hydrogen technology is becoming ever more relevant because hydrogen use can help containinggreenhouse gas emission if co2 capture and storage techniques are implemented in the hydrogen productiontechnology (when hydrogen is produced from fossil fuels). for this reason this work aims at carryingout a comparative analysis of possible energy scenarios in urban districts: a medium-small italian cit...

in this paper, we introduce the new notion of n-f-clean rings as a generalization of f-clean rings. next, we investigate some properties of such rings. we prove that mn(r) is n-f-clean for any n-f-clean ring r. we also, get a condition under which the de nitions of n-cleanness and n-f-cleanness are equivalent.

THE FEASIBILITY OF TRANSFERRING CLEAN TECHNOLOGY FROM THE UNITED STATES TO CHINA: A CASE STUDY FROM THE PAPER INDUSTRY

let a; b; k 2 k and u ; v 2 u(k). we show for any idempotent e 2 k, ( a 0 b 0 ) is e-clean i ( a 0 u(vb + ka) 0 ) is e-clean and if ( a 0 b 0 ) is 0-clean, ( ua 0 u(vb + ka) 0 ) is too.

Let R be an associative ring with unity. An element a in R is said to be r-clean if a = e+r, where e is an idempotent and r is a regular (von Neumann) element in R. If every element of R is r-clean, then R is called an r-clean ring. In this paper, we prove that the concepts of clean ring and r-clean ring are equivalent for abelian rings. Further we prove that if 0 and 1 are the only idempotents...