College of Science

      Instant messaging is a form of online, real time form of communication between two or more people based on typed text. IM system has grown rapidly among network users. But most of existing instant messaging systems have severe security problems, people want to retain their privacy and communication should not copy or modified by a third party.This thesis presents the design and implementation of a secure instant messaging system. It achieved security objectives such as data integrity and confidentiality through encryption.

   Nano Li-Ni ferrite samples having the structure Li were prepared by hydrothermal method in two sets from metal chlorides,ferrous sulfate and NaOH. Each set implicated varying x through 0, 0.1,0.3 to 1.0. The samples were without and with adding Fe0.5-0.5x2+. The ratio ofFe3+/ Fe2+ was kept at 1.7. The preparation temperature was 155 °C and pH was equal to 11.

    The aim of the present work was to study the effect of alpha-particles, gammarays and (He-Ne) laser beam on the track registration and optical properties of  CR-39 detectors. Twenty-four detectors divided into five groups. First group:include nine detectors  were exposed to different powers of (1, 5 and 10 mW) of laser beam at  times (5, 10 and 15 min) and then irradiated to alpha-particles from 226 Ra source.