Browsing by Author "Oduor, Andrew"

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  • Publication
    Publication
    Acoustical properties of compressed earth blocks: Effect of compaction pressure, water hyacinth ash and lime
    (Elsevier, 2023-07-01) Ouma, Justus; Ongwen, Nicholas; Ogam, Erick; Auma, Mercy; Fellah, Z. E. A.; Mageto, Maxwell; Ben Mansour, Mohamed; Oduor, Andrew
    This study assessed the potential use of a mixture of lime and water hyacinth ash (WHA) as binders in fabrication of cylindrical compressed earth blocks (CEBs) with good acoustic absorption properties for building and construction. Different concentrations of the binders and compaction pressures were employed so as to vary the acoustical properties of the fabricated blocks. The geometric and transport parameters of their porous microstructure were recovered through probing using acoustic waves. A low-frequency acoustic wave guide was built for this purpose. It was found out that the transmission coefficient decreased with the compaction pressure, and with addition of lime, while WHA increased the transmission coefficient. The non-acoustical parameters recovered using the equivalent fluid model (JCAL) showed that the variation of the geometry of the microstructure of the blocks is what influences the acoustic transmission coefficient. Thus, the properties of the CEBs can be steered using binder concentration and compaction pressure in a controlled manner.
  • Publication
    Publication
    Water Quality of Selected Fishing Beaches of Lake Victoria Kenyan Gulf
    (Scientific Research, 2020-01) Orina, Paul S.; Onyango, David M.; Lungayia, Henry; Oduor, Andrew; Sifuna, Anthony W.; Otuya, Petronila; Owigar, Rosemary A.; Kowenje, Chrispin B.; Hinzano, Sheban M.
    Lake Victoria the second largest fresh water body in the world located in East Africa is a shared resource between Kenya, Tanzania and Uganda and enjoys a wide range of streams and rivers from as far as Burundi and Rwanda. The lake has environmentally undergone physical, chemical and biological changes in the last four decades, particularly rise in its trophic condition and decline in oxygen level, which affects the water quality and fish population dynamics. This study therefore set out to determine the quality of water in selected fishing beaches of Lake Victoria, Kenya with a view to report the possible pollution levels. pH was highest at Nyamasari and Kotieno (9.3 ± 0.1) and lowest at Nyachebe and Kichinjio (7.08 ± 0.1) whereas temperature was highest at Nyamasari (29.5°C ± 0.0°C) and lowest at Kichinjio (23.4°C ± 0.2°C). DO was highest at Kotieno (10.3 ± 0.2 mgL) and lowest at Seka (2.4 ± 0.1 mgL). Turbidity was highest at Uyoga (125.5 ± 0.90 NTU) and lowest at Osieko (2.7 ± 0.1 NTU). Ammoniacal nitrogen was highest at Dunga (1278.3 ± 0.8 μ∙gl-1) and lowest at Nyamasari (12.4 ± 0.8), all a factor of human activities, lake substratum and effluents from rivers and surface runoff. All parameters assessed showed significant differences across sampling sites and depth except pH which did not vary significantly with distance from lakeshore. Further, all parameters did not show a clear pattern with respect to distance from the lakeshore possibly due to adequate mixing in the gulf. There is a need for further water quality monitoring by seasons to inform policy decisions towards sustainable lake exploitation.