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...
October 2017
Analysis of organochlorine and organophosphorus pesticide residues in blood samples of sheep and rabbits from villages of Jimeta-Yola, Adamawa State, Nigeria
Blood samples of sheep and rabbits from five different villages of Jimeta-Yola, Adamawa State, Nigeria were collected for determination of organochlorine and organophosphorus pesticide residues. Preparation of blood samples was carried out using standard procedure of QuEChERS method of extraction. The concentrations of all the pesticides in blood samples of sheep and rabbits were determined using Gas...
October 2017
Assessment of natural radionuclide levels in some Nigerian made poultry feedstuff
This study investigated the radionuclide contents of naturally occurring radionuclides. Ten samples of some Nigerian made poultry feedstuff and supplements were collected and analysed using NaI(Tl) gamma(𝛾)-ray spectroscopy for an accumulated time of about 29000 s. The results revealed that activity concentration of primordial radionuclides 40K, 226Ra, and 232Th for the samples ranged from 43.6 to 196.8 Bq/kg, 5.0 to...
September 2017
Optimization of electrical production of a hybrid system (solar, diesel and storage) pilot using HOMER in Biret, Southern Coast of Mauritania
The purpose of this work is to study the optimization of an hybrid system of electricity production (solar-diesel with storage) of Biret (Mauritania) using the Hybrid Optimization Model for Electric Renewables (HOMER) software. Indeed, it shows that the context and behavior of the chosen system is optimal. HOMER is used to present simulations in the most economical way. It is important to note that the application of...
September 2017
Studies on equalities and inequalities of heat, work and ratio of work to temperature
This research investigates relationships between resistances with heat and work. It is completely proven that the ratio of work to temperature for the realistic process is no less than that for the reversible process. The equalities and inequalities on the heat, work and ratio of work to temperature could be applied to the gravitational field and chemical reactions. The relationships between path functions and state...
August 2017
Problems with p6Li plasma in a fusion reactor
Problems of using proton-Lithium-6 (p6Li) fuel are energy losses that occur in a fusion reactor. Investigating the energy balance equation in this fuel is significant. The p6Li reaction is termed aneutronic, as it produces relatively few neutrons and requires none for breeding. The energy from the charged reaction products can be directly converted to electrical power at a much higher efficiency than Deuterium-tritium...
August 2017
Application of Ojih-Okeke modified empirical coronal mass ejection arrival (ECA) model in predicting the arrival time of coronal mass ejections (CMEs)
Predicting the arrival time of Coronal Mass Ejections (CMEs) with a lower value of average error of the difference between the predicted and the observed transit time is very crucial in space weather forecast. A modified Empirical Coronal Mass Ejection Arrival (ECA) model was proposed, namely, Ojih-Okeke modified ECA model to predict the transit time of twenty eight fast CMEs from the sun to the earth. This is the first...
August 2017
Simulation of precipitation variations in Iran using Kriging interpolation methods
This study estimated spatial variability of precipitation in the monthly and annual scales in Iran for the period of 1975 to 2014 in 140 stations using kriging interpolation methods. In precipitation variability analysis three procedures were used: Mann-Kendall test, Sen's slope estimator and spatial trend patterns. Results show that there are both increasing and decreasing trends in monthly precipitation in Iran....
August 2017
Influence of solar and geomagnetic activity on climate change in Nigeria
This study investigates the possible effects of solar and geomagnetic activity on climatic parameters in Nigeria. Data of sunspot number and geomagnetic aa index from 1950 – 2012 and 1950 – 2010 were used as solar indices respectively. Monthly mean daily rainfall, minimum and maximum temperature data from 1950 – 2012 for 15 stations were used as climatic parameters. Descriptive and bivariate analyses...
July 2017
Variability of maximum temperature and its decadal anomaly over Nigeria: Possible connection with Solar and geomagnetic activity
This work investigates the variability of maximum temperature and its decadal anomaly in Nigeria and the possible role of Solar and geomagnetic activity. Descriptive, bivariate and spectral analyses, as well as Mann-Kendall trend test, were employed in analyzing the data used in this study. Temperature anomaly was computed using the base period, 1981 – 2010. Results revealed that seasonally, temperature varies...
July 2017
Estimation of depth to magnetic source bodies of Nsukka and Udi areas using spectral analysis approach
The study was aimed at estimating the depth to magnetic source bodies in Nsukka and Udi areas which falls within the Anambra basin. Aeromagnetic data were used and Spectral Analysis approach was employed in the quantitative interpretation. The total magnetic intensity (TMI) contour map which ranges from -53.1 to 133.7 nanoTesla (nT) was separated into regional and residual contour maps to produce a residual aeromagnetic...
June 2017
Omnidirectional High Reflectors using 1-D Photonic Crystals
Much interest has been paid to omnidirectional dielectric mirrors based on the 1-D dielectric multilayers because these are better than metal mirrors owing to their low optical loss, high reflectivity and high mechanical robustness. In these applications, the required position and width of the reflection band can be obtained by adjusting the layer thickness and refractive indices of the constituent materials. Here, the...
June 2017
A derivation of the Kerr metric by ellipsoid coordinate transformation
Einstein's general relativistic field equation is a nonlinear partial differential equation that lacks an easy way to obtain exact solutions. The most famous of which are Schwarzschild and Kerr's black hole solutions. Kerr metric has astrophysical meaning because most cosmic celestial bodies rotate. Kerr metric is even harder than Schwarzschild metric to be derived directly due to off-diagonal term of metric...
May 2017
Energy levels and reduced transition probabilities of 18-20F isotopes using USDA and W Hamiltonians
Energy levels for (18F, 19F and 20F) isotopes have been studied within the framework of shell model using OXBASH code. In this work, the calculations are based on the Universal Sd-shell Hamiltonian (USDA) and W Hamiltonians for proton and neutron particle orbits in SDPN model space. The calculated energy levels and reduced electric quadrupole transition probabilities B(E2;↓) are in reasonably agreement with...
May 2017
Investigation of possible cause of gravity anomalies in parts of the Niger Delta Basin, Nigeria
Possible cause of gravity anomalies in parts of the Niger Delta Basin, Nigeria was investigated using three methods of gravity data interpretation; Euler-3D deconvolution, source parameter imaging (SPI) and forward and inverse modeling. The estimated depths from the interpretation techniques used show much similarity. Quantitatively, the results obtained from the SPI method showed a minimum to maximum depth of 1264.11...
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