Contribution of solar quiet (Sq) daily current variations to the deep earth conductivity within the Southern African Region
November 2023
This work focuses on determining the source current systems by applying the method of spherical harmonic analysis (SHA) to geomagnetic field data obtained from ground measurements. The objectives are to establish the mantle conductivity-depth profile and to compare the results of the profiles from four stations with other research findings. The study utilizes magnetometer data obtained for the year 2011 from geomagnetic...
foF2 diurnal variation at Dakar station during the period of geomagnetic shock of variable duration over solar cycle 21 and 22: Prediction with IRI 2016
November 2023
This work concerns the comparative study of the diurnal variation of the critical frequency of the F2 layer (foF2) between experimental data from the Dakar station and those of the IRI 2016 model through its URSI. The comparison was conducted during solar cycles 21 and 22, across different phases, and on various days of geomagnetic shock activity. The results indicate that during solar minimum, the graphs of the...
Hydrogeological assessment of groundwater resources within Isuikwuato and environ South Eastern Nigeria: Agenda for food agriculture and clean water policies
October 2023
Groundwater resources of the Isuikwuato area, south eastern Nigeria, have been evaluated using integrated geophysical and hydrogeochemical techniques, to determine the quality and usability of the groundwater for domestic and agricultural purposes. Twenty Vertical Electrical Soundings (VES) physicochemical analyses were done. Depth to aquiferous unit varies from 38 to 148 m. The hydrogeochemical characterization shows...
Geo-spatial distribution of radio refractivity and the influence of fade depth on microwave propagation signals over Nigeria
July 2023
The need for more bandwidth for a broad range of purposes necessitates research into how radio refractivity, multipath fading, and geoclimatic variables affect terrestrial and satellite propagation links. In this study, a geographical distribution approach to radio refractivity and fade depth over five locations in Nigeria—Akure, Enugu, Jos, Minna, and Sokoto based on five-year (2017–2021) measured data of...
Rainfall and sea-surface temperature analyses over Maiduguri, Nigeria using Mann-Kendall test
May 2023
Monitoring of rainfall has become necessary, because of the adverse effects of rainfall variability (e.g. floods, drought, poor harvests, etc.) on agriculture as well as economy. This study is geared towards a better understanding of rainfall variability in Maiduguri, an agrarian community, and sea-surface temperature using Mann-Kendall statistical analyses of data for a period of thirty-four years from Nigeria...
A mathematical model development to investigate the impact of key parameters on the generated voltage hysteresis of silicon anode based lithium half cells
March 2023
Lithium-ion batteries are widely used in various energy storage systems. In this article, a physics-based mathematical model of silicon micro-particle (SiMP) anode is developed to identify the principal reasons of voltage hysteresis occurrence during lithiation and delithiation battery cycling of silicon (Si) anode-based lithium half cells. Firstly, lithium diffusion, reaction kinetics, thermodynamics and mechanical...
Mannheim partner curves in the special linear group
March 2023
In this study, we state some basic results about the geometry of the special linear group SL(2,R), seen as a subset of in terms of the left invariant fields, such as bracketing, Levi Civita connection ∇ and Riemann curvature tensor R, we give some basic theorems for Mannheim partner curves in the special linear group. We also find the relations between the curvatures and torsions of these...
Study of diffusion processes in contact areas of thermocouples with metals
March 2023
Diffusion processes on the contact areas of the metal-solder-semiconductor system are experimentally studied in this work. Diffusion coefficients, activation energies and pre-exponential factors in samples commutated with solders based on Pb-Sb are determined. It has been established that lead-based solder has a significantly higher inertness to thermoelectric materials. The nickel-phosphorus coating was coated with a...
Using vertical electrical sounding and 2D resistivity tomography to investigate Osogbo central waste dumpsite, Osun State, Nigeria
February 2023
The Osogbo central solid waste dumpsite in Osun State, Nigeria falls within the Ilesha Schist Belt, southwestern basement complex of Nigeria. Thirty-three (33) Vertical Electric Sounding (VES), and 2-D Electric Resistivity Tomography (ERT) data were acquired across various locations in the study area using ABEM Terrameter SAS 300, respectively. Schlumberger configuration with a maximum spread length of 100 m, for the...
Indoor ionizing radiation measurement in different departments of the Federal University of Technology Owerri
February 2023
The indoor background ionizing radiation of various offices of the various departments in Federal University of Technology, Owerri (FUTO) was estimated in this study. This was conducted using a well calibrated digital Geiger - Muller Counter (GCA - 04W). The highest value measured was 0.0873 ± 0.1432 µSv/h while the lowest value was 0.0006 ± 0.0001 µSv/h with an average value of 0.0052 ±...
Performance comparison of diversity techniques with Addictive White Gaussian Channel (AWGC) in free space optical communication (FSO) under atmospheric turbulence scenario
January 2023
The spatial diversity techniques are broken down and explained systematically along with its combination which includes Maximum Ratio Combining (MRC), Equal Gain Combining (EGC) and Simple Selection Combining (SC) under the influence of atmospheric-induced turbulence fading in Free Space Optical (FSO) communication. Diversity is a technique used to prevent or reduce multipath. Multipath is a phenomenon describing...
Design of a low-cost electronic board for monitoring photovoltaic systems
January 2023
The development of renewable energies is essential to meet the energy demand which is growing year after year. Africa has a strong solar potential which is, however, little exploited. The development of solar photovoltaic (PV) energy will be more favored with the democratization of performance monitoring and characterization tools for PV systems. Monitoring systems are very important because they allow the monitoring of...
Delineation of potential zones of lead-zinc mineralization in Uburu Ohaozara L.G.A South Eastern Nigeria, using electrical resistivity tomography and induced polarization methods
December 2022
An integrated geoelectrical study combining electrical resistivity tomography (ERT) and induced polarization (IP) have been used to delineate potential zones of Lead-Zinc mineralization in Umuobuna, Uburu, Ohaozara local government area, southeastern Nigeria. The wenner array configuration was used to acquire resistivity and induced polarization data sets along three traverses of approximate length of 1 km each and...
Uncooled PV cell under variable light concentration: Determination of profiles of the temperature, the intrinsic properties and the carrier density
December 2022
Studies on concentrated light influence do not take into account the effect of the heating and this proves to be harmful on photovoltaic parameters. The main purpose of this work is to study the effects of light concentration and the heating caused by this concentration on intrinsic properties and carrier density profile. A thermal model of the PV cell is proposed. By applying the power balance at the steady-state, the...
Solution of Einstein's equations, for a fluid and homogeneous star
December 2022
Using the mathematical aspects of the Schwarzschild metric, we present different variables transformation which proves that the central singularity hypothesis does not exist. The geometric interpretation of the black hole from the Schwarzschild metric is not mathematically convincing. The different mathematical approaches taken by many authors were viewed, such as the Painleve metric and its complex variant, and the...
Mineralogical evaluation of clay deposits of Nanka formation in parts of South-eastern Nigeria
November 2022
Detailed field geology and laboratory studies of the Eocene Nanka Formation were carried out where they outcropped in places like Ogbunike, Umunya, Nanka, Ekwulobia and Ogbu all in Anambra State, South-eastern Nigeria to determine their mineralogical composition. Samples of clay and unconsolidated sands were collected from outcrop locations within the formation and subjected to X-ray diffraction and granulometric...
Solar wind and geomagnetic activity during two antagonist solar cycles: Comparative study between the solar cycles 23 and 24
October 2022
To better understand the geomagnetic conditions and the particularities of solar cycles 23 and 24, we present analysis from morphological variations of solar and geomagnetic activities parameters IMF-Bz, the interplanetary electric field (E), the proton density (N), Dst (disturbance storm time), Polar cap (PC) indices (PCN and PCS), and geomagnetic activity index aa. The occurrences of the different classes of...
Combined application of vertical electrical sounding and 2D electrical resistivity tomography for groundwater exploration in parts of Enugu metropolis, Southeastern Nigeria
October 2022
Vertical electrical sounding (VES) and 2D electrical resistivity tomography (ERT) employing the Schlumberger and Wenner configurations respectively were combined for groundwater exploration in parts of Enugu metropolis. The area is underlain by Enugu Shale and Mamu Formation. A total of twenty (20) VES and four (4) 2D ERT traverses were acquired in the study area. VES and 2D ERT data were processed and interpreted using...
Research for fabrication and antibacterial properties of hybrid nanoparticles Ag-MnFe2O4
September 2022
The hybrid nanoparticles Ag-MnFe2O4 was successfully fabricated by the seed-growth method and thermal decomposition method. The shape and size of these nanoparticles were evaluated by Transmission electron microscopes (TEM) images showing that these nanoparticles are quite uniform and have a diameter of about 20 nm. The UV-Vis spectrum of hybrid nanoparticles Ag-MnFe2O4 shows that in the wavelength region from 300 to...
Excitation of 3G° levels of nickel atom by electron impact
September 2022
Excitation of 3G° levels of the nickel atom was investigated using the method of extended atomic and electron crossing beams with registration of the optical signal of excited atoms. At an energy of exciting electrons of 50 eV, 14 excitation cross sections were measured. In the electron energy range of 0 to 200 eV, optical excitation functions (OEF) were recorded for transitions from five levels. Based on the...
2D electrical resistivity imaging of fracture zones in Isu-Awaa, Enugu State, Southeastern Nigeria
August 2022
2D electrical resistivity imaging technique has been used to investigate the nature and dimensions of the fracture prone zones in Isu-Awaa, Enugu State, Nigeria. The study area lies within Latitude 06° 14I 0II N to 06° 17I 0II N and Longitudes 007° 23I 0II E to 007° 28I 0II E, with an area extent of about 51 Km2. The area is underlain by three main geological units (Enugu Shale, Owelli Sandstone and Mamu...
Effect of soaking sample cubes on concrete compressive strength: The case of Ethiopian Construction Industry
February 2022
Concrete is a major component of construction work composed of fine and coarse aggregates bound together with a cement-water solution paste produced with hydration process. Concrete is best characterized by its compressive strength and relatively low in cost as well as the availability of ingredients that makes it the most favorable component of construction compared to other materials like steel. However, this...
Space-earth coupling with relation to earth’s thermal capacity: A case study for Nsukka Region, Nigeria
January 2022
The radiation coming from the sun to the earth is the only form of incoming radiant energy that determines the heat balance and thermal regime of the earth. Variation of solar radiation is the single most important factor affecting the earth’s surface temperature. This study seeks to investigate the relationship between ambient temperature and soil temperature with a view to determine the existence of space-earth...
Mantle electrical conductivity determination employing the ionospheric solar quiet day (Sq) currents in the Southern African regions
January 2022
Solar quiet (Sq) daily currents variation obtained in the Hermanus (34.34oS, 19.22oE), Tsumeb (19.24oS, 17.72oE), Hartebeesthoek (25.68oS, 28.09oE) and Maputo (25.97oS, 32.57oE), were employed in determining the mantle electrical conductivity depth profile of the Southern African region. The external and internal contributions in the solar quiet field were separated using the spherical harmonic analysis (SHA), after...
Theoretical and experimental studies of effective carriers lifetime: Magnetic effects
December 2021
In this manuscript, we present a study on the effects of magnetic field on charge carrier effective lifetime within the base of a polycrystalline PV solar cell p-n junction. This study is elaborated in two forms as a theoretical study and an experimental study. Indeed, under various magnetic field values, PV solar cell is illuminated by using the light from stroboscopic. From a theoretical approach mainly use the open...
Plastics: The good, the bad and the ugly
December 2021
Plastics’ demand and consumption is on the increase since 1950s due to their unique properties. Their high use coupled with challenges in end-of-use handling and their inherent resistance to degradation has led to their accumulation in the environment, which is a matter of grave concern. This review presents a general overview of the state of knowledge of the diverse faces of plastics with special reference to...
Solar activities and geomagnetism: Long-term statistical study of magnetics clouds activity day’s occurrence as a function of the phases of solar cycles 11 to 24
December 2021
This article examines magnetics clouds activity day’s occurrence as a function of the different phases of the solar cycle and the duration of their geoeffectiveness. The study period extends from cycle 11 to cycle 24. Magnetic clouds activity day’s occurrence were identified using pixel diagram from the years 1867 to 2019, that is to say, fourteen (14) solar cycles. The results show that in the study period:...
Monitoring the loss of mass or the volume recessed into a waveguide by resonant signal principle: Nano-inscribed slots in DUV210 micro-resonators
November 2021
The goal of this paper is to study the impact of a differential mass loss or a lack of material (void) directly located into the core structure of matter together with the possibility of measuring its effect by a resonant signal surface at optical frequencies. To this end, the focus has been on the evolution of effective indices or eigenvalues of micro-resonators as relevant models. Specific lack of mass was measured by...
High pressure phase stability, elastic anisotropy and electronic properties of BC2N
November 2021
Crystal lattice structure searching by Particle Swarm Optimization (PSO) and first-principles structural optimization have been used to explore polymorphs of BC2N, possessing sp3 hybridization, under a varying applied hydrostatic pressure. Two low Gibbs free energy structures were identified: one with a primitive orthorhombic structure and Space Group, Pmm2, and the other with a primitive tetragonal structure and Space...
Performance analysis of the 23 MWp grid connected photovoltaic plant in Diass Senegal
October 2021
This paper presents the performance analysis of a 23 MWp photovoltaic solar power plant installed in Diass, Senegal. The solar photovoltaic power plant is composed of 85608 polycrystalline PV modules and 8 transformer stations (TS). Each TS consists of 4 inverters, several DC BOX and 2 transformers. The environmental and performance data of the plant used in this work were recorded throughout the year 2020. The...
Design, green synthesis and reactions of 2,3-dioxo-1,2,3,4-tetrahydroquinoxaline-6 sulfonohydrazide derivatives
October 2021
2,3-Dioxo-1,2,3,4-tetrahydroquinoxaline-6-sulfonohydrazide and its derivatives were synthesized and characterize by IR, 1H-NMR, 13C-NMR and mass spectrometry analytical methods. The 2,3-dioxo-1,2,3,4-tetrahydroquinoxaline-6-sulfonyl hydrazide (compound 1), was synthesized from the reaction of o-phenylenediamine with oxalic acid to obtain quinoxaline-2,3-dione, which was subjected to chlorosulfonation with chlorosulfonic...
Total electron content (TEC) seasonal variability under fluctuating activity, from 2000 to 2002, at Niamey station
October 2021
This paper presents the Total Electron Content variability, during the solar cycle 23 maximum under geomagnetic fluctuating activity conditions from 2000 to 2002 at Niamey station (lat. :13°28’N ; long : 2°10’E) in Niger. A comparative study of TEC profiles variation under quiet and fluctuating geomagnetic activity conditions allowed us to analyze the effects of fluctuations in solar wind on...
Physical-chemical characterization of kanyu almond oil (Sclerocarya birrea) for use as biofuel
September 2021
Plant oil extracted from Kanyu almonds offers the potential to be an alternative to fossil fuel resources. This study aims to characterize the physico-chemical properties of kanyu almond oil, as safe indicators of the use of this biofuel for energy generators. Samples of the oils examined were density, kinematic viscosity, acid value, and oxidation stability. The experimental results showed that the oils had different...
Thick lenses systems
July 2021
The matrix optics formalism is applied to show that a simple Gaussian equation is enough to relate object and image distances in an optical system consisting of an arbitrary number of thick lenses in cascade immersed in air. First, the case of a single thick lens was studied. Applying sequentially the optical matrixes corresponding to refraction and displacement of the optical ray, and imposing certain conditions on the...
Adsorption and thermodynamic studies of the corrosion inhibition effect of Rosmarinus officinalis L. leaves on aluminium alloy in 0.25 M HCl and effect of an external magnetic field
May 2021
The corrosion inhibition of Aluminium alloy AA8011 in 0.25 M hydrochloric acid solution by Rosmarinus officinalis L. (rosemary) leaves extract was studied using the gravimetric technique at 303, 313, 323 and 333K, and in the presence of an external magnetic field. The study reveals that the methanolic extract of rosemary leaves inhibits corrosion of Al in 0.25 M HCl. The inhibition efficiency was found to increase with...
Evaluation of PV performance prediction model in tropical environment in Senegal
April 2021
Many authors in the literature have worked on models for producing PV module performance, but the question of a climate-specific model is problematic. Some studies have shown more appropriate models for any PV module technology, while others have highlighted models that are more appropriate for a given climate. The aim of this work is to evaluate our model which is based on the I-V characteristic and their accuracy was...
Analysis of wind distribution and potential wind energy in Senegal with a focus on Basse Casamance
April 2021
This work uses the Weibull distribution for assessing the wind potential in Senegal; a country located in West Africa. In this study, data from the ERA5 reanalysis and the Ziguinchor station were used to characterize the spatio-temporal variability of wind and its available power density at 10 m and 100 m of altitude. The results showed that the wind potential was stronger on the coast and the north-western part of the...
Evaluation of the anti-microbial efficiency of scrap metal-based coagulant and local salt modified-biomaterials for point-of-use water treatment
March 2021
The anti-microbial efficiency of a composite material formulated from a scrap metal-based (iron (III) sulphate) coagulant and indigenous salt (NaCl) activated biomaterials (coconut shell carbon and counter wood) were evaluated by using the composite materials as coagulant and disinfectant adsorbent by treating borehole water and river samples at point-of-use. The results of the microbial analysis of the untreated and...
Test of velocity-displacement estimation using variometric method under the condition of ionospheric scintillation during equinoctial months of solar maximum period 2012
February 2021
The Global Navigation Satellite System (GNSS) technologies have made significant contribution to seismology studies. Some processing strategies are well known, like real time PPP and DGPS techniques. These two methods have been widely used for GNSS based seismic activities monitoring. The first method requires accurate models of GNSS measurement errors to achieve accuracy in centimeter (cm) and need convergence time in...
Stability and elastic anisotropy of diamond related C8-yBy materials
February 2021
A number of potentially super-hard materials were examined using ab-initio methods. Low Gibbs free energy polymorphs of diamond-like materials for y = 0 to 7 in the stoichiometric type C8-y By, were identified at absolute zero of temperature. These were proposed as possible super-hard materials with useful applications. The materials with y = 0 to 3, that is, diamond (C), cubic C7B (c-C7B), rhombohedral C3B (r-C3B) and...
Evaluation of simulated rain-based attenuation techniques at k-v frequency bands for satellite services under different modulation techniques over Southwestern Nigeria
January 2021
Rain-based attenuation (RBA) is a major deteriorating factor affecting radio wave signals operating at microwave and millimetre wave bands for a typical Earth-Space Communication Link (ESCL). Although the international telecommunication union (ITU) recommended a standard model for predicting RBA along the terrestrial and ESCL, the technique underperforms in tropical environments. However, the model can be supported by...
Analysis and feasibility of 50 kWp self-consumption solar photovoltaic system for four Senegalese typical climatic zones using PVsyst software
December 2020
This study investigates analysis and feasibility of 50 kWp self-consumption photovoltaic system used for supplying the electrical load of military bases in Senegal. It refers to a simulation of performance photovoltaic system in four Senegalese typical climatic zones. In constructing the 50 kWp self-consumption photovoltaic simulation, the number of modules is 144, the power of each module is 280 Wp, 18 modules are in...
Coherent perfect absorption in plasmonic planar metasurface
December 2020
The coherent perfect absorption (CPA) for a planar resonator of silver has been elaborated here in numerical and analytical approaches. It is investigated numerically in different geometrical shapes and spectral regimes. The CPA mode is observed to be spectrally sensitive to the geometry of the resonator. The scattering matrix method is employed in theoretical analysis. The CPA conditions and output irradiance...
River water lever sensor as river flood warning system
October 2020
Senate Report recorded last 2013 show that tropical storms and floods are the principal disasters with 102 and 72 occurrences, respectively. Distinctly, flood is still one of the biggest problems of the country. Statistics shows that 31.9% of the natural disasters, which occur in the Philippines in the years 1990-2014, are attributed to flood related episodes with a mortality rate of 5.9%. The researchers seek to...
Effects of elevated humidity on stratospheric ozone content in the tropics
October 2020
This study examines the effects of elevated humidity on stratospheric ozone content in the tropics, a case study of Nigeria. The specific stations in Nigeria studied with their co-ordinate include Makurdi (7.7°N 8.5°E), Maiduguri (11.9°N 13.2°E), Kano (12.0°N 8.5°E), Port-Harcourt (4.9°N 7.0°E) and Lagos (6.5°N 3.4°E). Using monthly mean stratospheric ozone data from Earth Probe...
Preparation of MWCNT/Ba0.2Sr0.2La0.6MnO3/PANI nanocomposites and investigation of its electromagnetic properties in KU-band
October 2020
The aim of this study was enhanced the absorption of electromagnetic waves by nanocomposite containing polyaniline (PANI), functionalized multi wall carbon nanotubes (MWCNTs) in the presence of magnetic Ba0.2Sr0.2La0.6MnO3 nanoparticles (NPs). At First MWCNTs was functionalized by 3:1 ratio of sulfuric and nitric acid, then functionalized MWCNTs was coated by NPs with the traditional sol-gel method. In the final step,...
Optical and scanning kelvin probe microscopic characterization of sol-gel synthesized aluminum doped zinc cobalt ferrite nanoparticles
October 2020
In this work, Zn1-xCoFe2AlxO4 (x=0, 0.2, 0.4, 0.6, 0.8 and 1.0) ferrites were synthesized using the sol-gel method. XRD analysis was done and confirmed the formation of spinel structure, where the particle size and lattice parameter decrease with increase of aluminum concentration. This may be attributed to a shift of the bigger Al3+ ions, from the tetrahedral to the octahedral sites, interchanging with smaller Zn2+...
Fof2 prediction with IRI-2016 at Dakar Station during quiet activity over solar cycles 21 and 22
October 2020
This study deals with comparison between Dakar station ionospheric’s F2 layer critical frequency (foF2) data and the two subroutines (CCIR and URSI) of IRI-2016 model predictions. Comparisons are made for very quiet geomagnetic activity during the four phases of the solar cycles 21 and 22 (minimum, increasing, maximum and decreasing). Model's predictions are suitable with observed data by day than by night....
Modification of plastic tank for bio-digestion of food wastes for biogas generation for cooking foods
October 2020
The anaerobic states of the modified bio-digester and potentials of the generated biogas in cooking foods were evaluated. The study adopted experimental design. Data generated were analyzed using one - way analysis of variance and independent t-test. Carbon, free fatty acid, chemical and biochemical oxygen demand decreased significantly (p<0.05) while moisture and protein contents of the wastes increased...
Application of integrated geophysical methods in environmental studies: A case study of oil spillage in Thange Area Makueni County, Kenya
August 2020
This research was conducted with the aim of mapping the extent of soil and ground water hydrocarbon contamination from an oil pipeline leak point within the area. An integrated geophysical survey approach involving horizontal electrical profiling (HEP), vertical electrical sounding (VES) and Gravity Survey was applied. Resistivity and gravity lows were identified as aquifer zones confined within basalts and potential...
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