Ife Journal of Science

Petrochemistry of Charnockitic Rocks of Awo-Osuntedo Area, southwestern Nigeria

2023-08-31T09:23:01+00:00

The petrochemistry of charnockitic rocks from the Awo-Osuntedo area of southwestern Nigeria were investigated with the objectives of presenting their petrogenesis and geotectonic setting at the time of their emplacement. The rocks were mainly found within the migmatitic gneiss country rock and associated pegmatites. They occurred as small intrusive bodies and are composed mainly of orthopyroxene, clinopyroxene, quartz, biotite, secondary amphibole, plagioclase and alkaline feldspars with a small compositional range between basic and intermediate respectively for Awo and Osuntedo rocks. The small Eu* anomalies (0.9-1.47) with an average of 1.2 combined with elemental signatures indicate that the rocks were derived from an enriched mantle with some crustal contamination and emplaced in an environment similar to the arc region of tectonic setting. Though, the rocks have dry mineral assemblages, there is no geochemical evidence to suggest they were derived from melting that was associated with granulite facies metamorphism rather the small sizes of the plutons and the geochemical signatures particularly high magnesian and calc-alkaline nature are typical of the Caledonian type charnockite formed during delamination of thickened continental crust after collisional orogeny.

Dye-Sensitized Solar Cells (DSSCS): The History and a new optical activity-based method to predict the power conversion efficiency

2023-08-31T09:30:22+00:00

Improvement on the performance of dye-sensitized solar cells (DSSCs) has been a major research topic for the past thirty years. Several research efforts on increasing the efficiency of DSSC have mainly focused on the synthesis of novel sensitizers, with the continuous employment of the traditional mesoporous TiO films as 2 - - semiconductor, and the iodide/triiodide (I /I ) electrolyte as redox couple. Since not so much have been done in 3 - - exploring other mesoporous semiconductors and redox electrolytes beyond these two, TiO and I /I couple, 2 3 this paper concisely chronicles the power conversion efficiencies (PCEs) of DSSCs of different dye sensitizers, where only TiO nanofilm and iodide/triiodide redox couple have been used as the semiconductor and 2 electrolyte systems respectively. This list was used to obtain possible relationship between the optical properties of dyes and the PCE of the DSSC. Dye sensitizers with PCE values > 1.00% were employed. The spectral properties of each of the selected sensitizers were used to obtain their spectrum power, I(l). An increase in PCE value as I(l) increases was observed for 81.25% of the sixteen sensitizers considered, which suggests that a direct correlation could exist between the I(l) of a sensitizer and the PCE of the DSSC of that sensitizer.

Geochemical elements as provenance and paleoenvironmental indicators in siliciclastic sediments of Neogene Gwandu formation exposed in Birnin Kebbi Area, Northwestern Nigeria

2023-08-31T09:43:00+00:00

Sediments from the exposed Gwandu Formation in Birnin Kebbi area (Northwest Nigeria) were analysed for their geochemical composition in order to determine their provenance, and paleoenvironments of deposition. Inductively Coupled plasma -mass spectrometer (ICP-MS) and -emission spectrometer (ICP-ES) were used for trace and major elements quantification. Also, samples were subjected to X-ray diffractometric analysis for the determination of their mineralogical constituents, and total sulphur (TOS) and total organic carbon (TOC) were determined using LECO analysis. High intensity of chemical weathering was inferred, as calculated values for chemical index of alteration (CIA), plagioclase index of alteration (PIA) and chemical index of weathering (CIW) were all above 90. Quartz, kaolinite, hematite and rutile in relative order of decreasing abundance, are the mineral constituents of the sediments. Bivariate plot of Fe₂O_3T vs MgO and the ternary diagram of MgO- Fe₂O_{3T –}SiO₂ /Al₂O₃ revealed that sediments were sourced from non-marine and deltaic environments. High LREE/HREE ratios indicate relative depletion in the heavy rare earth elements (HREE), and with all values of europium anomaly below unity, it is logical to infer that sediments are predominantly constituted by felsic materials. Bivariate plot of TiO₂ vs Zr showed that approximately 93 % of the samples are dominantly felsic 2 constituents. Also, ratios of Cr/V, Y/Ni, Th/U and the scatter plot of Th-Sc have suggested that sediments are constituted substantially by Upper continental crustal materials, and predominance of lower continental crustal components in few cases. The ratios of TOC/S suggested non-marine to marginal marine environments of deposition. Whereas, U/Th ratios implied oxic paleoenvironment for all strata, the V/Cr ratios inferred 71.43 % of the strata from Gwandu Formation were emplaced under oxidizing condition. Conversely, V/Sc ratios revealed that 78.57 % of the samples are from strata emplaced in oxygen depleted environment. Inferring from the various provenance indices, sediments of Gwandu Formation composed dominantly of materials from the upper continental crust, and low but considerable proportion from lower continental crust. Also, the application of ratios of redox sensitive elements has unveiled that sediments were emplaced principally under oxic conditions.

Analysis of elastic scattering cross sections of ¹⁶”O ²⁷ON” Al and ¹⁵⁴Sm using the semi-microscopic double folding model

2023-08-31T10:15:19+00:00

The elastic scattering data for¹⁶ O +²⁷ Al at a laboratory energy (ELab ) of 134 MeV and¹⁶ O +¹⁵⁴ Sm at E_Lab = 85 and 134 MeV were analyzed using the optical model-based double-folding model. The real component of the optical model potential was generated from the microscopic double-folding (DF) model, while the imaginary part was considered using both microscopic and Woods-Saxon phenomenological forms. Two density-independent effective nucleon-nucleon (NN) interactions were considered in the DF procedure: the Michigan-3-Yukawa (M3Y) and Knyazkov and Hefter (KH). The folded potential was constructed using Two-parameter Fermi (2pF) density distribution for the target nuclei and three different forms of projectile density: Two-parameter Fermi (2pF), Slater determinants consisting of harmonic oscillator single-particle wave functions (SDHO), and DiracHartree-Bogoliubov (DHB) density distributions. The SDHO density exhibited slightly better agreement with the data than 2pF and DHB. The results obtained using the KH interaction were highly consistent with those achieved with the M3Y interaction. In general, the DF model-based calculations compared reasonably well with the experimental data.

Evaluation of trace elements in the sediments of intertidal zone around Mahin-Ugbo Area, southwestern Nigeria

2023-08-31T10:45:30+00:00

This study assessed the spatial distribution of Trace Elements (TE) in the muddy sediments of the Mahin-Ugbo coastal area of Southwestern Nigeria, using Inductively Coupled Plasma-mass spectrometry, (ICP-MS). The physicochemical parameters (pH, EC and TDS) of the sediments were also determined. Results showed that the mean values for pH, E.C and TDS were 5.09, 153.6 μs/cm and 76.8 mg/L, respectively. Further, there was a varying distribution pattern of TE concentrations: Mn> Zn > Ba > Cr > V > Sr > Pb > La > Cu > Ni > Co > As > Th > Sc > Ga. The As, Pb, and Zn concentrations in the sediment with mean values of 11.2, 40.4 and 122.1 ppm, respectively, were significantly higher than the average concentrations of As (10 ppm), Pb (20 ppm) and Zn (90 ppm) in natural shale, suggesting anthropogenic TE enrichment in the study area. To corroborate this, the TE source apportionments in the sediments using correlation coefficient, bi-variant plots and principal component analyses showed that the TE enrichment may have been anthropogenically induced. Pollution status assessments using I-geo, contamination factors and pollution load index indicated that the study area's sediments is slightly to moderately polluted. These findings suggest that although the area is not heavily polluted, increasing human activities, from inland rivers to the coastal area, in the study area will in no time be a cause for concern.

Exploring the geometry of miniaturized Archimedean SPIRAL Antennas for small and portable multitask devices

2023-08-31T10:58:15+00:00

The focus of miniaturization is the production of small and portable devices that can be carried in the pocket anywhere and anytime. Small and portable devices that perform multitask such the smartphone requires a portable and efficient antenna that operates in many frequency bands. A single planar miniaturized Archimedean spiral antenna, which operates in a frequency range that is determined by its inner and outer radii of its arc, has been adjourned to be a better candidate for these multiple tasks. This study examined the geometry of a miniaturized Archimedean spiral antenna of varying turns. An inner radius of 4.90 mm and a thickness of 0.0356 mm suitable for the printed antenna were previously chosen for the study. The length of the arc and the outer radius were determined for spiral turns ranging from 0.5 to 100 with an incremental step of 0.5. Results revealed the radial distance generating the spiral, the length of its arc, the outer radius, and the surface area were 4.97 mm, 2 15.51 mm, 4.97 mm and 77.16 mm for 0.5 spiral turns, and 19.12 mm, 7,546.80 mm, 2,849.33 mm and 1,148.64 2 mm for 100 spiral turns. Based on the outer radii, the frequency range of operation will be between 16.76 MHz and 9.60 GHz. The mathematical functions formulated through curve fitting described the relationship between the outer radius and arc length with a power function and the number of turns and frequency with an exponential function, while arc length and radial distance, area and number of turns, and area and pitch angle are described by polynomial functions. It is recommended that further analysis on the geometry of the minimized Archimedean spiral antenna be conducted.

Revised stratigraphic sequence and type sections of the Southern Bida Basin, Nigeria

2023-08-31T11:17:54+00:00

A reassessment of the stratigraphy of the Southern Bida Basin has been attempted among various disagreements. For this work, field geological mapping and stratigraphic descriptions of exposed lithologic types on outcrop sections were used. Section-by-section descriptions of important outcrops based on field observations aided in identifying lithologic units and delineating the boundaries of the sub-basin's three formations (Lokoja, Ahoko, and Agbaja). The type sections for formations in the sub-basin were not properly erected, so Jones (1958) type section has been supplemented by a more comprehensive hypostratotype, and the name Patti Formation, which is considered a misnomer in this context, has been replaced with Ahoko Formation proposed by Rahaman et al. (2019). Ahoko village is the type locality. The Agbaja Plateau, where the Agbaja Formation is best exposed, has been presented as the lectostratotype for the formation, while the revised stratigraphic succession of the Lokoja region shows the Lokoja Formation directly encompassing the Paleozoic Basement terrain, with the Maastrichtian Agbaja and Ahoko Formations (former Patti) overlying it sequentially.

Synthesis, characterization and in-silico studies of (e)-4-[(4,5- dimethylthiazol-2-yl)diazenyl]-2-isopropyl-5-methylphenol and its coordination compounds

2023-08-31T12:02:48+00:00

An azo dye, (E)-4-((4,5-dimethylthiazol-2-yl)diazenyl)-2-isopropyl-5-methylphenol (L1), was prepared by the reaction of 5-methyl- 2-(propan-2-yl)phenol with the diazonium salt of 2-amino-4,5-dimethylthiazole. Characterization was carried out using proton and carbon-13 nuclear magnetic resonance spectroscopy. Coordination compounds of L1 with Mn(III), Fe(III) and Co(III) in a 1:2 metal to ligand mole ratio were subsequently synthesized. Corresponding mixed ligand complexes were also synthesized using 2- hydroxybenzoic acid (L2) as the secondary ligand. The coordination compounds were characterized by electronic and infrared spectrophotoscopy, magnetic susceptibility measurements, and percent metal composition. Subsequently, in silicostudies were performed based on the proposed structures of the synthesized compounds to determine their binding affinity and binding site with calf thymus DNA. The results obtained showed that all complexes achieved octahedral geometry. The results also showed that some of the compounds had better affinity for CT-DNA than the standard.

Hydrocarbon detection and depositional environment prognosis in the Niger Delta - Integrated insights from log and seismic avo-inversion attributes

2023-08-31T12:16:56+00:00

This study demonstrates the effectiveness of integrated seismic analysis and petrophysically constrained AVOinversion for reservoir evaluation and assessment of hydrocarbon potential and depositional environment in the Niger Delta. It is aimed at improved prediction of reservoir fluid, lithology, and ultimately the hydrocarbon prospects, with reduced uncertainties. The results delineate the characteristics of the reservoir sands, highlight major facies heterogeneities, unravel prolific stratigraphic features (such as channels, fan lobes), depositional fairways and provide insight into the mapped geology. These are expected to consequently reduce the uncertainties associated with the prospects for economic decision making.

Estimation of ground depth of radioelements sources in Ogun State, Southwestern Nigeria using gradient techniques

2023-08-31T12:35:08+00:00

Radioelement exploration has gained economic interest recently due to its usefulness in the detection and delineation of mineral deposits. In this study, the airborne radiometric data were analysed for depth estimation of the radioelement deposit in Ogun state, Nigeria. Three enhancement gradient techniques, namely; Analytical Signal Amplitude (ASA), Horizontal Gradient Magnitude (HGM) and Local Wave Number (LWN) were employed to estimate the possible depth of radioelements for mineralization. Geosoft's (Oasis Montaj) software and Potential Field's (PF) software were used to conduct the estimations. The result obtained revealed shallow sources of 0.584 km (LWN) and 0.387 km (ASA), and deep-seated sources of 5.950 km (ASA) and 5.880 km (ASA) for uranium and thorium, respectively. The shallow source and deep source for potassium are 0.259 km (ASA) and 2.540 km (ASA), respectively. In this study, the position and depth of the source were automatically estimated using linear equations based on derivatives without the use of any a priori knowledge. The three gradient methods are therefore found suitable in estimating the depth to radioelement anomalous source.