I have few public domain articles and related RSS feeds. I split the RSS into php array then splice the array in to three parts. Each part is inserted inside article beginning after one para, in the middle, and the last before last para of article to escape duplicate content flag.

My question is: Is that against the terms of Service of google adsence or the article directory from where I used the article but with author resource box intact. I used the inserted RSS feed items in a separate CSS classs/ ID so that it look separate from the article bit in html code it will be merged.

Is that accepted or against TOS? Any expert opinions?

As far as I can tell you its not against TOS of adsense but its better ti enquire at adsense support.