Accurate measurement of heat flux is essential to optimize structural and process design and to improve understanding of energy transfer in natural systems. Laboratory and field experiments evaluated the performance of a new, perforated heat flux plate designed to reduce flow distortion for environmental applications. Laboratory tests involving dry and saturated sand showed that performance of the new CAPTEC plate is comparable to a solid, standard REBS plate. Very low thermal gradients may have however led to poor performance of the CAPTEC plate in saturated sand. Water infiltration and redistribution experiments using clayey and sandy soils showed an apparent reduced disruption of liquid water and vapour in the soil surrounding the CAPTEC plate as compared to solid Hukseflux and standard REBS plates. Surface area of REBS plate, though smaller than that of CAPTEC, did not lead to any significantly improved evaporation, due to perforations on CAPTEC plate. Field tests in a loam soil indicated that the CAPTEC plates were durable and produced daily total flux values within ~ 0.15 MJ m − 2 of independent estimates. Accurate measurement of heat flux is essential to optimize structural and process design and to improve understanding of energy transfer in natural systems. Laboratory and field experiments evaluated the performance of a new, perforated heat flux plate designed to reduce flow distortion for environmental applications. Laboratory tests involving dry and saturated sand showed that performance of the new CAPTEC plate is comparable to a solid, standard REBS plate. Very low thermal gradients may have however led to poor performance of the CAPTEC plate in saturated sand. Water infiltration and redistribution experiments using clayey and sandy soils showed an apparent reduced disruption of liquid water and vapour in the soil surrounding the CAPTEC plate as compared to solid Hukseflux and standard REBS plates. Surface area of REBS plate, though smaller than that of CAPTEC, did not lead to any significantly improved evaporation, due to perforations on CAPTEC plate. Field tests in a loam soil indicated that the CAPTEC plates were durable and produced daily total flux values within~0.15 MJ m − 2 of independent estimates.

Hydrochemical investigation of groundwater was carried out on the coastal aquifers of Ogun Waterside, Southwestern Nigeria. Groundwater samples were collected and assayed for physicochemical parameters during wet season (August, 2016) and dry season (March, 2017). The analysed data were further subjected to correlation analysis (CA), principal component analysis (PCA), hydrochemical facies and descriptive statistics. Results revealed that the groundwater is slightly acidic with fresh to saline character. The CA showed very strong associations between TDS, EC and Cl concentrations in both wet and dry seasons. PCA confirmed the main factor influencing the groundwater chemistry in the study area to be component I (salinity component). Piper plots also revealed that the aquifer is mainly of water type. Schoeller and Stiff diagrams showed that the groundwater comprises relative abundance of major ions in the following order: for the cations and for the anions. Thus, the primary process influencing the hydrochemistry of the study area is saltwater invasion while mineral dissolution and rainwater infiltration play less significant roles. Most parameters fall within the permissible limit proposed by the World Health Organization (2011) and Nigerian Standard for Drinking Water Quality (2007). However, higher concentrations of chloride and bicarbonate ions observed towards the southern flank of the study area suggest signs of impairment. Assessment of the sampled water for agricultural purposes with respect to salinity hazard, Total Hardness (TH), percentage sodium (%Na) and Sodium Adsorption Ratio (SAR) revealed that the water is suitable for agricultural activities.

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A magnetic survey of Ibadan area in the South-Western part of Nigeria was performed as part of the largest airborne geophysical survey blocks flown between 2003 and 2010 by the Nigeria Geological Survey Agency. Two magnetic data enhancement procedures were employed to determine their effectiveness in characterizing the study area. The upward continuation together with reduction to Pole technique significantly improve the interpretation of magnetic data in terms of discriminating between shallow and deep magnetic sources within the study area.

Geological structures are 3-Dimensional (3D) in nature, thus 1-Dimensional and 2-Dimensional surveys cannot adequately model them. However, sophisticated 3D survey equipment are very expensive. In this study, a single-channel ABEM SAS 300B Terrameter was used to obtain 3D models of the subsurface. This survey was carried out at three different locations within Abeokuta, a basement complex terrain of southwestern Nigeria. The area falls within longitudes 3.35° and 3.38° East and latitudes 7.22° and 7.46° North respectively, with coordinates of 2550.0 m North and 1724.2 m East. A manual 4-electrode system was used in the Electrical Resistivity Tomography survey at the three locations. Each location was marked into 7 by 7 square grids with 1 m, 3 m and 5 m unit electrode spacings in succession. The pole-pole array was used with the two remote electrodes placed at distances of 23 m, 40 m and 65 m from the grids of 1 m, 3 m and 5 m unit electrode spacings respectively, to reduce their telluric effects on the measured apparent resistivity values. To reduce survey time consumption, the cross-diagonal survey method was adopted. The data obtained were analysed using a 3D inversion software called RES3DINV and 3-Dimensional models of the subsurface were also generated using Slicer Dicer graphics software. The study revealed layers extending to depths of 7.75 m, 23.2 m and 38.7 m for unit electrode spacings of 1 m, 3 m and 5 m respectively. It revealed resistivity values ranging from 7.3 Ωm to 300 Ωm for electrode spacing of 1.0 m; 13.8 Ωm to 200 Ωm for electrode spacing of 3 m and 3.9 Ωm to 200 Ωm for electrode spacing of 5 m at the first location. At the second location, it revealed resistivity values ranging from 0.53 Ωm to 120.0 Ωm for electrode spacing of 3 m and 0.30 Ωm to 100 Ωm for electrode spacing of 5 m. For electrode spacings of 1 m, 3 m and 5 m, resistivity values ranging from 6.1 Ωm to 600 Ωm, 12 Ωm to 600 Ωm and 0.85 Ωm to 1700 Ωm were obtained respectively at the third location. Generally, this study revealed lithologies composed of lateritic soil, sand, sandstone, sandyclay, clayeysand, weathered rock, fractured rock, clay and fresh basement; to a depth of about 39 m. Also, location 3 was discovered to have good groundwater prospects; though not as good as for locations 1 and 2.