Update README.md

Author: taufer

README.md

@@ -40,6 +40,6 @@ Detailed setup instructions are provided in **Module 1**.
 
 ## Acknowledgment
 
-This material is based upon work supported by the **National Science Foundation (NSF)** under Grant No. **2138811**.2138811.
+This material is based upon work supported by the **National Science Foundation (NSF)** under Grant No. **2138811**.
 
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