diff --git a/extensions/BoundaryFunctions.h b/extensions/BoundaryFunctions.h
index 8432668dae9de80bde5da981b6020e03187b5f7c..72861ac029f088a6c49fa51763ecd59fe3c6eefe 100644
--- a/extensions/BoundaryFunctions.h
+++ b/extensions/BoundaryFunctions.h
@@ -107,7 +107,7 @@ public:
 	BoundaryFct2() : AbstractFunction<double, WorldVector<double> >(1), y(0.205), c(6.0) {};
 	BoundaryFct2(double y_, double c_) : AbstractFunction<double, WorldVector<double> >(1), y(y_),c(c_) {};
 	double operator()(const WorldVector<double>& x) const  {  
-		return 1.0/sqr(2.0*y) * sin(m_pi*(*timePtr)/8.0)*c*(y+x[1])*(y-x[1]);
+		return 1.0/sqr(2.0*y) * std::sin(m_pi*(*timePtr)/8.0)*c*(y+x[1])*(y-x[1]);
 	};
 protected: 
 	double y,c;
@@ -119,7 +119,7 @@ public:
 	BoundaryFct2_robin() : AbstractFunction<double, WorldVector<double> >(1), y(0.205), c(6.0) {};
 	BoundaryFct2_robin(double y_, double c_) : AbstractFunction<double, WorldVector<double> >(1), y(y_),c(c_) {};
 	double operator()(const WorldVector<double>& x) const  {  
-		double result = 1.0/sqr(2.0*y) * sin(m_pi*(*timePtr)/8.0)*c*(y+x[1])*(y-x[1]);
+		double result = 1.0/sqr(2.0*y) * std::sin(m_pi*(*timePtr)/8.0)*c*(y+x[1])*(y-x[1]);
 		double n = (x[0]<0.0?-1.0:1.0);
 		return -1.0*result*n;
 	};
@@ -138,8 +138,8 @@ class StokesFlow : public AbstractFunction<WorldVector<double>, WorldVector<doub
       Initfile::get("user parameter->colloidal radius",R, 1);
       Initfile::get("pfc-parameter->density",density, 1);
       Initfile::get("pfc-parameter->r",r, 1);
-      radius = R/(1.0-R) * 2.0*m_pi/sqrt(3.0);
-      D = radius + 2.0*m_pi/sqrt(3.0);
+      radius = R/(1.0-R) * 2.0*m_pi/std::sqrt(3.0);
+      D = radius + 2.0*m_pi/std::sqrt(3.0);
 
       center.set(0.0);
       Initfile::get("user parameter->colloids position[0]",center, 1);
@@ -176,8 +176,8 @@ class StokesFlow_component : public AbstractFunction<double, WorldVector<double>
       Initfile::get("user parameter->colloidal radius",R, 1);
       Initfile::get("pfc-parameter->density",density, 1);
       Initfile::get("pfc-parameter->r",r, 1);
-      radius = R/(1.0-R) * 2.0*m_pi/sqrt(3.0);
-      D = radius + 2.0*m_pi/sqrt(3.0);
+      radius = R/(1.0-R) * 2.0*m_pi/std::sqrt(3.0);
+      D = radius + 2.0*m_pi/std::sqrt(3.0);
 
       center.set(0.0);
       Initfile::get("user parameter->colloids position[0]",center, 1);
@@ -215,8 +215,8 @@ class StokesFlow_robin : public AbstractFunction<double, WorldVector<double> >
       Initfile::get("user parameter->colloidal radius",R, 1);
       Initfile::get("pfc-parameter->density",density, 1);
       Initfile::get("pfc-parameter->r",r, 1);
-      radius = R/(1.0-R) * 2.0*m_pi/sqrt(3.0);
-      D = radius + 2.0*m_pi/sqrt(3.0);
+      radius = R/(1.0-R) * 2.0*m_pi/std::sqrt(3.0);
+      D = radius + 2.0*m_pi/std::sqrt(3.0);
 
       center.set(0.0);
       Initfile::get("user parameter->colloids position[0]",center, 1);