diff --git a/Cantera/python/Cantera/liquidvapor.py b/Cantera/python/Cantera/liquidvapor.py
new file mode 100644
index 000000000..c5337ecaa
--- /dev/null
+++ b/Cantera/python/Cantera/liquidvapor.py
@@ -0,0 +1,18 @@
+"""Fluids with complete liquid/vapor equations of state."""
+
+from importFromFile import importPhase
+
+def Water():
+    return importPhase('liquidvapor.cti','water')
+
+def Nitrogen():
+    return importPhase('liquidvapor.cti','nitrogen')
+
+def Methane():
+    return importPhase('liquidvapor.cti','methane')
+
+def Hydrogen():
+    return importPhase('liquidvapor.cti','hydrogen')
+
+def Oxygen():
+    return importPhase('liquidvapor.cti','oxygen')
diff --git a/Cantera/python/Cantera/pureFluids.py b/Cantera/python/Cantera/pureFluids.py
deleted file mode 100644
index f768ca398..000000000
--- a/Cantera/python/Cantera/pureFluids.py
+++ /dev/null
@@ -1,16 +0,0 @@
-from importFromFile import importPhase
-
-def Water():
-    return importPhase('purefluids.cti','water')
-
-def Nitrogen():
-    return importPhase('purefluids.cti','nitrogen')
-
-def Methane():
-    return importPhase('purefluids.cti','methane')
-
-def Hydrogen():
-    return importPhase('purefluids.cti','hydrogen')
-
-def Oxygen():
-    return importPhase('purefluids.cti','oxygen')
diff --git a/Cantera/python/Cantera/set.py b/Cantera/python/Cantera/set.py
index acf64c10a..baaa82e62 100755
--- a/Cantera/python/Cantera/set.py
+++ b/Cantera/python/Cantera/set.py
@@ -1,58 +1,98 @@
 from exceptions import CanteraError
 
 def setByName(a, options):
-    
+
+    tval = None
     pval = None
     hval = None
     uval = None
     sval = None
     vval = None
+    qval = None
+    
     np = 0
+    nt = 0
+    nv = 0
+    nx = 0
+    ny = 0
+    ns = 0
+    nh = 0
+    nu = 0
+    nq = 0
     
     for o in options.keys():
         val = options[o]
         if o == 'Temperature' or o == 'T':
-            a.setTemperature(val)
+            nt += 1
+            tval = val
         elif o == 'Density' or o == 'Rho':
-            a.setDensity(val)
+            nv += 1
             vval = 1.0/val
-        elif o == 'V':
-            a.setDensity(1.0/val)
+        elif o == 'Volume' or o == 'V':
+            nv += 1
             vval = val
         elif o == 'MoleFractions' or o == 'X':
+            nx += 1
             a.setMoleFractions(val)
         elif o == 'MassFractions' or o == 'Y':
+            ny += 1
             a.setMassFractions(val)            
         elif o == 'Pressure' or o == 'P':
             pval = val
-            np = np + 1
+            np += 1
         elif o == 'Enthalpy' or o == 'H':
             hval = val
-            np = np + 1
+            nh += 1
         elif o == 'IntEnergy' or o == 'U':
             uval = val
-            np = np + 1             
+            nu += 1             
         elif o == 'Entropy' or o == 'S':
             sval = val
-            np = np + 1
+            ns += 1
+        elif o == 'Sat' or o == 'Vapor' or o == 'Vap':
+            nq += 1
+            qval = val
+            
         else:
             raise CanteraError('unknown property: '+o)
 
-    if np == 1:
-        if pval:
-            a.setPressure(pval)
+    if nx + ny > 1:
+        raise CanteraError('composition specified multiple times')
 
-    if np >= 2: 
-        if pval and hval:
-            a.setState_HP(hval,pval)
-        elif uval and vval:
-            a.setState_UV(uval,vval)
-        elif sval and pval:
-            a.setState_SP(sval,pval)   
-        elif sval and vval:
-            a.setState_SV(sval,vval)      
+    ntot = nt + np + nv + ns + nh + nu + nq
+
+    if ntot == 1:
+        if nt == 1:
+            a.setTemperature(tval)
+        elif nv == 1:
+            a.setDensity(1.0/vval)
+        elif np == 1:
+            a.seetPressure(pval)
+        else:
+            props = options.keys()
+            raise CanteraError('property '+props[0]+
+                               ' can only be set in combination with '
+                               +'another property')
+    elif ntot == 2:
+        if np == 1 and nh == 1:
+            a.setState_HP(hval, pval)
+        elif nu == 1 and nv == 1:
+            a.setState_UV(uval, vval)
+        elif ns == 1 and np == 1:
+            a.setState_SP(sval, pval)
+        elif ns == 1 and nv == 1:
+            a.setState_SV(sval, vval)
+        elif nt == 1 and np == 1:
+            a.setState_TP(tval, pval)
+        elif nt == 1 and nv == 1:
+            a.setState_TR(tval, 1.0/vval)
+        elif nt == 1 and nq == 1:
+            a.setState_Tsat(tval, qval)
+        elif np == 1 and nq == 1:
+            a.setState_Psat(pval, qval)
         else:
             raise CanteraError('unimplemented property pair')
+
    
 def set(a, **options):
     setByName(a, options)
diff --git a/Cantera/python/examples/rankine.py b/Cantera/python/examples/rankine.py
index c5be77b5f..e4095eec8 100644
--- a/Cantera/python/examples/rankine.py
+++ b/Cantera/python/examples/rankine.py
@@ -1,14 +1,21 @@
 #
-# an Rankine cycle
+# A Rankine vapor power cycle
 #
+
 from Cantera import *
 from Cantera.liquidvapor import Water
 
+
+########################################################
+#
 # parameters
+#
+
 eta_pump = 0.6     # pump isentropic efficiency
-et_turbine = 0.8   # turbine isentropic efficiency
+eta_turbine = 0.8  # turbine isentropic efficiency
 pmax = 8.0e5       # maximum pressure
 
+
 ########################################################
 #
 # some useful functions
@@ -19,27 +26,33 @@ def pump(fluid, pfinal, eta):
     a pump with isentropic efficiency eta."""
     h0 = fluid.enthalpy_mass()
     s0 = fluid.entropy_mass()
-    fluid.setState_SP(s0, pfinal)
+    fluid.set(S = s0, P = pfinal)
     h1s = fluid.enthalpy_mass()
     isentropic_work = h1s - h0
     actual_work = isentropic_work / eta
     h1 = h0 + actual_work
-    fluid.setState_HP(h1, pfinal)
+    fluid.set(H = h1, P = pfinal)
     return actual_work
 
+
 def expand(fluid, pfinal, eta):
     """Adiabatically expand a fluid to pressure pfinal, using
     a turbine with isentropic efficiency eta."""
     h0 = fluid.enthalpy_mass()
     s0 = fluid.entropy_mass()
-    fluid.setState_SP(s0, pfinal)
+    fluid.set(S = s0, P = pfinal)
     h1s = fluid.enthalpy_mass()
     isentropic_work = h0 - h1s
     actual_work = isentropic_work * eta
     h1 = h0 - actual_work
-    fluid.setState_HP(h1, pfinal)
+    fluid.set(H = h1, P = pfinal)
     return actual_work
 
+
+def printState(n, fluid):
+    print '\n\n***************** State '+`n`+' ******************\n', fluid
+    
+
 ###############################################################
 
 
@@ -47,37 +60,35 @@ def expand(fluid, pfinal, eta):
 w = Water()
 
 # start with saturated liquid water at 300 K
-w.setTemperature(300.0)
-w.setState_Tsat(0.0)
-hf = w.enthalpy_mass()
-print w
-w.setState_Tsat(1.0)
-hv = w.enthalpy_mass()
-print hv - hf
-
-print w
+w.set(T = 300.0, Vapor = 0.0)
+h1 = w.enthalpy_mass()
+p1 = w.pressure()
+printState(1,w)
 
 # pump it adiabatically to pmax
 pump_work = pump(w, pmax, eta_pump)
-print pump_work
+h2 = w.enthalpy_mass()
+printState(2,w)
 
 # heat it at constant pressure until it reaches the
 # saturated vapor state at this pressure
-#w.setState_Psat(1.0)
-#print w
+w.set(P = pmax, Vapor = 1.0)
+h3 = w.enthalpy_mass()
+heat_added = h3 - h2
+printState(3,w)
+
+# expand back to p1
+turbine_work = expand(w, p1, eta_turbine)
+printState(4,w)
+
+# efficiency
+eff = (turbine_work - pump_work)/heat_added
+
+print 'efficiency = ',eff
+
+
+
+
 
-w.setTemperature(273.16)
-w.setState_Tsat(0.0)
-h0 = w.enthalpy_mass()
-for t in [300.0, 350.0, 400.0, 450.0, 500.0]:
-    w.setTemperature(t)
-    w.setState_Tsat(0.0)
-    hf = w.enthalpy_mass()
-    w.setState_Tsat(1.0)
-    hv = w.enthalpy_mass()
-    print t, 0.001*(hf - h0), 0.001*(hv - h0), 0.001*(hv - hf)
 
-for t in [750.0, 800.0, 850.0, 1150.0]:
-    w.setState_TP(t, 2.0e4)
-    print t, w.enthalpy_mass() - h0
     
diff --git a/data/inputs/purefluids.cti b/data/inputs/liquidvapor.cti
similarity index 87%
rename from data/inputs/purefluids.cti
rename to data/inputs/liquidvapor.cti
index a9f52b31d..0ab15984d 100644
--- a/data/inputs/purefluids.cti
+++ b/data/inputs/liquidvapor.cti
@@ -1,38 +1,40 @@
-# These phase definitions actually represent multiphase fluids. They
-# use equations of state in the 'TPX' package, which in turn take most
-# of the equations of state from the compilation 'Thermodynamic
-# Properties in SI', by W. C. Reynolds.
+# These phase definitions represent fluids with complete liquid/vapor
+# equations of state. Depending on conditions, they may represent a
+# single-phase fluid, either liquid or vapor, or a saturated
+# liquid/vapor mixture. They use equations of state in the 'TPX'
+# package, which in turn take most of the equations of state from the
+# compilation 'Thermodynamic Properties in SI', by W. C. Reynolds.
 
 
-pure_fluid(name = "water",
+liquid_vapor(name = "water",
            elements = " O  H ",
            species = "H2O",
            substance_flag = 0,
            initial_state = state(temperature = 300.0,
                                  pressure = OneAtm) ) 
 
-pure_fluid(name = "nitrogen",
+liquid_vapor(name = "nitrogen",
            elements = " N ",
            species = "N2",
            substance_flag = 1,
            initial_state = state(temperature = 300.0,
                                  pressure = OneAtm) )
 
-pure_fluid(name = "methane",
+liquid_vapor(name = "methane",
            elements = " C H ",
            species = "CH4",
            substance_flag = 2,
            initial_state = state(temperature = 300.0,
                                  pressure = OneAtm) ) 
 
-pure_fluid(name = "hydrogen",
+liquid_vapor(name = "hydrogen",
            elements = " H ",
            species = "H2",
            substance_flag = 3,
            initial_state = state(temperature = 300.0,
                                  pressure = OneAtm) ) 
 
-pure_fluid(name = "oxygen",
+liquid_vapor(name = "oxygen",
            elements = " O ",
            species = "O2",
            substance_flag = 4,