SynopsisThe thermal and oxidative degradation of poly( phenylene sulfide) and perfluoropoly-(phenylene sulfide) have been studied by a weight-loss method. The products of breakdown in vacuum have also been analyzed. The poly(pheny1ene sulfide) is more thermally stable in inert and oxidizing atmospheres than the fully fluorinated analog. The breakdown products can be accounted for by chain scission and transfer reactions. The formation of a large proportion of residue implies that crosslinking reactions play an important part in the degradation.
Hand dug well water remains the major source of domestic (drinking) water in the city of Wukari. This study was aimed at the assessment of heavy metal concentration in hand dug well water from four land uses of abattoir (A), waste dump site (B), residential (C) and commercial (D) in Wukari Town, Wukari, Taraba State. There are about 76 hand dug wells in the study area and for the purpose of this study. Yamane (1967) sample size technique was adopted. Based on this, 95% confidence level and an error limit of 5% were adopted. Thus, four (4) For now, it can be concluded that hand dug well water in Wukari Town is fit for domestic use, but that efforts should be made to reduce the magnesium and manganese concentration by having control on the anthropogenic factors that lead to such high concentration levels or else, soon this source of water may become unfit for domestic use. It was recommended that aggressive public awareness and enlightenment on possible impacts of hand dug well water pollution from human activities should be embarked upon by relevant agencies.
K. T. Oyatayo et al.2
Abstract:The synergistic enforcement of the hydrographic behaviors of Kereke and Ukoghor river basins on the river Benue have been identified as the major contributors of the replete episodic flood hazard of Makurdi town. It is on this note that this study aims at analysing and comparing two categories of morphometric parameters; areal and linear/relief which influence runoff/discharge volumes and time lag of Kereke and Ukoghor river basins hydrograpghs respectively. This analysis provides a better understanding of their hydrographic characteristics and vulnerability to the flood hazard. The potential hydrographic variables examined include: runoff, peak flow, time to peak, infiltration, and overland flow. This was achieved using topographical maps of Makurdi sheet 251 NW and 251 SW on scale 1:50,000 published by Federal Survey of Nigeria (1965). These morphometric parameters were evaluated using ArcGIS 10.
This study was aimed at monitoring, mapping and characterisation of floodplain encroachment patterns on the River Kaduna floodplain in Kaduna metropolis, Nigeria,as part of the approach to flood hazard evaluation, flood risk assessment and effective flood and floodplain management. A Topomap of 1967 was used to extract the base built-up layer, while Landsat.TM, 1987, Spot.XS, 1995, Landsat.ETM, 2001 and Quickbird, 2006 were used to generate other built-up layers, which were extracted by digitization and converted to polygon shape files and later used for overlay analysis. A Digital Elevation Map (DEM) of the area was used for delineation of floodplain boundary. ArcGIS sorfware 9.0 operational tools was highly robust and flexible for mapping and analysis of urban growth patterns and characterisation of floodplain encroachment by communities. From the results, it was observed that the highest extents and rates of encroachment are recorded by communities in the proximity of the Central Business District (CBD) such as T/Wada, Ung. Rimi, Barnawa, Doka and the industrial layouts of Kakuri and Kudenda. These areas are the centers of highest socio-economic infrastructure which implies greater flood risk and damage potential in the event of flooding. Results also showed that about 52.83% of the urban segment of the River Kaduna total floodplain area of 48.55km2, has been encroached by built-up. As a result of this pattern of encroachment, strong institutional framework and investment towards effective floodplain management is recommended
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