let $r$ be an arbitrary ring with identity and $m$ a right $r$-module with $s=$ end$_r(m)$. the module $m$ is called {it rickart} if for any $fin s$, $r_m(f)=se$ for some $e^2=ein s$. we prove that some results of principally projective rings and baer modules can be extended to rickart modules for this general settings.

(MEDICAGO SATIVA): BATCH PH, TIME, TEMPERATURE, AND IONIC STRENGTH STUDIES 1 I. Herrera, 1,2 J.L. Gardea-Torresdey, 1 K.J. Tiemann, 2 J.R. Peralta-Videa, 1 V. Armendariz, and J.G. Parsons 1Department of Chemistry, 500 W. University Ave, University of Texas at El Paso, El Paso, TX 79968; Phone: (915)747-5359; Fax: (915)747-5748. 2Environmental Science and Engineering Ph.D. Program,University of ...