diff --git a/src/main/java/neqsim/physicalproperties/physicalpropertymethods/commonphasephysicalproperties/viscosity/Viscosity.java b/src/main/java/neqsim/physicalproperties/physicalpropertymethods/commonphasephysicalproperties/viscosity/Viscosity.java
index f064cb04b..ebc04177b 100644
--- a/src/main/java/neqsim/physicalproperties/physicalpropertymethods/commonphasephysicalproperties/viscosity/Viscosity.java
+++ b/src/main/java/neqsim/physicalproperties/physicalpropertymethods/commonphasephysicalproperties/viscosity/Viscosity.java
@@ -10,7 +10,7 @@
  *
  * @author Even Solbraa
  */
-abstract class Viscosity extends CommonPhysicalPropertyMethod implements ViscosityInterface {
+public abstract class Viscosity extends CommonPhysicalPropertyMethod implements ViscosityInterface {
   private static final long serialVersionUID = 1000;
   static Logger logger = LogManager.getLogger(Viscosity.class);
 
diff --git a/src/main/java/neqsim/physicalproperties/physicalpropertymethods/gasphysicalproperties/GasPhysicalPropertyMethod.java b/src/main/java/neqsim/physicalproperties/physicalpropertymethods/gasphysicalproperties/GasPhysicalPropertyMethod.java
index dea072c75..337b904a8 100644
--- a/src/main/java/neqsim/physicalproperties/physicalpropertymethods/gasphysicalproperties/GasPhysicalPropertyMethod.java
+++ b/src/main/java/neqsim/physicalproperties/physicalpropertymethods/gasphysicalproperties/GasPhysicalPropertyMethod.java
@@ -18,13 +18,6 @@ public abstract class GasPhysicalPropertyMethod extends PhysicalPropertyMethod {
   public double[][] binaryEnergyParameter;
   public double[][] binaryMolecularMass;
 
-  /**
-   * <p>
-   * Constructor for GasPhysicalPropertyMethod.
-   * </p>
-   */
-  public GasPhysicalPropertyMethod() {}
-
   /**
    * <p>
    * Constructor for GasPhysicalPropertyMethod.
diff --git a/src/main/java/neqsim/physicalproperties/physicalpropertymethods/gasphysicalproperties/density/Density.java b/src/main/java/neqsim/physicalproperties/physicalpropertymethods/gasphysicalproperties/density/Density.java
index 4323808de..d662044cc 100644
--- a/src/main/java/neqsim/physicalproperties/physicalpropertymethods/gasphysicalproperties/density/Density.java
+++ b/src/main/java/neqsim/physicalproperties/physicalpropertymethods/gasphysicalproperties/density/Density.java
@@ -28,13 +28,13 @@ public class Density extends GasPhysicalPropertyMethod implements DensityInterfa
    * Constructor for Density.
    * </p>
    *
-   * @param gasPhase a
+   * @param phase a
    *        {@link neqsim.physicalproperties.physicalpropertysystem.PhysicalPropertiesInterface}
    *        object
    */
   public Density(
-      neqsim.physicalproperties.physicalpropertysystem.PhysicalPropertiesInterface gasPhase) {
-    this.gasPhase = gasPhase;
+      neqsim.physicalproperties.physicalpropertysystem.PhysicalPropertiesInterface phase) {
+    super(phase);
   }
 
   /** {@inheritDoc} */
diff --git a/src/main/java/neqsim/physicalproperties/physicalpropertymethods/gasphysicalproperties/viscosity/Viscosity.java b/src/main/java/neqsim/physicalproperties/physicalpropertymethods/gasphysicalproperties/viscosity/Viscosity.java
index 24ca65cc9..f64303559 100644
--- a/src/main/java/neqsim/physicalproperties/physicalpropertymethods/gasphysicalproperties/viscosity/Viscosity.java
+++ b/src/main/java/neqsim/physicalproperties/physicalpropertymethods/gasphysicalproperties/viscosity/Viscosity.java
@@ -6,11 +6,11 @@
 import neqsim.physicalproperties.physicalpropertymethods.methodinterface.ViscosityInterface;
 
 /**
- * * Abstract class for Viscosity property.
+ * Abstract class for Viscosity property.
  *
  * @author Even Solbraa
  */
-abstract class Viscosity extends GasPhysicalPropertyMethod implements ViscosityInterface {
+public abstract class Viscosity extends GasPhysicalPropertyMethod implements ViscosityInterface {
   private static final long serialVersionUID = 1000;
   static Logger logger = LogManager.getLogger(Viscosity.class);
 
diff --git a/src/main/java/neqsim/physicalproperties/physicalpropertymethods/liquidphysicalproperties/LiquidPhysicalPropertyMethod.java b/src/main/java/neqsim/physicalproperties/physicalpropertymethods/liquidphysicalproperties/LiquidPhysicalPropertyMethod.java
index b4e584b31..65f38884f 100644
--- a/src/main/java/neqsim/physicalproperties/physicalpropertymethods/liquidphysicalproperties/LiquidPhysicalPropertyMethod.java
+++ b/src/main/java/neqsim/physicalproperties/physicalpropertymethods/liquidphysicalproperties/LiquidPhysicalPropertyMethod.java
@@ -1,6 +1,7 @@
 package neqsim.physicalproperties.physicalpropertymethods.liquidphysicalproperties;
 
 import neqsim.physicalproperties.physicalpropertymethods.PhysicalPropertyMethod;
+import neqsim.physicalproperties.physicalpropertysystem.PhysicalPropertiesInterface;
 
 /**
  * <p>
@@ -10,18 +11,11 @@
  * @author Even Solbraa
  * @version $Id: $Id
  */
-public class LiquidPhysicalPropertyMethod extends PhysicalPropertyMethod {
+public abstract class LiquidPhysicalPropertyMethod extends PhysicalPropertyMethod {
   private static final long serialVersionUID = 1000;
 
   protected neqsim.physicalproperties.physicalpropertysystem.PhysicalPropertiesInterface liquidPhase;
 
-  /**
-   * <p>
-   * Constructor for LiquidPhysicalPropertyMethod.
-   * </p>
-   */
-  public LiquidPhysicalPropertyMethod() {}
-
   /**
    * <p>
    * Constructor for LiquidPhysicalPropertyMethod.
@@ -31,15 +25,13 @@ public LiquidPhysicalPropertyMethod() {}
    *        {@link neqsim.physicalproperties.physicalpropertysystem.PhysicalPropertiesInterface}
    *        object
    */
-  public LiquidPhysicalPropertyMethod(
-      neqsim.physicalproperties.physicalpropertysystem.PhysicalPropertiesInterface liquidPhase) {
-    this.liquidPhase = liquidPhase;
+  public LiquidPhysicalPropertyMethod(PhysicalPropertiesInterface phase) {
+    setPhase(phase);
   }
 
   /** {@inheritDoc} */
   @Override
-  public void setPhase(
-      neqsim.physicalproperties.physicalpropertysystem.PhysicalPropertiesInterface phase) {
+  public void setPhase(PhysicalPropertiesInterface phase) {
     this.liquidPhase = phase;
   }
 }
diff --git a/src/main/java/neqsim/physicalproperties/physicalpropertymethods/liquidphysicalproperties/density/Costald.java b/src/main/java/neqsim/physicalproperties/physicalpropertymethods/liquidphysicalproperties/density/Costald.java
index 5edb9417e..d3c45ae4d 100644
--- a/src/main/java/neqsim/physicalproperties/physicalpropertymethods/liquidphysicalproperties/density/Costald.java
+++ b/src/main/java/neqsim/physicalproperties/physicalpropertymethods/liquidphysicalproperties/density/Costald.java
@@ -34,7 +34,7 @@ public class Costald extends LiquidPhysicalPropertyMethod implements DensityInte
    */
   public Costald(
       neqsim.physicalproperties.physicalpropertysystem.PhysicalPropertiesInterface liquidPhase) {
-    this.liquidPhase = liquidPhase;
+    super(liquidPhase);
   }
 
   /** {@inheritDoc} */
diff --git a/src/main/java/neqsim/physicalproperties/physicalpropertymethods/liquidphysicalproperties/density/Density.java b/src/main/java/neqsim/physicalproperties/physicalpropertymethods/liquidphysicalproperties/density/Density.java
index 128fdc4c5..0e4f85c15 100644
--- a/src/main/java/neqsim/physicalproperties/physicalpropertymethods/liquidphysicalproperties/density/Density.java
+++ b/src/main/java/neqsim/physicalproperties/physicalpropertymethods/liquidphysicalproperties/density/Density.java
@@ -33,8 +33,8 @@ public class Density extends LiquidPhysicalPropertyMethod implements DensityInte
    *        object
    */
   public Density(
-      neqsim.physicalproperties.physicalpropertysystem.PhysicalPropertiesInterface liquidPhase) {
-    this.liquidPhase = liquidPhase;
+      neqsim.physicalproperties.physicalpropertysystem.PhysicalPropertiesInterface phase) {
+    super(phase);
   }
 
   /** {@inheritDoc} */
diff --git a/src/main/java/neqsim/physicalproperties/physicalpropertymethods/solidphysicalproperties/SolidPhysicalPropertyMethod.java b/src/main/java/neqsim/physicalproperties/physicalpropertymethods/solidphysicalproperties/SolidPhysicalPropertyMethod.java
index 79c02f261..6ec51c56d 100644
--- a/src/main/java/neqsim/physicalproperties/physicalpropertymethods/solidphysicalproperties/SolidPhysicalPropertyMethod.java
+++ b/src/main/java/neqsim/physicalproperties/physicalpropertymethods/solidphysicalproperties/SolidPhysicalPropertyMethod.java
@@ -10,7 +10,7 @@
  * @author Even Solbraa
  * @version $Id: $Id
  */
-public class SolidPhysicalPropertyMethod extends PhysicalPropertyMethod {
+public abstract class SolidPhysicalPropertyMethod extends PhysicalPropertyMethod {
   private static final long serialVersionUID = 1000;
 
   protected neqsim.physicalproperties.physicalpropertysystem.PhysicalPropertiesInterface solidPhase;
@@ -25,8 +25,8 @@ public class SolidPhysicalPropertyMethod extends PhysicalPropertyMethod {
    *        object
    */
   public SolidPhysicalPropertyMethod(
-      neqsim.physicalproperties.physicalpropertysystem.PhysicalPropertiesInterface solidPhase) {
-    this.solidPhase = solidPhase;
+      neqsim.physicalproperties.physicalpropertysystem.PhysicalPropertiesInterface phase) {
+    setPhase(phase);
   }
 
   /** {@inheritDoc} */
diff --git a/src/main/java/neqsim/physicalproperties/physicalpropertysystem/PhysicalProperties.java b/src/main/java/neqsim/physicalproperties/physicalpropertysystem/PhysicalProperties.java
index d55ca97f2..0384a996a 100644
--- a/src/main/java/neqsim/physicalproperties/physicalpropertysystem/PhysicalProperties.java
+++ b/src/main/java/neqsim/physicalproperties/physicalpropertysystem/PhysicalProperties.java
@@ -8,6 +8,7 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
+import neqsim.physicalproperties.mixingrule.PhysicalPropertyMixingRuleInterface;
 import neqsim.physicalproperties.physicalpropertymethods.commonphasephysicalproperties.conductivity.PFCTConductivityMethodMod86;
 import neqsim.physicalproperties.physicalpropertymethods.commonphasephysicalproperties.diffusivity.CorrespondingStatesDiffusivity;
 import neqsim.physicalproperties.physicalpropertymethods.commonphasephysicalproperties.viscosity.FrictionTheoryViscosityMethod;
@@ -16,9 +17,13 @@
 import neqsim.physicalproperties.physicalpropertymethods.commonphasephysicalproperties.viscosity.PFCTViscosityMethodMod86;
 import neqsim.physicalproperties.physicalpropertymethods.gasphysicalproperties.conductivity.ChungConductivityMethod;
 import neqsim.physicalproperties.physicalpropertymethods.gasphysicalproperties.diffusivity.WilkeLeeDiffusivity;
+import neqsim.physicalproperties.physicalpropertymethods.liquidphysicalproperties.density.Costald;
 import neqsim.physicalproperties.physicalpropertymethods.liquidphysicalproperties.diffusivity.AmineDiffusivity;
 import neqsim.physicalproperties.physicalpropertymethods.liquidphysicalproperties.diffusivity.SiddiqiLucasMethod;
 import neqsim.physicalproperties.physicalpropertymethods.methodinterface.ConductivityInterface;
+import neqsim.physicalproperties.physicalpropertymethods.methodinterface.DensityInterface;
+import neqsim.physicalproperties.physicalpropertymethods.methodinterface.DiffusivityInterface;
+import neqsim.physicalproperties.physicalpropertymethods.methodinterface.ViscosityInterface;
 import neqsim.thermo.ThermodynamicConstantsInterface;
 import neqsim.thermo.phase.PhaseInterface;
 
@@ -38,12 +43,11 @@ public abstract class PhysicalProperties
   public PhaseInterface phase;
   protected int binaryDiffusionCoefficientMethod;
   protected int multicomponentDiffusionMethod;
-  private neqsim.physicalproperties.mixingrule.PhysicalPropertyMixingRuleInterface mixingRule =
-      null;
-  public neqsim.physicalproperties.physicalpropertymethods.methodinterface.ConductivityInterface conductivityCalc;
-  public neqsim.physicalproperties.physicalpropertymethods.methodinterface.ViscosityInterface viscosityCalc;
-  public neqsim.physicalproperties.physicalpropertymethods.methodinterface.DiffusivityInterface diffusivityCalc;
-  public neqsim.physicalproperties.physicalpropertymethods.methodinterface.DensityInterface densityCalc;
+  private PhysicalPropertyMixingRuleInterface mixingRule = null;
+  public ConductivityInterface conductivityCalc;
+  public ViscosityInterface viscosityCalc;
+  public DiffusivityInterface diffusivityCalc;
+  public DensityInterface densityCalc;
   public double kinematicViscosity = 0;
   public double density = 0;
   public double viscosity = 0;
@@ -105,14 +109,13 @@ public PhaseInterface getPhase() {
 
   /** {@inheritDoc} */
   @Override
-  public neqsim.physicalproperties.mixingrule.PhysicalPropertyMixingRuleInterface getMixingRule() {
+  public PhysicalPropertyMixingRuleInterface getMixingRule() {
     return mixingRule;
   }
 
   /** {@inheritDoc} */
   @Override
-  public void setMixingRule(
-      neqsim.physicalproperties.mixingrule.PhysicalPropertyMixingRuleInterface mixingRule) {
+  public void setMixingRule(PhysicalPropertyMixingRuleInterface mixingRule) {
     this.mixingRule = mixingRule;
   }
 
@@ -124,7 +127,7 @@ public void setMixingRuleNull() {
 
   /** {@inheritDoc} */
   @Override
-  public neqsim.physicalproperties.physicalpropertymethods.methodinterface.ViscosityInterface getViscosityModel() {
+  public ViscosityInterface getViscosityModel() {
     return viscosityCalc;
   }
 
@@ -136,9 +139,7 @@ public void setDensityModel(String model) {
           new neqsim.physicalproperties.physicalpropertymethods.liquidphysicalproperties.density.Density(
               this);
     } else if ("Costald".equals(model)) {
-      densityCalc =
-          new neqsim.physicalproperties.physicalpropertymethods.liquidphysicalproperties.density.Costald(
-              this);
+      densityCalc = new Costald(this);
     }
   }
 
diff --git a/src/main/java/neqsim/thermo/component/ComponentGEUniquacmodifiedHV.java b/src/main/java/neqsim/thermo/component/ComponentGEUniquacmodifiedHV.java
index 86d78508f..609e32ab3 100644
--- a/src/main/java/neqsim/thermo/component/ComponentGEUniquacmodifiedHV.java
+++ b/src/main/java/neqsim/thermo/component/ComponentGEUniquacmodifiedHV.java
@@ -14,7 +14,7 @@
  *
  * @author Even Solbraa
  */
-abstract class ComponentGEUniquacmodifiedHV extends ComponentGEUniquac {
+public abstract class ComponentGEUniquacmodifiedHV extends ComponentGEUniquac {
   private static final long serialVersionUID = 1000;
 
   /**
diff --git a/src/main/java/neqsim/thermo/component/ComponentPrCPA.java b/src/main/java/neqsim/thermo/component/ComponentPrCPA.java
index 2f42683da..a261a4e6e 100644
--- a/src/main/java/neqsim/thermo/component/ComponentPrCPA.java
+++ b/src/main/java/neqsim/thermo/component/ComponentPrCPA.java
@@ -8,7 +8,7 @@
  *
  * @author Even Solbraa
  */
-abstract class ComponentPrCPA extends ComponentPR implements ComponentCPAInterface {
+public abstract class ComponentPrCPA extends ComponentPR implements ComponentCPAInterface {
   private static final long serialVersionUID = 1000;
 
   int cpaon = 1;