@@ -126,6 +144,9 @@ def get_WC(T,solv,V):
         eta = params['A'] * 298.15/T
     elif params['Equation'] == 'A*T+B':
         eta = params['A'] * T + params['A']
+    elif params['Equation'] == 'fitted_EtOH':
+        # assuming 50% is by volume --> by mass for consistency with fitted model
+        eta = np.exp(predict_lneta(popt_etoh, T, 0.5*0.7898/(0.5*0.7898+0.5*1.000), n_poly=3, interaction_has_T=True))
     else:
         eta = np.nan
     D_WC = 7.4e-8*(params['MW']*params['WC_assoc_param'])**0.5*(T)/eta/V**0.6

data/solventData.xlsx

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:6e8423a4b7eac365ace7d8ce2bfb3ab83506f356ce86453c80d5654bfe957a44
-size 15758
+oid sha256:8786e15998c9272e69ad5bc20d096cfbb0044e6af49e7947aa8d4740aec663d3
+size 15835