ADDED   mttroot/mtt/lib/cr/r/StefanBoltzmann.cr
Index: mttroot/mtt/lib/cr/r/StefanBoltzmann.cr
==================================================================
--- /dev/null
+++ mttroot/mtt/lib/cr/r/StefanBoltzmann.cr
@@ -0,0 +1,53 @@
+%SUMMARY lsin	linear constitutive relationship with sin modulation
+%DESCRIPTION Parameter 1 defines input causality relating to parameter 2
+%DESCRIPTION value is effort, flow or state
+%DESCRIPTION Parameter 2 is the gain corresponding to the causality of
+%DESCRIPTION parameter 1.
+%DESCRIPTION Supported components:
+
+%     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
+%     %%%%% Model Transformation Tools %%%%%
+%     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% Linear constitutive relationship with sin modulation
+
+
+% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% %% Version control history
+% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% %% $Id$
+% %% $Log$
+% %% Revision 1.1  1996/11/02 10:18:25  peterg
+% %% Initial revision
+% %%
+% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+
+OPERATOR lsin;
+
+%DESCRIPTION three port component: EMTF
+FOR ALL gain, input, causality, gain_causality, outport, inport,
+	 m_input, m_causality
+SUCH THAT (
+	(causality = gain_causality) AND (outport = 2)
+	OR
+	(causality NEQ gain_causality) AND (outport = 1)
+	)
+LET lsin(gain_causality, gain, causality, outport, 
+	input, causality, inport,
+	m_input, m_causality, 3)
+	 = sin(m_input)*gain*input;
+
+FOR ALL gain, input, causality, gain_causality, outport, inport,
+	 m_input, m_causality
+SUCH THAT (
+	(causality NEQ gain_causality) AND (outport = 2)
+	OR
+	(causality = gain_causality) AND (outport = 1)
+	)
+LET lsin(gain_causality, gain, causality, outport, 
+	input, causality, inport,
+	m_input, m_causality, 3)
+	 = input/(sin(m_input)*gain);
+
+
+