Critiquing My Paragraph

The properties of materials -- plastic bags to turbine 
                              ^Are these  materials?         
engine blades -- are "tuned" to meet special requirements. 
This tuning often involves adding or controlling defects, 
conventionally through extensive experimental "trial 
^usually?             ^& expensive?
and error" to achieve success.  Theoretical simulations 
can speed this tuning process by quickly identifying a 
likely experimental path.  
^promising?
The picture displays the effect of adding two extra silicon 
atoms -- called interstitial atoms -- to a perfect 
                  ^interstitials? Do you need such a 
                  technical term; how about using defect 
                  and connect with early word? 
silicon crystal.  That there are two extra atoms can be 
seen by mentally removing two of the the three red atoms 
forming the central triangle; the remaining red atoms relax 
to a plane aligned with the green plane underneath.  This 
two-interstitial cluster can move easily through the crystal 
^Again avoid two-interstitials term
and the ever worse later: "di-interstitial."
forming even larger clusters (see second picture).  The 
                             ^avoid but use second
                             picture in the talk.
theoretical effort here is to quickly identify the moving 
di-interstitials.  Three such di-interstitial patterns 
were selected automatically out of a 100,000 time-step
                                     ^Is the goal
             to determine the likely properties from a given set 
             of defects, or how to produce a given set of defects?
stimulation.  Such quick pattern identification is an 
important step in winnowing down the experimental route 
to tuning a material for effective use, in this case a 
computer chip.  
^This is best stress point of paragraph.
What does it have to do with take-home message?