diff --git a/src/main/java/neqsim/physicalProperties/physicalPropertyMethods/solidPhysicalProperties/diffusivity/Diffusivity.java b/src/main/java/neqsim/physicalProperties/physicalPropertyMethods/solidPhysicalProperties/diffusivity/Diffusivity.java
index 18b9cb1d04..c0d651ab66 100644
--- a/src/main/java/neqsim/physicalProperties/physicalPropertyMethods/solidPhysicalProperties/diffusivity/Diffusivity.java
+++ b/src/main/java/neqsim/physicalProperties/physicalPropertyMethods/solidPhysicalProperties/diffusivity/Diffusivity.java
@@ -101,6 +101,6 @@ public double getFickBinaryDiffusionCoefficient(int i, int j) {
   /** {@inheritDoc} */
   @Override
   public double calcBinaryDiffusionCoefficient(int i, int j, int method) {
-    throw new UnsupportedOperationException("Not supported yet.");
+    throw new UnsupportedOperationException("Unimplemented method 'calcBinaryDiffusionCoefficient");
   }
 }
diff --git a/src/main/java/neqsim/processSimulation/SimulationBaseClass.java b/src/main/java/neqsim/processSimulation/SimulationBaseClass.java
index affaa89134..e2489859a6 100644
--- a/src/main/java/neqsim/processSimulation/SimulationBaseClass.java
+++ b/src/main/java/neqsim/processSimulation/SimulationBaseClass.java
@@ -2,6 +2,7 @@
 
 import java.util.UUID;
 import neqsim.util.NamedBaseClass;
+import neqsim.util.exception.InvalidInputException;
 
 /**
  * Base class for process simulation objects.
@@ -20,7 +21,9 @@ public abstract class SimulationBaseClass extends NamedBaseClass implements Simu
   protected double time = 0;
 
   /**
-   * <p>Constructor for SimulationBaseClass.</p>
+   * <p>
+   * Constructor for SimulationBaseClass.
+   * </p>
    *
    * @param name a {@link java.lang.String} object
    */
@@ -67,8 +70,8 @@ public void setTime(double value) {
   /** {@inheritDoc} */
   public void increaseTime(double dt) {
     if (dt < 0) {
-      throw new UnsupportedOperationException(
-          "Input dt is negative - not allowed to go backwards in time.");
+      throw new RuntimeException(new InvalidInputException(this, "increaseTime", "dt",
+          "Negative values are not allowed. Not possible to go backwards in time."));
     }
     this.time = this.time + dt;
   }
diff --git a/src/main/java/neqsim/thermo/phase/PhaseDesmukhMather.java b/src/main/java/neqsim/thermo/phase/PhaseDesmukhMather.java
index cda993906d..1ff452536a 100644
--- a/src/main/java/neqsim/thermo/phase/PhaseDesmukhMather.java
+++ b/src/main/java/neqsim/thermo/phase/PhaseDesmukhMather.java
@@ -4,6 +4,8 @@
 import org.apache.logging.log4j.Logger;
 import neqsim.thermo.component.ComponentDesmukhMather;
 import neqsim.thermo.component.ComponentGEInterface;
+import neqsim.util.exception.IsNaNException;
+import neqsim.util.exception.TooManyIterationsException;
 
 /**
  * <p>
@@ -95,6 +97,25 @@ && getComponents()[k].getComponentName().equals("MDEA")) {
     }
   }
 
+  /** {@inheritDoc} */
+  @Override
+  public void setAlpha(double[][] alpha) {
+    throw new UnsupportedOperationException("Unimplemented method 'setAlpha'");
+  }
+
+  /**
+   * <p>
+   * Getter for the field <code>aij</code>.
+   * </p>
+   *
+   * @param i a int
+   * @param j a int
+   * @return a double
+   */
+  public double getAij(int i, int j) {
+    return aij[i][j];
+  }
+
   /**
    * <p>
    * Setter for the field <code>aij</code>.
@@ -113,14 +134,26 @@ public void setAij(double[][] alpha) {
    * Setter for the field <code>bij</code>.
    * </p>
    *
-   * @param Dij an array of {@link double} objects
+   * @param Bij an array of {@link double} objects
    */
-  public void setBij(double[][] Dij) {
-    for (int i = 0; i < Dij.length; i++) {
-      System.arraycopy(bij[i], 0, this.bij[i], 0, Dij[0].length);
+  public void setBij(double[][] Bij) {
+    for (int i = 0; i < Bij.length; i++) {
+      System.arraycopy(bij[i], 0, this.bij[i], 0, Bij[0].length);
     }
   }
 
+  /** {@inheritDoc} */
+  @Override
+  public void setDij(double[][] Dij) {
+    throw new UnsupportedOperationException("Unimplemented method 'setDij'");
+  }
+
+  /** {@inheritDoc} */
+  @Override
+  public void setDijT(double[][] DijT) {
+    throw new UnsupportedOperationException("Unimplemented method 'setDijT'");
+  }
+
   /**
    * <p>
    * getBetaDesMatij.
@@ -134,19 +167,6 @@ public double getBetaDesMatij(int i, int j) {
     return aij[i][j] + bij[i][j] * temperature;
   }
 
-  /**
-   * <p>
-   * Getter for the field <code>aij</code>.
-   * </p>
-   *
-   * @param i a int
-   * @param j a int
-   * @return a double
-   */
-  public double getAij(int i, int j) {
-    return aij[i][j];
-  }
-
   /**
    * <p>
    * Getter for the field <code>bij</code>.
@@ -262,4 +282,10 @@ public double getSolventMolarMass() {
     }
     return molesMass / moles;
   }
+
+  @Override
+  public double molarVolume(double pressure, double temperature, double A, double B, PhaseType pt)
+      throws IsNaNException, TooManyIterationsException {
+    throw new UnsupportedOperationException("Unimplemented method 'molarVolume'");
+  }
 }
diff --git a/src/main/java/neqsim/thermo/phase/PhaseDuanSun.java b/src/main/java/neqsim/thermo/phase/PhaseDuanSun.java
index 2978c7f7be..9dbfe21803 100644
--- a/src/main/java/neqsim/thermo/phase/PhaseDuanSun.java
+++ b/src/main/java/neqsim/thermo/phase/PhaseDuanSun.java
@@ -1,6 +1,8 @@
 package neqsim.thermo.phase;
 
 import neqsim.thermo.component.ComponentGeDuanSun;
+import neqsim.util.exception.IsNaNException;
+import neqsim.util.exception.TooManyIterationsException;
 
 /**
  * <p>
@@ -59,6 +61,12 @@ public void setDij(double[][] Dij) {
     }
   }
 
+  /** {@inheritDoc} */
+  @Override
+  public void setDijT(double[][] DijT) {
+    throw new UnsupportedOperationException("Unimplemented method 'setDijT'");
+  }
+
   /** {@inheritDoc} */
   @Override
   public double getExcessGibbsEnergy() {
@@ -111,4 +119,10 @@ public double getExcessGibbsEnergy(PhaseInterface phase, int numberOfComponents,
   public double getGibbsEnergy() {
     return R * temperature * numberOfMolesInPhase * (GE + Math.log(pressure));
   }
+
+  @Override
+  public double molarVolume(double pressure, double temperature, double A, double B, PhaseType pt)
+      throws IsNaNException, TooManyIterationsException {
+    throw new UnsupportedOperationException("Unimplemented method 'molarVolume'");
+  }
 }
diff --git a/src/main/java/neqsim/thermo/phase/PhaseGE.java b/src/main/java/neqsim/thermo/phase/PhaseGE.java
index 1e48be4610..df8797e8a0 100644
--- a/src/main/java/neqsim/thermo/phase/PhaseGE.java
+++ b/src/main/java/neqsim/thermo/phase/PhaseGE.java
@@ -22,7 +22,7 @@
  * @author Even Solbraa
  * @version $Id: $Id
  */
-public class PhaseGE extends Phase implements PhaseGEInterface {
+public abstract class PhaseGE extends Phase implements PhaseGEInterface {
   private static final long serialVersionUID = 1000;
   static Logger logger = LogManager.getLogger(PhaseGE.class);
 
@@ -133,29 +133,6 @@ public void resetMixingRule(int type) {
     mixRuleEos = mixSelect.resetMixingRule(2, this);
   }
 
-  /** {@inheritDoc} */
-  @Override
-  public double molarVolume(double pressure, double temperature, double A, double B, PhaseType pt) {
-    return 1;
-  }
-
-  /**
-   * <p>
-   * molarVolumeAnalytic.
-   * </p>
-   *
-   * @param pressure a double
-   * @param temperature a double
-   * @param A a double
-   * @param B a double
-   * @param phase a int
-   * @return a double
-   */
-  public double molarVolumeAnalytic(double pressure, double temperature, double A, double B,
-      int phase) {
-    return 1;
-  }
-
   /** {@inheritDoc} */
   @Override
   public void addComponent(String name, double moles, double molesInPhase, int compNumber) {
@@ -163,54 +140,6 @@ public void addComponent(String name, double moles, double molesInPhase, int com
     // TODO: compNumber not in use
   }
 
-  /**
-   * <p>
-   * setAlpha.
-   * </p>
-   *
-   * @param alpha an array of {@link double} objects
-   */
-  public void setAlpha(double[][] alpha) {}
-
-  /**
-   * <p>
-   * setDij.
-   * </p>
-   *
-   * @param Dij an array of {@link double} objects
-   */
-  public void setDij(double[][] Dij) {}
-
-  /** {@inheritDoc} */
-  @Override
-  public double getExcessGibbsEnergy() {
-    logger.error("this getExcessGibbsEnergy should never be used.......");
-    return 0;
-  }
-
-  /** {@inheritDoc} */
-  @Override
-  public double getExcessGibbsEnergy(PhaseInterface phase, int numberOfComponents,
-      double temperature, double pressure, PhaseType pt) {
-    logger.error("this getExcessGibbsEnergy should never be used.......");
-    return 0;
-  }
-
-  /** {@inheritDoc} */
-  @Override
-  public double getGibbsEnergy() {
-    return 0;
-  }
-
-  /**
-   * <p>
-   * setDijT.
-   * </p>
-   *
-   * @param DijT an array of {@link double} objects
-   */
-  public void setDijT(double[][] DijT) {}
-
   /** {@inheritDoc} */
   @Override
   public double getActivityCoefficientSymetric(int k) {
diff --git a/src/main/java/neqsim/thermo/phase/PhaseGEInterface.java b/src/main/java/neqsim/thermo/phase/PhaseGEInterface.java
index 7e19dad57f..12d413d3ea 100644
--- a/src/main/java/neqsim/thermo/phase/PhaseGEInterface.java
+++ b/src/main/java/neqsim/thermo/phase/PhaseGEInterface.java
@@ -29,4 +29,31 @@ public interface PhaseGEInterface {
    */
   public double getExcessGibbsEnergy(PhaseInterface phase, int numberOfComponents,
       double temperature, double pressure, PhaseType pt);
+
+  /**
+   * <p>
+   * setAlpha.
+   * </p>
+   *
+   * @param alpha an array of {@link double} objects
+   */
+  public void setAlpha(double[][] alpha);
+
+  /**
+   * <p>
+   * setDij.
+   * </p>
+   *
+   * @param Dij an array of {@link double} objects
+   */
+  public void setDij(double[][] Dij);
+
+  /**
+   * <p>
+   * setDijT.
+   * </p>
+   *
+   * @param DijT an array of {@link double} objects
+   */
+  public void setDijT(double[][] DijT);
 }
diff --git a/src/main/java/neqsim/thermo/phase/PhaseGENRTL.java b/src/main/java/neqsim/thermo/phase/PhaseGENRTL.java
index e10e4adb17..6f273839e7 100644
--- a/src/main/java/neqsim/thermo/phase/PhaseGENRTL.java
+++ b/src/main/java/neqsim/thermo/phase/PhaseGENRTL.java
@@ -8,6 +8,8 @@
 
 import neqsim.thermo.component.ComponentGEInterface;
 import neqsim.thermo.component.ComponentGeNRTL;
+import neqsim.util.exception.IsNaNException;
+import neqsim.util.exception.TooManyIterationsException;
 
 /**
  * <p>
@@ -97,6 +99,12 @@ public void setDij(double[][] Dij) {
     }
   }
 
+  /** {@inheritDoc} */
+  @Override
+  public void setDijT(double[][] DijT) {
+    throw new UnsupportedOperationException("Unimplemented method 'setDijT'");
+  }
+
   /** {@inheritDoc} */
   @Override
   public double getExcessGibbsEnergy() {
@@ -124,4 +132,10 @@ public double getExcessGibbsEnergy(PhaseInterface phase, int numberOfComponents,
   public double getGibbsEnergy() {
     return R * temperature * numberOfMolesInPhase * (GE + Math.log(pressure));
   }
+
+  @Override
+  public double molarVolume(double pressure, double temperature, double A, double B, PhaseType pt)
+      throws IsNaNException, TooManyIterationsException {
+    throw new UnsupportedOperationException("Unimplemented method 'molarVolume'");
+  }
 }
diff --git a/src/main/java/neqsim/thermo/phase/PhaseGEUniquac.java b/src/main/java/neqsim/thermo/phase/PhaseGEUniquac.java
index 1538d546be..fad0aaa1e2 100644
--- a/src/main/java/neqsim/thermo/phase/PhaseGEUniquac.java
+++ b/src/main/java/neqsim/thermo/phase/PhaseGEUniquac.java
@@ -9,6 +9,8 @@
 import neqsim.thermo.ThermodynamicModelSettings;
 import neqsim.thermo.component.ComponentGEInterface;
 import neqsim.thermo.component.ComponentGEUniquac;
+import neqsim.util.exception.IsNaNException;
+import neqsim.util.exception.TooManyIterationsException;
 
 /**
  * <p>
@@ -65,6 +67,24 @@ public PhaseGEUniquac(PhaseInterface phase, double[][] alpha, double[][] Dij, St
     }
   }
 
+  /** {@inheritDoc} */
+  @Override
+  public void setAlpha(double[][] alpha) {
+    throw new UnsupportedOperationException("Unimplemented method 'setAlpha'");
+  }
+
+  /** {@inheritDoc} */
+  @Override
+  public void setDij(double[][] Dij) {
+    throw new UnsupportedOperationException("Unimplemented method 'setDij'");
+  }
+
+  /** {@inheritDoc} */
+  @Override
+  public void setDijT(double[][] DijT) {
+    throw new UnsupportedOperationException("Unimplemented method 'setDijT'");
+  }
+
   /** {@inheritDoc} */
   @Override
   public void addComponent(String name, double moles, double molesInPhase, int compNumber) {
@@ -99,4 +119,10 @@ public double getExcessGibbsEnergy(PhaseInterface phase, int numberOfComponents,
 
     return R * temperature * numberOfMolesInPhase * GE;
   }
+
+  @Override
+  public double molarVolume(double pressure, double temperature, double A, double B, PhaseType pt)
+      throws IsNaNException, TooManyIterationsException {
+    throw new UnsupportedOperationException("Unimplemented method 'molarVolume'");
+  }
 }
diff --git a/src/main/java/neqsim/thermo/phase/PhaseGEWilson.java b/src/main/java/neqsim/thermo/phase/PhaseGEWilson.java
index 0d2bc6704d..19580771f4 100644
--- a/src/main/java/neqsim/thermo/phase/PhaseGEWilson.java
+++ b/src/main/java/neqsim/thermo/phase/PhaseGEWilson.java
@@ -2,6 +2,8 @@
 
 import neqsim.thermo.ThermodynamicModelSettings;
 import neqsim.thermo.component.ComponentGEWilson;
+import neqsim.util.exception.IsNaNException;
+import neqsim.util.exception.TooManyIterationsException;
 
 /**
  * <p>
@@ -50,6 +52,24 @@ public PhaseGEWilson(PhaseInterface phase, double[][] alpha, double[][] Dij, Str
     }
   }
 
+  /** {@inheritDoc} */
+  @Override
+  public void setAlpha(double[][] alpha) {
+    throw new UnsupportedOperationException("Unimplemented method 'setAlpha'");
+  }
+
+  /** {@inheritDoc} */
+  @Override
+  public void setDij(double[][] Dij) {
+    throw new UnsupportedOperationException("Unimplemented method 'setDij'");
+  }
+
+  /** {@inheritDoc} */
+  @Override
+  public void setDijT(double[][] DijT) {
+    throw new UnsupportedOperationException("Unimplemented method 'setDijT'");
+  }
+
   /** {@inheritDoc} */
   @Override
   public void addComponent(String name, double moles, double molesInPhase, int compNumber) {
@@ -89,4 +109,10 @@ public double getExcessGibbsEnergy(PhaseInterface phase, int numberOfComponents,
 
     return R * temperature * numberOfMolesInPhase * GE;
   }
+
+  @Override
+  public double molarVolume(double pressure, double temperature, double A, double B, PhaseType pt)
+      throws IsNaNException, TooManyIterationsException {
+    throw new UnsupportedOperationException("Unimplemented method 'molarVolume'");
+  }
 }
diff --git a/src/main/java/neqsim/util/exception/NotImplementedException.java b/src/main/java/neqsim/util/exception/NotImplementedException.java
new file mode 100644
index 0000000000..8b6856e9d0
--- /dev/null
+++ b/src/main/java/neqsim/util/exception/NotImplementedException.java
@@ -0,0 +1,32 @@
+package neqsim.util.exception;
+
+/**
+ * <p>
+ * NotImplementedException class.
+ * </p>
+ *
+ * @author Åsmund Våge Fannemel
+ */
+public class NotImplementedException extends neqsim.util.exception.ThermoException {
+  private static final long serialVersionUID = 1000;
+
+  /**
+   * Constructs a <code>NotImplementedException</code> with a standard error message.
+   *
+   * @param className Class that exception is raised from
+   * @param methodName Method that exception is raised from
+   */
+  public NotImplementedException(String className, String methodName) {
+    super(className, methodName, "Function not implemented");
+  }
+
+  /**
+   * Constructs a <code>NotImplementedException</code> with a standard error message.
+   *
+   * @param obj object that exception is raised from
+   * @param methodName method that exception is raised from
+   */
+  public NotImplementedException(Object obj, String methodName) {
+    this(obj.getClass().getSimpleName(), methodName);
+  }
+}
diff --git a/src/main/java/neqsim/util/exception/ThermoException.java b/src/main/java/neqsim/util/exception/ThermoException.java
index c574e49b0d..11a59874fc 100644
--- a/src/main/java/neqsim/util/exception/ThermoException.java
+++ b/src/main/java/neqsim/util/exception/ThermoException.java
@@ -14,7 +14,7 @@
  * @author Even Solbraa
  * @version $Id: $Id
  */
-public class ThermoException extends java.lang.Exception {
+public abstract class ThermoException extends java.lang.Exception {
   private static final long serialVersionUID = 1000;
 
   /**