Page 393 - Handbook Of Multiphase Flow Assurance

392 10. Research methods in flow assurance

nii= nbackbone
endif
endif
C outer loop over polymer segments
DO j = ni , nii
Es(j)=0.d0
nhbcount=0
do jj=1,monocount(j)
natom1 = monodata(j,jj)
Ener=0.D0
C ...inner loop over water molecules
DO 200 Iw = 1, Nwatrs
C ... loop over all atoms on each water molecule
DO 200 I = 1, 3
Ehb = 0.D0
Elj = 0.D0
Xi = xw(Iw,I)
Yi = yw(Iw,I)
Zi = zw(Iw,I)
Qi = qw(I)
C
Xij = Xi - xn(natom1)
Yij = Yi - yn(natom1)
Zij = Zi - zn(natom1)
C
C ... minimum image distances in x & y to keep surface under chain
if (ap.eq.1.or.ap.eq.3) then
C we are dealing with the [100] or [110] hydrate surface-rectangular box
IF (Yij .GT. ymaxh) Yij = Yij - ymax
IF (Yij .LT.-ymaxh) Yij = Yij + ymax
IF (Xij .GT. xmaxh) Xij = Xij - xmax
IF (Xij .LT.-xmaxh) Xij = Xij + xmax
endif

if(ap.eq.2) then
C We are using [111] surface - rhombic boundaries
if (Yij .GT. ymaxh) then
Yij = Yij - ymax
Xij = Xij - xmaxh
endif
if (Yij .LT.-ymaxh) then
Yij = Yij + ymax
Xij = Xij + xmaxh
endif
IF (Xij .GT. xmaxh) Xij = Xij - xmax