+ zmedi2=mod(zmedi,boxzsize)
+ if (zmedi2.lt.0) zmedi2=zmedi2+boxzsize
+ if ((zmedi2.gt.bordlipbot)
+ &.and.(zmedi2.lt.bordliptop)) then
+C the energy transfer exist
+ if (zmedi2.lt.buflipbot) then
+C what fraction I am in
+ fracinbuf=1.0d0-
+ & ((zmedi2-bordlipbot)/lipbufthick)
+C lipbufthick is thickenes of lipid buffore
+ sslipi=sscalelip(fracinbuf)
+ ssgradlipi=-sscagradlip(fracinbuf)/lipbufthick
+ elseif (zmedi2.gt.bufliptop) then
+ fracinbuf=1.0d0-((bordliptop-zmedi2)/lipbufthick)
+ sslipi=sscalelip(fracinbuf)
+ ssgradlipi=sscagradlip(fracinbuf)/lipbufthick
+ else
+ sslipi=1.0d0
+ ssgradlipi=0.0d0
+ endif
+ else
+ sslipi=0.0d0
+ ssgradlipi=0.0d0
+ endif
+