May 2019
Multivariate statistical assessment and spatial distribution of groundwater contamination in Neke and its environs, South-Eastern Nigeria
Groundwater quality in Neke area of southeastern Nigeria was investigated applying multivariate statistical analyses using Statgraphics centurion XVII, ArcGIS 10.2.2 and Surfer 10 software on hydrochemical and bacteriological data from 25 groundwater samples over land cover of about 1283 km2 , in order to unravel the factors influencing ground water quality. From the correlation analysis, Ca2+, Mg2+, K+, and SO42-...
May 2019
Magneto-Stark effect on exciton in parabolic bandGaAs/〖Ga〗_(0.7) 〖Al〗_(0.3) As quantum well heterostructure
The effect of applied crossed electric and magnetic fields on the heterostructure semiconductor is used in the scientific investigation on electronic and optical exciton properties. The aim of this work is to study the magneto-Stark effect for confined excitons in single GaAs-〖Ga〗_(0.7) 〖Al〗_(0.3) As QWs. The magnetic field B is taken as perpendicular to the z-growth direction of the heterostructure, whereas the applied...
April 2019
Estimation of sedimentary thickness using spectral analysis of aeromagnetic data over Otukpo and Ejekwe areas of the lower Benue Trough, Nigeria
The aeromagnetic data of Otukpo (sheet 270) and Ejekwe (sheet 289) areas of the lower Benue Trough of Nigeria were interpreted quantitatively. The quantitative interpretation employed spectral analysis technique with the aim of locating specific basement depths to buried magnetic source rocks in the study area. First order polynomial fitting was adopted for regional-residual separation of the total magnetic intensity...
April 2019
A study on the effects of solar wind and interplanetary magnetic field on geomagnetic H-component during geomagnetic storms
During geomagnetic storms, the geomagnetic H component is depressed which is preceded by a sudden storm commencement (SSC) or not and this is categorized as sudden or gradual storms. Using the method of cross correlation analysis, we have studied the associations of geomagnetic H components at four low latitude stations at longitudinal separations of 145° - 215° with solar wind density and interplanetary...
March 2019
Magnetic source basement depth determination of Ikogosi Warm Water Spring South Western Nigeria and the environ using aeromagnetic data
Structural features of Ikogosi Warm Spring and its environs have been delineated using qualitative and quantitative interpretation methods. Euler-Deconvolution and local wave number methods were adopted for quantitative and qualitative interpretation of aeromagnetic data sheet 243 by Geological Survey Agency of Nigeria (GSN) in 2008, respectively. Euler solution revealed depth range of -2.98 to -290 m to the magnetic...
March 2019
Structural, magnetic and transport properties of samarium (Sm) doped Cu-Zn ferrites
The present work is focused on investigating the effect of rare earth ion on structural, magnetic and transport properties of (Cu0.5Zn0.5Fe2-x)SmxO4[x = 0.00, 0.05 and 0.10] ferrites which were prepared by solid state reaction technique at 1100°C for 3 h. The X-ray diffraction analysis revealed that rare earth free sample shows formulation of single phase cubic spinel structure with no extra peak whereas Sm...
January 2019
Thermospheric neutral winds over Abuja, Nigeria
We present nighttime variation of thermospheric winds estimated from the Fabry-Perot interferometer (FPI) which was recently deployed at Abuja in Nigeria. These results apply to the thermosphere region around 250 km and were obtained during the period of weak solar activity with solar flux values generally below 70 s.f.u. The results presented cover three months, from October 2017 to December 2017. The high geomagnetic...
January 2019
Spectral analysis and source parameter imaging of aeromagnetic data of Lafia and Akiri Areas, Middle Benue Trough, Nigeria
This study aimed to estimate the depth of magnetic source bodies in Lafia and Akiri areas which fall within the middle Benue trough, Nigeria. Aeromagnetic data were used and spectral analysis and source parameter imaging were used for the quantitative interpretation of the data. The total magnetic intensity (TMI) contour map obtained from gridding of the data ranging from -39.5 to 100.0 nT was separated into regional...
December 2018
Assessment of outdoor radiation levels and radiological health hazards in Emene Industrial Layout of Enugu State, Nigeria
A study to assess the outdoor Background Ionizing Radiation (BIR) levels in Emene Industrial Layout of Enugu State, Nigeria has been conducted. An in-situ measurement of BIR exposure rate in mRh-1 for 30 locations was done using a well calibrated portable GQ GMC-320 PLUS nuclear radiation detector at an elevation of 1.0 m above ground level with a geographical positioning system (GPS) for geographical location. The...
December 2018
Magnetosphere convection electric field (MCEF) time variation from 1964 to 2009: Investigation on the signatures of the geoeffectiveness coronal mass ejections
The signatures of the geoeffectiveness solar disturbed events on the Magnetosphere Convection Electric Field (MCEF) universal time variation from 1964 to 2009 are investigated. Here, attention is focused our on the periods concerned by the whole shock activity and by the different types of the geoeffectiveness Coronal Mass Ejections (CMEs) which are one-day-shock, two-days-shock and three-days-shock. The investigation...
December 2018
Noise exposure levels and health implications on daily road side petty traders at some major roundabouts in Ibadan, Nigeria
The level of noise exposure to daily road side traders at five major roundabouts in Ibadan metropolis was assessed. Noise measurements were made using a precision multi-function sound level meter. Measurements were made at three different periods of the day; morning (7:30 to 11:30 a.m.), afternoon (12:00 to 3:00 p.m.) and evening (4:00 to 5.00 p.m.) for a consecutive period of ten days. The highest mean maximum noise...
November 2018
Mathematical modeling and numerical simulation for the formation process of nanofilms
This study applied a generalized model to describe and optimize the formation process of nanofilms from their polymeric solutions. Through this model, one can optimize the concentration of the solvent in the polymeric solution, the appropriate geometric dimensions as well as the nanofilm formation speed. A comparison of this model with experimental data has revealed some similarities and differences in the...
October 2018
Deriving an expression for electron-reflection-coefficient at metal-semiconductor-interface of dye-sensitized solar cells
This work aims to derive an expression to describe the reflection coefficient of an escape electron from metal-semiconductor interface of DSSC. The derivation was obtained by analytically solving electron diffusion equation with assumptions of steady state DSSC and negligible current flow at the outer most part of the film. The derived corrected Richardson-Dushman equation including a reflection of electron wave...
October 2018
Quantification and correction of the Thomsen’s Delta Anisotropy for improved quantitative seismic interpretation in “AMFO” Field, Western Niger Delta
The Niger Delta is a sedimentary deposit with continuing sediment deposition to date. In a stratified earth, seismic waves tend to propagate faster along layers than across layer boundaries. Shales, due to the clay minerals they contain, exhibit similar behavior. As a result, velocities derived from surface seismic are often faster than well-derived velocities, causing depths of structures from surface seismic...
August 2018
Radionuclide concentration: The coal ash effect
Radionuclide concentrations in coal ash, soil mixed with coal ash and soil were determined using the gamma spectroscopic method. The average activity concentrations of 226Ra, 232Th, and 40K in coal ash samples were found as 35.0, 5.8, and 109.4 Bq/kg, respectively. The average activity concentrations of 226Ra, 232Th and 40K in soil mixed with coal ash samples varied from 21.2 to 30.8, 48.6 to 82.7, and 162.5 to 180.1...
July 2018
Mineralogical and geochemical properties of clay deposits in parts of Southeastern Nigeria
The rocks underlying many parts of Southeastern Nigeria had undergone extensive alterations to form considerable clay deposits. The mineralogical compositions of some of these clay deposits were evaluated with the X-Ray Diffraction (XRD) method to ascertain the suitability of the deposits as raw materials. Results of the analyses indicated that kaolinite (Al2Si2O5 (OH)4) is the dominant clay mineral. Traces of bentonite...
July 2018
Theoretical models for prediction of methane production from anaerobic digestion: A critical review
This work presents a critical analysis for three models group of methanogen potential prediction. The first group allows determination of the methane productivity of substrates, through three models (BMPthCOD, BMPthAtC and BMPthOFC). The BMPthCOD is suitable for a first approximation calculation. BMPthAtC and BMPthOFC are more accurate; however, require a complex characterization of substrates. The second models group...
June 2018
Energy and exergy analysis of a solar photovoltaic module performance under the Sahelian Environment
This work focuses on the performance study of a photovoltaic solar module based on energy and exergy analysis. The experimental data were obtained by precise measurements during a clear sky day March 20, 2018 and a cloudy day March 27, 2018 in the Laboratory of Chemistry and Materials Physics (LCPM) at the Assane Seck University of Ziguinchor, Senegal (12° 34 N, 16° 16 E). Exergy, energy and power conversion...
June 2018
Gross alpha and beta activity concentrations in soil and some selected Nigerian food crops
Gross alpha and beta activity concentrations in soil, cassava and fluted pumpkin (leaf and stem) were investigated using a gas flow proportional counter. The gross alpha activity concentrations for the fluted pumpkin were between 3.55 and 13.95 Bq/Kg and 3.53 and 3.61 Bq/Kg for the leaves and stems, respectively. The gross alpha activity concentrations for cassava and soil samples ranged from 0.07 to 0.60 Bq/Kg and 0.35...
June 2018
Effect of annealing temperature on the optical properties of Sb-ZnO thin films prepared using co-sputtering technique
Transparent conducting oxide thin films of Sb-ZnO were prepared on optically flat quartz by radio-frequency (RF) sputtering method. The scan electron microscope was used to characterize the topological morphology of the surface of the as-prepared and annealed films at (300, 400, 470, and 525°C) for 4 h in air. The optical properties of the films were deliberated using their reflectance and transmittance spectra at...
May 2018
Comparative analysis of physical and chemical characteristics of selected clays deposits found in Kebbi State, Nigeria
The intent of this paper was to explore the physical and chemical characteristics of clays in Kebbi State, Nigeria, and the clays were compared with standard clay which is considered with highest quality standard in casting. Clay’s deposits from Dukku River along River Rima, Jega River which is the tail end of River Niger and Yauri were investigated for their potentials as raw materials used for casting and...
May 2018
Optical and structural performance of polymer/fullerene thin film based on Poly (3-hexylthiophene)/1-(3-methoxycarbonyl)propyl-1-phenyl[6,6]C61 [(P3HT)/PCBM] after post-annealing
The polymer solar cell is a promising candidate for the next-generation solar cells because of its light weight, flexibility and easy fabrication. Poly (3-hexylthiophene) (P3HT) and 1-(3-methoxycarbonyl) propyl-1-phenyl[6,6]C61(PCBM) are, to date, the most-studied active materials around the world for bulk-heterojunction structure. Recent power-conversion efficiencies are reported up to approximately 13%. This research...
May 2018
Seven-dimensional space-time and its objects: Arbitrary spin state, electromagnetic fields, mirror symmetry and superconductivity
To form the basis spin states of a field, vector states of the multicomponent wave function to the four coordinates of Minkowski space that determine the position of the local observer have been added by angular extra dimensions that determine the orientation of the local observer. The generators of the Poincare group in the angular representation have been obtained. The Dirac equation (generalized for any spin)...
May 2018
Correlation of geotechnical parameters with geological formations in a basement complex and its implications on civil structure foundation
Geotechnical tests were carried out on twenty subsoil samples obtained from ten locations at the depth of 1 and 2 m within Federal University of Technology, Akure, Nigeria. The area is typical of basement complex. The test include; Natural Moisture Content, Grain Size Analyses, Specific Gravity, Atterberg Limits, Compaction, California Bearing Ratio (CBR), and Unconfined Compression Tests. The ten locations where the...
April 2018
Feasibility analysis of hybrid electricity generation system by HOMER for Mauritanian northern coast
The reported work was motivated by the energy needs in the Mauritania region and the utility of the search features of a software system, named HOMER (Hybrid Optimization of Multiple Energy Resources), for feasibility analysis of a hybrid power generation system (HS) for the Mauritanian northern coast. This study analyzed a sample of the available wind resources to meet the energy needs of these localities, using the...
April 2018
Investigating influence of the phases of solar activity cycle 23 on coronal mass ejections transit time
It has been established that Coronal Mass Ejections (CMEs) follow the phase of solar activity cycle. CMEs are known to be the major cause of geomagnetic storms which have devastating effects on earth atmosphere. Predicting their arrival times has been a major issue in space weather forecast. Influence of the phases solar activity cycle 23 on CMEs transit time were investigated using fast CMEs data with initial speed...
April 2018
A compact and sensitive avalanche photodiode-based gamma detection and spectroscopy system
This research presents the design of a simple and compact yet sensitive gamma detection system which finds optimal utility in student research and demonstration purposes. The design is based on an Avalanche Photodiode (APD), a compact solid-state device. It was argued that, by the virtue of its concise size, simplicity and lower cost, an APD based gamma detection system is a better alternative in these applications as...
March 2018
A comparative study of Nigerian GNSS Reference Network’s – Global Positioning System (NIGNET’s-GPS) vertical Total Electron Content (vTEC) measurements with the International Reference Ionosphere - Total Electron Content (IRI-TEC) predictions over Calabar, Nigeria
A study of the vertical Total Electron Content (vTEC) values as measured by the Nigerian GNSS Reference Network’s (NIGNET’s) GPS receiver in Calabar with geographic coordinates: 4.95°N, 8.32°E and geomagnetic coordinates: 6.46°N, 81.59°E has been carried out for some selected days in the year 2013. The results obtained are compared with the corresponding predictions of the three topside...
March 2018
Comparative study of commercial gas with biogas produced from co-digestion of corn cob, rice chaff, goat and dog dungs
Investigations were conducted to compare gas produced from co-digestion of corncob, rice chaff, goat dung and dog dung with commercial gas. The study was carried out anaerobically at a temperature of 29.5 to 33°C (mesophilic condition) in a mini laboratory digester (bioreactor) fabricated using guage 16 metal sheets with 80-L capacity for a 90-day retention time. The shredded corn cob and rice chaff were mixed with...
March 2018
On the effect of convective heat and mass transfer on unsteady mixed convection MHD flow through vertical porous medium
In this paper, unsteady two-dimensional convective heat and mass transfer flow of a viscous, incompressible, electrically conducting optically thin fluid which is bounded by a vertical infinite plane surface was considered. A uniform applied homogeneous magnetic field is considered in the transverse direction with first order chemical reaction. An analytical solution for two-dimensional oscillatory flow on...
March 2018
Simulation of the impact of climate change on peanut yield in Senegal
This paper treats the impacts of climate change on peanut yield in Ziguinchor (Southwest of Senegal) during the near future (2021 to 2050) and the far future (2071 to 2100). The Decision Support System for Agrotechnology Transfer (DSSAT) crop model was run using daily weather data (maximum and minimum surface temperature, rainfall and solar radiation) of four (4) regional climate models (RCMs) of the Coordinated...
February 2018
Interpretation of aeromagnetic data over some parts of Mambilla Plateau, Taraba State
The data covering Mayo Daga and Gashaka areas of Taraba State has been interpreted by applying source parameter imaging (SPI) and forward and inverse modeling methods. From the quantitative method of interpretation, it was found out that the magnetic intensity within the study area ranges from -129.9 to 186.6 nT in which the area is noticeably marked by both low and high magnetic signatures which may be as a result of...
February 2018
Improvement of the homotopy perturbation method to nonlinear problems
This paper proposes an effective improvement of the homotopy perturbation method (HPM) by using Jacobi and He's polynomials to solve some nonlinear ordinary differential equations. With this method, the source terms of ordinary differential equations can be expanded in series of shifted Jacobi polynomials. Numerical results are given in this paper to illustrate the reliability of this method with nonlinear ordinary...
February 2018
Investigation of gravity anomalies in parts of Niger Delta Region in Nigeria using aerogravity data
Gravity anomalies in parts of the Niger Delta region, Nigeria, were investigated through the interpretation of aerogarvity data with the objectives to determine the thickness of the sedimentary basin, establish the basement topography, density contrasts and the geological models which will give information about variation of geological structures. Four sheets of digital airborne gravity data were used for the...
February 2018
Green synthesis of silver monometallic and copper-silver bimetallic nanoparticles using Kigelia africana fruit extract and evaluation of their antimicrobial activities
Aqueous extract of Kigelia africana fruits have been utilized in the syntheses of silver nanoparticles (AgNPs) and copper-silver bimetallic nanoparticles (Ag-CuNPs). The synthesized nanoparticles have been characterized using UV-vis, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy/energy dispersive X-ray analysis (SEM/EDX), x-ray diffration (XRD) and transmission electron microscopy (TEM)....
January 2018
High-latitude thermospheric zonal winds during low solar activity period
Changes resulting from the cyclical nature of the sun’s energy output result to variations in thermosphere-ionosphere system parameters. The prolonged low solar activity period of solar cycle 23 provides an opportunity to study the thermosphere-ionosphere system parameters when the sun was at its ground state. The CHAMP satellite has provided wind data that can be used for investigation of neutral thermospheric...
January 2018
Study of the performance of a system for dry cleaning dust deposited on the surface of solar photovoltaic panels
This study was carried out at the International Center for Training and Research in Solar Energy (CIFRES) and its main purpose was to study the performance of a solar module cleaning system. To handle this work, a measuring platform consisting of two polycrystalline (pc-Si) PV modules was designed. The modules were connected to a waterless cleaning system on the surface of the solar panels. The platform also contained a...
January 2018
A comparative study of maximum power point tracker approaches based on artificial neural network and fuzzy controllers
The performances of a photovoltaic (PV) module connected to a load through a conversion stage (chopper, inverter) are linked to the average electricity output including the delivered power. Nevertheless, the efficiency depends on atmospheric parameters as temperature, irradiance, and wind speed. To make electrical power available, Maximum Power Point Trackers (MPPT) algorithms are developed to keep up the PV module at...
December 2017
Spectroscopy and chemical analysis of natural dye from Sorghum bicolour
Many plants produce very attractive flowers, leaves and fruits. Colour pigments that are derived from nature are believed to be environmentally friendly because of their non-toxic, non-carcinogenic and biodegradable nature. In this project, colour pigment from ethanol extract of Sorghum bicolour was investigated using three different spectroscopic techniques (UV-Vis, FT-IR and GC/MS). The effects of dyeing parameters;...
December 2017
Microstructure and mechanical properties correlation for the steel: A comparative methodology of educational research for physics and mechanical engineering trainings
An academic methodology based for experimental evaluation of materials treatment is presented. The study is centered in an educational research emphasis about microstructure evaluation and heat treatments in steels samples machined according to ASTM E8 specifications. The uses of metallographic techniques and hardness/tensile tests for analyzing experimental variations due to structural changes are included. Different...
December 2017
Intersection of lineaments for groundwater prospect analysis using satellite remotely sensed and aeromagnetic dataset around Ibodi, Southwestern Nigeria
This research investigates groundwater potential of Ibodi and its environs using satellite imagery remotely sensed and aeromagnetic dataset. This hydrogeological investigation involved the extraction of lineaments from Landsat Thematic Mapper (TM) satellite imagery and aeromagnetic lineament of the area. The processed image revealed lineaments trending in approximately NE-SW direction; also, Landsat and aeromagnetic...
November 2017
Variability of quiet-time diurnal amplitude and phase of cosmic ray count rates in the mid- and high latitudes
Studies have been done on the variability of cosmic rays flux during solar quiet days at mid and high latitudes. By using the 5 quietest days for each month, the monthly mean diurnal variation of cosmic ray anisotropy have been derived for the period 1981 to 2007, which covers part of cycles 21, 22 and 23. These quiet days are days during which the sun is relatively magnetically quiet, leading to less anisotropic...
November 2017
Investigation on equinoctial asymmetry observed in Niamey Station Center for Orbit Determination in Europe Total Electron Content (CODG TEC) variation during ~ solar cycle 23
This is an investigation of equinoctial asymmetry in Total electron content (TEC) variability at Niamey (Latitude: 13° 30' 49.18" N, Longitude: 2° 06' 35.28" E) using the Global Ionospheric Maps model constructed by the Center for Orbit Determination in Europe (CODG model) during solar cycle 23, that is, from year 1999 to year 2009. Niamey Center for Orbit Determination in Europe...
November 2017
Estimation of sedimentary thickness using spectral analysis of aeromagnetic data over Abakaliki and Ugep areas of the Lower Benue Trough, Nigeria
Aeromagnetic data over Abakaliki and Ugep areas of the lower Benue Trough were interpreted to determine the depth to magnetic source rocks of the area. The study area covered latitudes 5° 30' and 6° 30'N and longitudes 8° 00' and 8° 30'E with an estimated total area of about 6000 km2. Quantitative interpretation was carried out using spectral analysis method to compute for depth to...
November 2017
Solar wind plasma associated with Dst < -50 nT during solar cycle 24
This study analyzed the correlative study between the peak intensity of the geomagnetic storm, interplanetary magnetic field (IMF) and the peak value of various plasma parameters during the solar cycle 24. This study has been performed using hourly values of the geomagnetic storm time (Dst) < -50 nT for the period 2008 to 2016. 173 events of disturbance storm time with solar wind velocity ≥ 350 km/s were selected...
November 2017
Evaluation of the impact of partial shading and its transmittance on the performance of crystalline silicon photovoltaic modules
This paper presents on the one hand, an evaluation of the impact of partial shading on the performance parameters of two photovoltaic modules respectively in poly and mono. The current-voltage characteristic (I-V), the short-circuit current (Icc), the open-circuit voltage (Vco) and the maximum power (Pmax) were studied. In this work, the measurements were carried out under the standard conditions (STC) in order to make...
October 2017
Models for calculating monthly average solar radiation from air temperature in Swaziland
Solar radiation is an important energy source for mankind. Accurate data of solar radiation levels for a particular location is vital for optimum operation of solar energy transducers such as photovoltaic cells and solar thermal collectors. In this work, it is shown a linear relationship exist between monthly average temperatures and solar radiation in Swaziland. The correlation has been utilized to develop two...
October 2017
A study of semi-annual variation of residual geomagnetic field and its association with solar and geomagnetic activity
The semi-annual variation of the residual H and Z components of geomagnetic field was studied by analyzing magnetograms with sixty-one years data. Mean monthly residual H- and Z-component field (Hdiff and Zdiff) variations were computed using appropriate technique. Semi-annual variation exhibited Hdiff peaks in the equinoxes, which for low latitudes, was higher during March/April than in September/October. In the mid...
October 2017
Radioactivity in building materials in Saudi Arabia: An overview of experimental method and Monte Carlo N-Particle (MCNP) calculation
The aims of this work were clearly to assess the norms of radiation protection for building residents against natural radioactivity. This was done through measurement of natural radioactivity in building materials using gamma ray spectrometer. The annual effective dose (HR) linked to natural radioactivity was computed to estimate the radiation hazard in building materials. Obtained concentrations of these natural...
October 2017
Spectral depth analysis for determining the depth to basement of magnetic source rocks over Nkalagu and Igumale areas of the Lower Benue Trough, Nigeria
Structural interpretation of aeromagnetic data over Nkalagu-Igumale area of the Lower Benue Trough of Nigeria was carried out to determine the depth to magnetic basement and delineate the basement morphology and the structural features associated with the basin and their trends. The aeromagnetic data were subjected to series of computer based image and data enhancement techniques before spectral analysis. Results of the...
Page 1 of 50, showing 50 records out of 2486 total, starting on record 1, ending on 50
