Joshua Owoseni, PhD | University of Cape Town (original) (raw)

Papers by Joshua Owoseni, PhD

Journal of Sustainable Technology, 2016

Multivariate factor analysis (FA) by principal components reduction and varimax rotation techniqu... more Multivariate factor analysis (FA) by principal components reduction and varimax rotation techniques were employed to reduce bulk hydrogeochemical data from Iju Community, Southwestern Nigeria into components that explain possible underlying structures existing among the variables. This is with a view to characterizing groundwater chemical facies in relation to underlying hydrogeochemical processes suppossed to be responsible for any variation in water quality. Thirteen water quality variables were investigated at 38 sampling points. The data obtained were standardized to ensure normal distribution and then subjected to factor analysis by principal component extraction method with varimax rotation and Kaiser normalization. The criterion of eigenvalues greater than 1.0 and indications from the scree plot informed the extraction of two components which together explain 83.73 % of the total variance in the dataset. Component 1 with high loadings of TDS, EC, Temperature, Total hardness, ...

Some residual lateritic soils derived from crystalline basement complex rocks of south-western Ni... more Some residual lateritic soils derived from crystalline basement complex rocks of south-western Nigeria were investigated for some geotechnical properties to ascertaining their suitability as mineral seals in sanitary landfills. Investigative tests include specific gravity, grain size analysis, consistency limits, compaction, permeability and unconfined compression. The liquid limit, plastic limit and plasticity index (PI) values varied from 32.3 to 41 %, 19.2 to 21.3 % and 12.2 to 20.3 % respectively. Casagrande chart indicated inorganic clayey soils with low to medium plasticity. The computed clay activity ranged from 0.58 to 0.84 (Samples A, B and D) and 1.39 (Sample C), indicating Illite and Smectite as constituent clay minerals in the soils respectively. The PI values (12.2 to 20.3 %) implied that the soils will exhibit low to medium swelling potential when wet. The Maximum Dry Density (MDD) and Optimum Moisture Content (OMC) values ranged from 1.67 to 2.01 g/cm 3 and 12.9 to 22...

African Journal of Science and Technology, 2012

Bivariate correlation and regression techniques were employed to evaluate the relationship betwee... more Bivariate correlation and regression techniques were employed to evaluate the relationship between pairs of geotechnical variables for residual lateritic soils derived from three genetic crystalline rocks in Ibadan metropolis, south-western Nigeria. The significance of mean group differences (parent-rock and level of compactive effort) at 5% level of significance was determined using paired t-test analysis. This is with a view to ascertaining the influence of the pedogenic factor of parent rock, percentage fines, and energy of compaction on engineering index properties of the lateritic soils. The clay-size contents had positive correlations with both Optimum Moisture Content (OMC) and plasticity index, and a negative correlation with the Maximum Dry Density (MDD). The MDD and OMC had significant negative and positive correlations respectively with the amount of fines. The amount of fines and Unconfined Compressive Strength (UCS) had significant negative and positive correlations res...

Integrated multivariate statistical, spatial, and graphical methods were applied to some hydroche... more Integrated multivariate statistical, spatial, and graphical methods were applied to some hydrochemical data in Shagari area, Akure, southwestern Nigeria with a view to elucidating groundwater hydrochemical evolution. Water samples from 23 dug wells were clustered into distinct groups by hierarchical cluster analysis to depict different hydrochemical facies. Factor analysis reduced bulk hydrochemical data to principal components explaining possible dominant processes controlling water chemistry. Three factors which together explain 83.48 % of the total variance in the dataset were retained and interpreted. Factor 1 explains 35.82 % of the total variance and indicates atmospheric controls and silicate mineral weathering processes. Factor 2 explains 35.41 % of the total variance and reflects atmospheric controls, acid rain and speciation reactions producing inorganic carbon ions in solution. Factor 3 explains 12.24 % of the total variance, indicating silicate mineral weathering process...

International Journal of Scientific and Technological Research, 2019

Multivariate statistics was applied to some hydrochemical data from Benin Formation in Benin-city... more Multivariate statistics was applied to some hydrochemical data from Benin Formation in Benin-city metropolis, Southern Nigeria with a view to characterizing and determining the main structures underlying groundwater chemistry in the area. Laboratory chemical analysis followed standard laboratory analytical procedures stipulated by American Society for Testing and Materials (ASTM). Hydrochemical data were standardized to z-scores and screened for outliers, normality and linearity prior to statistical analysis at significant level of 5%. Q-mode Hierarchical Cluster Analysis (HCA) grouped the groundwater samples into distinct clusters to represent different hydrochemical facies. R-mode Principal Component analysis (PCA) reduced bulk hydrochemical data to discrete principal components indicating possible dominant processes responsible for groundwater chemistry. Results of PCA revealed six principal components (PCs) which together explain 86.84 % of the total variance in the dataset. The...

Sustainable Geoscience and Geotourism

Failure of highway pavement and collapse of building in basement complex of Nigeria is often rela... more Failure of highway pavement and collapse of building in basement complex of Nigeria is often related to the instability of the residual. This study evaluated the strength characteristics of gneiss-derived residual Soils as materials usable for road pavement structures. A total of eleven soil samples derived from granite gneiss were subjected to laboratory geotechnical analyses based on standard practices. The geotechnical analyses reveal the soils’ natural moisture content, specific gravity, grain sizes, consistency limits, shearing strengths, maximum dry density, and optimum moisture content. Based on AASHTO classification, the soil samples are classified as A-7-6, A-6, and A-7-5. The results of the laboratory analyses revealed that the natural moisture content and specific gravity ranged from 8.30 to 22.70% and 2.6 to 2.8 respectively. Particle size analysis reveals that the coarse contents of the soils ranged from 28.8% to 59.8% and amount of fines ranged from 40.2 to 71.2%. The ...

Three residual lateritic soils treated with dissolved alum were subjected to investigative labora... more Three residual lateritic soils treated with dissolved alum were subjected to investigative laboratory tests to determine the effects of alum on the engineering performance of the soils developed on genetically different lithological units for optimized use in highway embankment and pavement construction. The geotechnical tests conducted on the three residual lateritic soils treated with dissolved alum contents of 5, 10, 15g/l followed the procedures outlined in the British Standards (BS) 1377. The addition of alum reduced the plasticity with strong negative correlations (-0.95, -0.77 and -0.92) between alum content and Plasticity Index for Oke-Aro gneiss-, Oba-Ile granite-, and Ire-Akari charnockite-derived soils respectively. The California bearing ratio (CBR) and shear strengths also improved with strong positive correlations between alum and CBR (0.98 and 0.86), and between alum and shear strengths (0.94 and 0.65) for granite-and charnockite-derived soils respectively. However, n...

Lack of established waste disposal sites in most parts of Nigeria often results in indiscriminate... more Lack of established waste disposal sites in most parts of Nigeria often results in indiscriminate disposal of wastes and its attending adverse effects on the environment, especially on groundwater resources. The hydrostratigraphy and groundwater vulnerability of Benin-City and environs have been studied. This study employed integrated field-scale studies and GIS-based analyses of borehole data to enhance the understanding of groundwater flow and transport systems in Benin-City and environs, southwestern Nigeria. This is with a view to elucidating groundwater vulnerability to leachate pollution. Nine burrow pit exposures were studied and eight waste disposal sites were located. Fifty-eight borehole logs from this area were analysed. Well correlation and geologic cross-sectioning of the subsurface geology culminated in hydrostratigraphic model, and determination of saturated thickness and lateral extent of aquiferous units. GIS-based contour maps of ground surface elevation, water tab...

This paper presents the use of an 'agricultural waste' in efficient and cost effective so... more This paper presents the use of an 'agricultural waste' in efficient and cost effective soil stabilization based on investigative laboratory tests conducted on residual soils from parts of southwestern Nigeria. The soils were treated with rice-husk ash (RHA) with a view to determining the effects on the engineering performance of the genetically different soils as road construction materials. Index and engineering tests followed the specifications in the British Standard, 1377 with necessary modifications. Laboratory results show appreciable lowering of plasticity indices of the soils, indicating reduced swelling potential which translates to increased soil strength. Moreover, California bearing ratio and shear strength characteristics also improved, with strong positive correlations. The optimum moisture contents drastically reduced, and maximum dry densities escalated. It's quite obvious that RHA improved the engineering geological properties of the soils remarkably. Co...

Environmental Monitoring and Assessment, 2014

Delineating areas susceptible to contamination from anthropogenic sources form an important compo... more Delineating areas susceptible to contamination from anthropogenic sources form an important component of sustainable management of groundwater resources. The present research aims at estimating vulnerability of groundwater by application of DRASTIC and Pesticide DRASTIC models in the southern part of the Gangetic plains in the state of Bihar. The DRASTIC and Pesticide DRASTIC models have considered seven parameters viz. depth to water level, net recharge, aquifer material, soil material, topography, impact of vadose zone and hydraulic conductivity. A third model, Pesticide DRASTIC LU has been adopted by adding land use as an additional parameter, to assess its impact on vulnerability zonation. The DRASTIC model indicated two vulnerable categories, moderate and high, while the Pesticide DRASTIC model revealed moderate, high and very high vulnerable categories. Out of the parameters used, depth to water level affected the vulnerability most. The parameter caused least impact was topography in DRASTIC, while in case of Pesticide DRASTIC and Pesticide DRASTIC LU models, the parameter was hydraulic conductivity. A linear regression between groundwater NO3 concentrations and the vulnerability zonation revealed better correlation for Pesticide DRASTIC model, emphasising the effectiveness of the model in assessing groundwater vulnerability in the study region. Considering all three models, the most vulnerable areas were found to be concentrated mainly in two zones, (i) in the south-western part along Ekangarsarai-Islampur patch and (ii) around Biharsharif-Nagarnausa area in the central part. Both zones were characterised by intensive vegetable cultivation with urban areas in between.

Federal University of Technology Book of Readings, Sep 1, 2014