Update scm/doc/TechGuide/chap_hsd.tex

Co-authored-by: Michael Kavulich <kavulich@ucar.edu>

scm/doc/TechGuide/chap_hsd.tex

@@ -57,7 +57,7 @@ \subsection{Enabling the CCPP Suite Simulator}
 
 \subsection{Modifying the CCPP Suite Definition File}
 
-The SDF needs to be modified to include the CSS scheme, and any interstitial schemes needed for your host application. Here we will illustrate how to use the CSS within SCM (UFS) physics, for which all applications use a physics SDF with mixture of process-split and time-split physics schemes.
+The SDF needs to be modified to include the CSS scheme, and any interstitial schemes needed for your host application. Here we will illustrate how to use the CSS within SCM (UFS) physics, for which all applications use a physics SDF with a mixture of process-split and time-split physics schemes.
 In general,
 \begin{itemize}
 \item for SDFs that contain ONLY process-split schemes, the CSS can be added to the end of the SDF for all configurations. In this case we have the flexibility to switch ``on/off'' any combination of active physics and simulated physics at runtime, via namelist, with the same modified SDF.