-\begin{block}{\textcolor{white} {Some definitions:}}
-\small
-\begin{enumerate}[i)]
-\item \textcolor{black} {Time spent until death of the first sensor (or cluster head).}
-\item \textcolor{black} {Time spent until death of all wireless sensor nodes in WSN.}
-\item \textcolor{black} {Time spent by WSN in covering each target by at least one sensor.}
-\item \textcolor{black} {Time during which the area of interest is covered by at least k nodes.}
-\item \textcolor{black} {Elapsed time until losing the connectivity or the coverage.}
-\item \bf \textcolor{red} {Time elapsed until the coverage ratio becomes less than a predetermined threshold $\alpha$.}
+\begin{femtoBlock}
+ { Some definitions\\}
+ \begin{enumerate}[i)]
+\item \textcolor{black} {Time spent until death of the first sensor (or cluster head)}
+\item \textcolor{black} {Time spent until death of all wireless sensor nodes in WSN}
+%\item \textcolor{black} {Time spent by WSN in covering each target by at least one sensor}
+\item \textcolor{black} {Time spent in covering area of interest by at least k nodes}
+\item \textcolor{black} {Elapsed time until losing the connectivity or the coverage}
+\item \bf \textcolor{red} {Elapsed time until the coverage ratio becomes less than a predetermined threshold $\alpha$}