Browsing by Author "Hussen, Ayalew"

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    9,9-Disubstituted Fluorene-Based Polymers: Preparation and Characterization
    (Addis Ababa Universty, 2009-07) Hussen, Ayalew; Mammo, Wendimagegn (Professor)
    A family of conjugated polymers based on 9,9-disubstituted fluorenes and cyanovinylenes were reported. The polymers were synthesized by employing a slightly modified Suzuki coupling polymerization reaction and condensation polymerization utilizing the Knoevenagel reaction. The resulting polymers showed good solubility in chloroform. The energetic positions of the band edges were determined by cyclic voltammetry. The synthesized polymers were characterized by using spectroscopic techniques such as UV-Vis and 1H- NMR. The presented polymers exhibited emission of blue to red colors.
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    Geological Framework for Groundwater Occurrence in Lake Tana Basin, Northwesern Ethiopia, Amhara Region
    (Addis Ababa University, 2010-01) Hussen, Ayalew; Ayenew, Tenalem (PhD)
    The study area is found in northwestern Ethiopia, Amhara National Regional State (ANRS). It is situated in the junction of the three grabens (Gonder, Gorgora &Debretabor). The study area with 15339 km2, comprising the two shield volcanoes( Guna and Choke), Lake Tana and rivers, which is delineated arbitrarily so as to determine whether the geological framework is favorable for ground water occurrence and circulation between them or not. Irrigated methodologies are used t find out the groundwater flow system and hydrochemistry of the study area along with employing the appropriate software like global mapper, serfer, and Arc GIS that facilitate for analysis and interpretations of the data in order to get the output. The secondary data are collected from the concerned offices and same primary data are obtained during the field work. Accordingly, groundwater flow system is considered as shallow and deep aquifer cases and the output indicate that there is the same flow trend within the two flow systems ground water flows west and to the southwest. On the other hand, hydro chemical data analysis part also reveals, evolution of major ions, water types portability of water for human consumption, spatial distribution of some major ions including fluoride and direction of groundwater flow. For example, the water sample from the spring and hand dug well(Guzara) and bore hole(Enfraze) is NaCHO- 3 type, which indicate the presence of evolution where as cold springs mostly from the high lands has the water type Na-CA-HCO3 shows minor evolution. The increasing trends of the physicochemical analysis indicate that there is groundwater out flow towards the Lake area