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.

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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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Flooding is now an annual occurring event in Donga Town especially after heavy rainstorm which is further worsened by the nature of the topography of the area. The knowledge of how the public view flooding is considered a crucial aspect in modern flood management as it steers the development of effective and efficient flood mitigation strategies. This study therefore assessed public perception of flooding in Donga town. Two wards were purposively drawn out of ten wards (Gata Aure and Fada ward). The survey design method was employed in this study. Yamane (1967) method of sample size determination was used to arrive at a sample size of 130 for the study. Systematic random sampling was used in the administration of 130 questionnaires to respondents. Non parametric statistics of Spear Man rank correlation and descriptive statistics (percentages, tables, pie and bar charts) were used to analyze the data. The result of the findings showed that 95% of the respondents were male, 88.4% of the respondents were aware that the area was prone to flooding. Also, about 46.2% perceived that rainfall was the major cause of flooding in the study area. Correlation analysis result was insignificant which implied that in Donga town, educational level of respondents did not influence respondent's awareness level of flooding and that people's perception of flooding was influenced by factors other than respondent's literacy level. The conclusion from the study is that rainfall intensity and amount is the main cause of flooding in Donga town and also individual's response to flooding in the study area is poor. This study recommends the need to educate the people living in the flood plain on the dangers of continuous occupation of the area.

This study aims at using quantitative indices as an improved approach to characterize, analyze and explain urban sprawling beyond the traditional spatial or cartographic mapping and monitoring method which lacks the effectiveness to analyze and explain the details of temporal, horizontal and vertical dimensions of these urban sprawling. In this study, eight (8) indices; Built-up Change Intensity Index (T i ), Built-up Dynamic Index (K i ), Built-up Rate of growth (L), Sprawling Index (S i ), Net Urban Density Index (D 1 ), Marginal Density Index (D 2 ), and Fragmentation Index (F 1 ). These indices were based on three measures of urban growth parameters; measures based on land conversion, density trends and metropolitan form. These quantitative values computed were then interpreted infer if these urban growth patterns could be regarded as sprawling as well as to check for the rate and magnitude of sprawling and thus the environmental and socio-economic implications of these for the study area. RS/GIS methods facilitated achievement of results using cartographic modeling of urban spatial growth which provided estimates used for computation of indices under review. Results revealed that Built-up Change Intensity Index (T i ) has a gradual increasing trend from 7. 8% between 1967 and 1987 to 11.88% between 2001 and 2009. On the other hand both Built-up Dynamic Index (K i ) and Rate of Growth (L) showed declining trend from 24.89 and 1.01% to 18.04 and 0.53% respectively between 1967/87 and 2001/2009. Deductions from all the indices used indicated that the growth patterns of Kaduna Metropolis cannot be significantly regarded as sprawling. Kaduna metropolis is a combination of traditional and modern city with compact built-up, even though it is surrounded with medium developments along its ribbon-like transportation routes including the Kaduna-Kachia, Kaduna-Abuja, to the south, Kaduna-Birnin Gwari and Kaduna-Zaria, to the north and along the Western-Bye pass and recently Eastern-Bye pass under construction.