53 research outputs found
Plasticity and Compressibility Characteristics of Lateritic Soil From Southwestern Nigeria
Plasticity index and coefficient of compressibility amongst other characteristics were determined for some lateritic soil samples of Southwestern Nigeria with a view to establishing the relationship between their plasticity and compressibility as well as predicting their in-situ compressibility and also determine the effect of the parent rocks on the plasticity and compressibility. Two study areas were chosen in Ibadan, Southwestern Nigeria where ten disturbed and ten undisturbed samples each were collected. The disturbed samples were subjected to a number of geotechnical tests: grain size, distribution analysis, specific grant and consistency test. The undisturbed samples were subjected to consolidation test. The study revealed the rock type in study area A to be quartzschist and area B to be granitic. The specific gravity of the soil grains ranged between 2.48 and 2.72; while the plasticity index value was between 9.7 and 21.4%. Coefficient of consolidation ranged between 29.39mm2/min and 32.56mm2/mm with coefficient of volume compressibility between 1.08 x10-3 m2/KN and 1.94 x10-3m2/KN. The soil samples were generally well-graded reddish brown, sandy-silt-clay of medium plasticity and compressibility with dominant kaoline clay mineral in the quartzschist derived soil while the dominant clay mineral in the granite derived soil is illite. The most influenced parameter of the parent rocks was the coefficient of compressibility, which revealed the samples of the two study areas to be suitable for construction work as well as landfill site with little compaction.  
Integrated Geophysical Mapping to Determine Depth to Basement at Awa Ijebu, Southwestern Nigeria
Integrated surface electrical resistivity, magnetic survey and horizontal profiling were conducted at Awa Ijebu, South-western Nigeria, to delineate the probable depth of basement and determine geological anomalies therein. Wenner resistivity profiling and magnetic data were acquired at intervals of 5.0m along four traverses of 100.0m long and five traverses of 250.0m long respectively. The resistivity data obtained revealed three subsurface geologic layers: top soil, weathered bedrock and intrusive pegmatite rock. The distinct high resistivity zone is interpreted as the intrusive pegmatite rock while the low resistivity zone is interpreted as fault zone. The magnetic survey result revealed that there was a high magnetic anomaly trending Southeast – Northwest direction and dipping westward.  
EXPERIMENTAL INVESTIGATION OF LEACHATE CONTAMINATION ON GROUNDWATER EXPLORATION IN BASEMENT COMPLEX AREA
A total of ten groundwater samples were collected from wells around the site of Orita Aperin refuse dump, Ibadan, Southwest, Nigeria, to determine the extent of groundwater contamination. The results of the hydro-chemical analysis show that groundwater samples collected from wells away from the leachate revealed comparable W.H.O. standard values for groundwater consumption. Most obvious parameters are: increase in total hardness (between 184.8 and 239.6mg/l for samples near the leachate; 74 and 102mg/l for samples far from the leachate), low calcium (ranged from 46.2 to 78.7mg/l for samples near the leachate; 3.7 to 32.8mg/l for samples far from the leachate), magne- sium (ranged from 5.1 to 30.3mg/l for samples near the leachate; 3.4 to 21.5mg/l for samples far from the leachate), chloride (between 20 and 224mg/l for samples near the leachate, 32 and 174mg/l), and sulphate content (ranged from 9 to 76mg/l for samples near the leachate; 25 to 38mg/l for samples far from the leachate); while high values of TDS (in samples A and C and I), nitrate (in samples A and C) and chloride (in samples A and I) which were due to the effect of leachate on the water quality result- ing to contamination of these wells. Thus, adequate treatment should be carried out on wells located close to the leachate before consumption. 
Delineation of Leachate Plume Migration Using Electrical Resistivity Imaging on Lapite Dumpsite in Ibadan, Southwestern Nigeria
A geophysical investigation involving 2D resistivity survey was carried out on Lapite dump site that has been in operation since 1998 in ancient city of Ibadan, Southwestern Nigeria. The aim was to map the conductive leachate plume and extent of migration of leachate plumes in the subsurface for possible groundwater contamination. The 2D resistivity survey was carried out using Campus Tigre model resistivity meter with Wenner array configuration of electrode spacing distance ranging from 5 - 25m. A total of nine (9) 2D resistivity profiles with length ranging between 80 and 120 m were conducted within the dump site. A control profile of 2D resistivity survey was also carried out at about 300 m away from the dump site. The obtained resistivity data was interpreted using both RES2DINV and RES3DINV respectively. The 2D and 3D inverse resistivity models of the subsurface revealed the extent of leachate plumes with resistivity values less than 10 Ωm and allowed the location of leachate, clay soil, bedrock and seepage path from the dumpsite to be clearly delineated. There may be possible contamination of shallow groundwater system in the nearest future if proper mitigation measures are not taken into consideration at the dumpsit
Assessment of groundwater contamination around active dumpsite in Ibadan southwestern Nigeria using integrated electrical resistivity and hydrochemical methods
Investigation of groundwater contamination
due to leachate migration in a solid waste disposal site was
done using both geophysical and hydrochemical methods.
The main goals were to delineate groundwater contamination
due to leachate percolation and thus assessment of
quality of groundwater from nearby hand-dug wells bordering
the dumpsite for drinking purpose. A total of ten
resistivity traverses were acquired within and outside the
dumpsite using Wenner configuration with constant electrode
separation ranging from 5 to 25 m. The 2D resistivity
data were processed and inverted using RES2DINV and
RES3DINV softwares, respectively. Geochemical assessment
of groundwater samples were carried out according to
APHA standards while hydrochemical facies of the sampled
groundwater was evaluated using Piper Trilinear
software. The inverse resistivity models of the subsurface
from 2D and 3D imaging revealed low resistivity value less
than 10 X m suspected to be leachate while 3D inverse
sections allowed delineation of leachate, weathered layer,
bedrock and seepage path from the dumpsite. The extent of migration was more pronounced in the southern part of the
dumpsite, hence possible contamination of shallow
groundwater system as dumpsite ages. The results of
physico-chemical analyses showed the groundwater samples
to be within the limits of WHO/NSDWQ for drinking
purpose. However, higher values of concentrations of most
analyzed parameters were noticed in well 1 due to its
nearness to dumpsite and well 10 due to agricultural
activities, respectively. Interpretation of Piper diagram
showed CaHCO3 to be dominant facie in the area while
alkaline earth metals (Ca2þ; Mg2þ) and weak acids
(HCO3
-, CO3-) are dominant cations and anions during
both climatic seasons. Groundwater in the study area is of
hard, fresh and alkaline in natur
Investigation of incessant road failure in parts of Abeokuta, Southwestern Nigeria using integrated geoelectric methods and soil analysis
A flexible pavement devoid of discontinuities allows for smooth movement of
a vehicle load on the roadway. This study involved the use of integrated
geoelectric methods comprised of 1D and 2D Electrical Resistivity
Tomography (ERT) as well as soil analysis to investigate causes of unceasing
road failures along busy Camp—Alabata Road, Abeokuta, Southwestern
Nigeria. Four road sections (two failed portions and one fair section and one
good section) were identified along which four resistivity traverses were
established along the investigated roadway. Four 1D Vertical Electrical
Sounding (VES) points were also carried out on the 2D ERT lines. Apparent
resistivity data were measured along the four traverses using Schlumberger
and Wenner arrays with the aid of a Campus Ohmega resistivity meter. The
VES and 2D resistivity data were processed and inverted using WinResist an
Corrosion Inhibition Behaviour for Mild Steel by Extracts of Musa sapientum Peels in HCl Solution: Kinetics and Thermodynamics Study
Staff PublicationThe inhibition of the corrosion of mild steel by acid extract of Musa sapientum peels in 1M HCl was
investigated using weight loss method. The results showed that the corrosion rate of mild steel in 1M HCl
decreases with increase in concentration of the extracts and the values were in the range 0.013021 - 0.002127
ghr-1
cm-2
. The inhibition efficiency increases progressively as the concentration of the extracts increases up to
about 4% (v/v), above which, further increase in extract concentration did not cause any significant change in
the inhibition efficiency. Effects of temperature on the inhibition efficiency of the extracts showed that
inhibition efficiency decreases with increase in temperature. Activation energy (Ea) was found to be 61.60
Kjmol-1
for 1M HCl and increases to 66.72Kjmol-1
in the presence of Musa sapientum extract. The values for
enthalpy of activation and entropy were all positive indicating the endothermic nature of the mild steel
dissolution process. Calculated Gibbs free energy was in the range -9.43 to -8.99KJ. Kinetics of the reaction in
the presence of the extracts revealed that it follows a first order reaction and the half-life increases as the
concentration of the extracts increases suggesting that inhibition efficiency increases with increase in the
concentration of the extracts. Preliminary investigation of the phytochemical constituents showed that Musa
sapientumcontains tannin, flavonoid, terpenoid and some other compounds in trace constituents
Investigation of Sub Soil Corrosion Using Electrical Resistivity Method: Federal University Oye Ekiti Phase II Campus as a case study
Electrical Resistivity survey was carried out with the aim of identifying the degree of soil corrosion associated with the sub soil of the Federal University Oye Ekiti phase II. The sub soil resistivity of the area was surveyed and evaluated using Ohmega resistivity meter. The sub soil resistivity parameters were used to delineate the degree of the sub soil corrosion. Four electrodes were inserted into the soil/rock using the Wenner profiling, vertical electrical sounding and Dipole- Dipole array along the traverses with a spacing of 5m and n =1 to 5.In this method, artificially generated electric current(I) was injected into the ground via two current electrodes while the resulting potential difference (V) is measured by another pair of electrodes. The survey revealed that the Southwest and Northwest regions of the study area were associated with high resistivity (200-500 Ω-m).This implies that the soil structure of the region is not corrosive, while the southeast region was associated with low resistivity (20-80 Ω-m) value which implies that the sub soil structure is corrosive. The degree of corrosion increases from the western to eastern part of the study area which may be due to bedrock topography. Of all the layers investigated, the topsoil layer is highly corrosive compare to other layers
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