Physics Memoir - Journal of Theoretical & Applied Physics
PHYSICS MEMOIR-Journal of Theoretical & Applied Physics (PM-JTAP) is a web-based peer-reviewed international journal published quarterly (March, June, September & December) by the Department of Physics, Federal University Lafia. It offers an exciting publication outlet for theoretical and applied physics.
Department of Physics, Federal University of Lafia
Silver Nanoparticles as Nano Antenna for TiO2 Activation and its Application in DSSC for Enhanced Performance
The plasmonic effects of silver nanoparticles with poly (4-vinylpyridine) as passivation nanostructure for simultaneous photon energy and electron management were investigated. SEM, UV-vis-NIR, were utilized to describe the optical and morphological properties of the prepared samples. As shown from the SEM results, the introduction of Ag@P4VP, enhances nucleation, prompting an increase in the rate of growth compared to the control. The UV-vis result demonstrates a redshift to higher wavelength, showing an increase in visible light absorption which is attributed to the intensified near field effect of the surface plasmon that emerges between TiO2 and Ag@P4VP. The functionalized samples were effectively introduced into DSSCs. The photovoltaic performances were evaluated under 100 mWcm-2 light intensity. The performance, particularly the photocurrent, and open circuit voltage of the DSSC containing Ag@P4VP NPs was remarkably enhanced by the AgNPs. The modified Ag@P4VP NPs photoanode demonstrates a short circuit current density (JSC) of 2.54 mAcm-2, a photovoltage (VOC) of 0.72 V yielding an efficiency of 1.09 %. This represents a 60.3 % enhancement in efficiency over the efficiency (0.68 %) of bare FTO without Ag@P4VP NPs.
Material Science, Photonics & Solid State Physics
Copyright (c) 2019 D. Eli, G. J. Ibeh, O. O. Ige, J. A. Owolabi, R. U. Ugbe, B. O. Sherifdeen, M. Y. Onimisi, H. Ali
Ab initio Studies of the Structural, Electronic and Mechanical Properties of Zn_1-xCr_xTe
The structural, electronic, and mechanical properties of Zn_1-xCr_xTe alloys (for x = 0, 0.25, and 1) have been investigated using ab initio plane-wave ultrasoft pseudopotential calculations based on the density functional theory (DFT). The calculations have been carried out within the local density approximation (LDA), generalized gradient approximation (GGA), and Meta-GGA (TB09) exchange-correlation functionals as implemented in the Quantum Espresso suite of codes and Elk Full-Potential Linearized Augmented Plane-wave (FP-LAPW) codes. As it is well known that LDA and GGA underestimate experimental band gaps, we made attempts to improve on the calculated band gaps using Gaussian-Perdew-Burke-Ernzerhof (Gau-PBE), hybrid functionals, and TB09. We found that the use of TB09 gives the best estimation for the electronic band gap within $\approx1\%$ error. The calculated lattice constants are all in good agreement with the experimental results. The p-type doped ZnTe with chromium (Cr) atom was also investigated (50$\%$ Cr impurity added). The Zinc-blende (ZB) CrTe shows a magnetic property, and electronic structure calculations suggest that it may have applications in spintronics. A $1 \times 2 \times 2$ super-cell (25$\%$ Cr impurity added) was created to further study the effects of impurities on the electronic and mechanical properties of ZB ZnTe. The results show changes in the lattice parameters, electronic properties, and mechanical properties. The three materials satisfy the mechanical stability conditions, which suggests that they are all mechanically stable. They are also anisotropic. Moreover, ZnTe and $\mathrm{Zn}_{3}\mathrm{Cr}\mathrm{Te}_{4}$ are ductile while CrTe is brittle.
Copyright (c) 2021 A. A. Audu, W. A. Yahya, A. A. Abdulkareem
The Effect of Active Layer Thickness on the Performance of Tin Halide Perovskite (CH_3NH_3SnI_3)
The effect of active layer thickness on the electrical properties of Tin Halide Perovskite (CH_3NH_3SnI_3) was studied using the General-purpose Photovoltaic Device Model (GPVDM) software which is an efficient tool in simulating optoelectronic devices. The simulation was based on some semi-empirical results, and the parameters were inputed to definite materials of each active layer of the solar cell while parameters such as operational temperature and suggestive resistance were based on default entry of the GPVDM simulation software. Absorber thickness was varied from 100nm to 1000nm while other parameters were kept constant. Optimum efficiency of 13.9% was obtained by absorber layer with 600nm thickness, with fill factor and open circuit voltage values decreasing as the absorber thickness increases. Results also showed that the efficiency of this device can be improved by adjusting the active layer thickness.
Copyright (c) 2021 B. A. Ikyo, F. O. Abutu, A. Itodo
Delineation of Horizontal Locations and Estimation of Depth to Magnetic Source Geometries of Dubumbali, North-East Nigeria
Identification of magnetic source geometries of causative bodies is an important procedure when prospecting for hydrocarbon signatures from aeromagnetic data. In order to achieve this purpose, three methods namely Wavelet transform technique (WTT), Fourier transform technique (FTT) and Euler deconvolution technique (EDT) were applied to the reduced to equator (RTE) magnetic data. The WTT applied to the data is based on Morlet wavelet to determine the horizontal locations of magnetic source distribution in the potential field anomalies. These anomalies are always superimposed upon one another in frequency and space domain making it difficult to identify magnetic sources which are of adjacent sources. In view of this, each of the profile data was convoluted with the continuous wavelet transform and the square of coefficients from the convoluted profiles were plotted against the pseudo-wave number. Also, a scaled normalization factor was introduced on the coefficients so that the resolution of various adjacent magnetic sources can be revealed. Depth to magnetic sources was obtained using the FTT, while EDT is used to identify and estimate depth to various magnetic source geometrics with prescribed values of structural indices ranging from 1.0 to 3.0. From this analysis, we have been able to use both WTT and EDT to identify various magnetic source geometries which are attributed to volcanic intrusive rocks found to be predominant in the area while the results of depth estimate using both FTT and EDT ranges from 250 m to 1800 m. The study concluded that the methods are not only useful in the identification and estimation of source geometries due to magnetic anomalies alone, their combinations have served as a tool for identifying hydrocarbon signatures within the study area.
Geophysical, Space and Atmospheric Physics
Copyright (c) 2021 T. O. Lawal, J. A. Sunday, S. O. Issa, K. Fawale, L. I. Nwankwo
Characterization and Optimization of Transparent and Conductive ITO Films Deposited on n and p-types Silicon Substrates
The characteristics of enhanced transparent and conductive indium tin oxide (ITO) films on n-type and p-type Si substrates grown by radio frequency (RF) magnetron sputtering were investigated. The structural, optical and electrical properties of the films after annealing at different temperatures ranging from 300°C to 600°C in air were studied. X-ray diffraction (XRD) analysis reveals an amorphous structure for the as-deposited films of both the n-type and p-type Si. The annealed films exhibited a polycrystalline nature with preferential peaks orientation along (222) and (400) crystalline directions. Atomic force microscope (AFM) results indicate smooth surface morphology with increasing roughness as the annealing temperature increases. The surface roughness of the ITO films on the p-type Si was high (6.65 nm) at 500°C and very good microstructures on both Si types were obtained at 500°C. Optical transmittance is enhanced from 89.1 % for the as-deposited film to 95.7 % for film annealed at 500°C in the visible range. ITO films on n-type and p-type Si demonstrate a substantial reduction in their electrical resistivity and sheet resistance with increasing annealing temperature. The ITO/p-Si structure exhibits a low resistivity of 2.45 × 10-5 ?-cm compared to 7.46 × 10-5 ?-cm for ITO/n-Si structure. The films performance showed a figure of merit of 14.68 × 10-3 ?-1 for ITO/n-type Si and 44.74 × 10-3 ?-1 for ITO/p-type at 500°C indicating that the optimized ITO films on p-type Si can be a promising ITO/p-Si heterojunction for silicon solar cells.
Copyright (c) 2020 A. K. Isiyaku, A. H. Ali, S. G. Abdu, M. Tahan, N. A. Raship, A. S. Bakri, N. Nayan
An Assessment of Rainfall Attributes and Onsets-Cessations Dates Effective for Cropping in Lafia, Nasarawa State, Nigeria
Rainfall affects almost all human lives, significantly in diverse fields like agriculture, business, health, transportation and tourism. Amongst the main endeavours engaged by man, agriculture is the main stake for man’s source of livelihood. Most people are not aware of the attributes of rainfall peculiar to their surroundings, as such embarked on agricultural activities through ``try by error" and are faced with challenges due to the unstable nature of weather. Weather does disappoint most people that are into farming because rainfall varies in the study area. This study aimed at assessing Lafia rainfall attributes and the determination of its onset-cessation dates effective for cropping. Eleven years rainfall data of Lafia was collected for the study. The analysis was carried out using Excel tool and Mann Kendall analytical approach with the aid of Xl statistical software in the description of Lafia rainfall attributes. The study reveals a less stability nature of rainfalls at a value greater than 40, and a fluctuating onset dates between April and May with drought and dry spell occurrences in each of the growing seasons were recorded. The study therefore concluded that, there exist a less stable rainfall amount and a highly stable rainfall frequency of occurrences; all these affects food crops production and its output as the average rainfall amount recorded is (1371.2 mm) while the average number of rainy days in the study was (95 days). It is therefore recommended that other researchers should carry out an empirical study on the severity of drought and dry spell in the study area.
Copyright (c) 2020 J. T. Yashim, A. F. Abdussalam, I. I. Abbas
Stitched Transmission Line for On-Body Communication Systems
In this paper we report the use of a stitched transmission line for on body communications. The stitched transmission line was designed as a two wire braided coaxial cable using CST Microwave Studio Suite®. The constructed line is made up of a copper inner conductor surrounded by a polyethylene tubular insulating layer from a stripped RG174 braided coaxial cable. For shielding purpose, the structure is stitched onto a denim material with a conductive thread with the aid of a novel presser foot. To explore its suitability for on-body communications, the stitched transmission line was placed at approximately 5mm from the human body at the left hand side of the chest just below the nipple area and measurements were taken with an Anritsu MS46524A7GHz Vector Network Analyser (VNA) for a frequency range of 0.04 – 4GHz, with measured results demonstrating that the stitched transmission line can be used for on-body communications.
Copyright (c) 2020 I. H. Daniel, N. Kure, M. U. Benedict, S. H. Sarki, A. A. Kassimu
First Principle Study on the Structural Optimization and Electronic Properties of Methylammonium Bismuth Bromide and Methylammonium Galluim Bromide
Ab initio calculations for the structural optimization, and Band Structure analyses of CH3NH3BiBr3 and CH3NH3GaBr3 (having 8.33\% dopant replacement percentage each) as possible replacements for the Lead based perovskite CH3NH3PbBr3 were done in this work using Perdew–Burke–Ernzerhof functional of Density Functional Theory as implemented by FHI-aims Code. Molecular visualizations and crystal structures were rendered using JMOL. Optimized lattice constants were calculated for CH3NH3BiBr3 and CH3NH3GaBr3 to be 9.10 Ao and 8.27 Ao respectively, and The Lowest Unoccupied Molecular Orbital (LUMO), Highest Occupied Molecular Orbital (HOMO) and calculated band gap, Band Structure and Density of States (DOS) plots were made to analyse the band structures of these crystals and they were found to be metallic with a band gap of 0.00018636 eV and 0.00022286 eV forCH3NH3BiBr3 and CH3NH3GaBr3 respectively.
Copyright (c) 2019 S. G. Abdu, A. Shuaibu, M. Aboh, M. S. Abubakar
Radiometric Evaluation of Naturally Occurring Radionuclides in Mining Sites across Mararraba-Udege of Nasarawa State, Nigeria
This study evaluates the existence of radionuclides in some mining sites in Mararaba-Udege using a hand held interceptor TM–Thermo scientific radio nuclear identiFINDER designed for in situ operation. The device is placed in contact with the soil and the radionuclides in the soil are detected as well as the contribution of those radionuclides to the background radiation. Gamma Activity (mRem/yr), possible radionuclide present and their trust levels, Exposure Dose Rate ($\mu$Sv/hr), Absorbed Dose Rate (nGy/hr), Effective Dose Rates (mSv/yr) and Excess Lifetime Cancer Risk, were determined. Results obtained shows that the gamma activity level ranged from 0.955 to 1.260 mrem/hr with the mean of 1.1245 mrem/hr. Exposure dose rate of the study area ranged from 9.55 to 12.6 $\mu$Sv/hr with the mean of 11.245 $\mu$Sv/hr. The local miners in the study area are subjected to absorb dose rate ranging from 9553 to 12600 nGy/hr with the mean value of 11245 nGy/hr. Effective dose rate of the area under investigation were ranged from 1.605 to 2.117 mSv/yr with a mean of 1.889 mSv/yr. The excess lifetime cancer risk of the area ranged from $5.618 \times 10^{-3}$ to $7.408 \times 10^{-3}$ with the mean of $6.629 \times 10^{-3}$. The result also shows that there is Palladium (${}^{103}$Pd), Americium (${}^{241}$Am), Iodine (${}^{125}$I), Uranium (${}^{235}$U), Cadmium (${}^{106}$Cd), Selenium (${}^{75}$Se) and Cobalt (${}^{57}$Co) in significant percentage. From the findings presented, it can be concluded that natural radionuclides pollution in the mining area is an issue of health concern.
Copyright (c) 2019 Rilwan U., Umar I., Abdullahi H. A., Ngari A. Z., Aboh H. O.
Evaluation of Radiological Hazard Indices and Environmental Safety in Soil Samples from Different Source Term Within the Tributaries of Awba Dam in the University of Ibadan
Artificial and Natural radionuclides exist in environmental materials such as water, soil, rocks, and plant as well as in animals and human body tissues. Therefore, human being and environment are at constant radiation exposure. Regarding this, the present study aimed to determine the specific activities of radionuclides and perform the risk assessment study to establish if there was a potential threat posed by radionuclides to humans and aquatic life in Awba dam, the University of Ibadan, due to untreated effluents discharge from the hall of residences. In this study, natural and artificial radioactivity concentrations were determined in soil samples from different source terms located along the banks of the input water discharge points into Awba dam, University of Ibadan, were collected and analyzed for natural radioactivity level using gamma-ray spectroscopy. A total of Twenty-eight sediment samples were collected for the measurement. Samples were collected one after the other along the banks of the source point. Prior to the collection of all the samples from each source point, both analogue and digital survey meter were used to ascertain the level of radiation in their immediate environment. The prepared sample was sealed and stored for a minimum of thirty-days to allow for radium equilibration with daughters nuclide. The range of the activity concentration due to ${}^{40}K$ was 2.023 to 1194.1 $BqKg^{-1}$ while those for ${}^{238}U$ and ${}^{232}Th$ were respectively 2.12 to 21.82 and 0.91 to 31.10 $BqKg^{-1}$. The total absorbed dose rate of the three radionuclides are $0.08-8.54$, $1.0-10.01$, $0.26-10.56$ $nGy^{-1}$ respectively, for the result shows that the total concentration of ${}^{232}Th$ is much higher than that of ${}^{238}U$ while ${}^{40}K$ leads the table of radioactivity concentration. The entire soil sample from different source term does not pose any significant radiological threat to the general public, and the activity concentration of the radionuclides in the sediments are equally low. No artificial sources of radionuclides were detected in any of the soil and sediment samples of the Dam.
Copyright (c) 2019 Lawal R. S., Aisida S. O., Umaru I., Mundi A. A., Shehu M. S.
Approximate Solutions of the Effective Mass Klein-Gordon Equation for Unequal Potentials
Using a suitable approximation scheme to the centrifugal barrier, we solved the 3-dimensional Klein-Gordon equation for effective mass potential under unequal scalar and vector Coulomb-Hulth?n potential in the framework of parametric Nikiforov-Uvarov method. The effects of the screening parameter, the effective masses and the potential strengths on energy were graphically and numerically studied in details. It is noted that the relativistic energy of the Klein-Gordon equation under unequal scalar and vector Coulomb-Hulth?n potential is highly bounded
Theoretical / Mathematical & Computational Physics
Copyright (c) 2019 C. A. Onate, O.O. Ogunlesi, O. M. Odeyemi, O. E. Odeyemi
Integrated Geophysical and Geotechnical Pre-foundation Assessment of Proposed Baze University Teaching Hospital Abuja, Nigeria
This paper presents the result of the geophysical and geotechnical assessment of the proposed site of Baze University Teaching Hospital in Abuja, Nigeria. The geophysical investigationwas carried out using Vertical Electrical Sounding (VES) Resistivity method with Schlumberger array. The geophysical results revealed four distinct subsurface geological layers that are made up of lateritic topsoil, weathered layer, fractured basement and fresh basement.The natural moisture contents of the soil samples are found to range from 10.8% to 12.6%. The results of compaction test give a maximum dry density between 1.8 mg/m3 to 1.97 mg/m3 while its optimum moisture contents are between 10.3% and 18.3%. The Atterberg limit and plasticity index are also estimated along with analysis of grain size.The grain size analysis showed that for a sieve size of 200B/S or 0.075mm, the percentage passing ranged from 41% to 52%, while the linear shrinkage is found between 18.6% and 23.3%.The results were compared with the 1997 Federal Ministry of Works and Housing (FMWH) construction standards, which are then used as guidelines for thorough engineering foundation. The geophysical result shows that the study area has a shallow depth to basement which makes the site suitable for the proposed Baze University Teaching Hospital while the geotechnical result shows the lateritic topsoil contains high clay content which must be excavated and replaced with a good fill material before the construction take place to avoid swelling of the foundation material.
Copyright (c) 2019 Muyideen K. Salami, Tobenna Offodile, Taiwo Adewumi, Joseph Asare, Oluwaseun K. Oyewole
Radiation Exposure Levels Associated with Tin Mining Sites around Toro Area, Bauchi State, Nigeria
The concentrations and distribution of natural radionuclides in soils of tin mining sites around Toro and environs, Bauchi Nigeria were investigated. Previous studies revealed that the mining activitiesenhancedthe risk of radiation exposure.Twenty six soil samples were collected from eight sites (locations) to measure their natural radioactivity concentrations due to natural radionuclides (226Ra, 232Th and 40K) using gamma spectrometry techniqueconsistof Thallium activated Sodium Iodide (NaI (Tl)) detector. The mean activityconcentration valuesfor 226Ra, 232Th and 40K are38.78 ± 3.13Bq/kg, 105.77 ± 2.46Bq/kg and 491.89 ± 7.85Bq/kg respectively. The mean absorbed dose rate was found to be 102.24 ± 3.28 nGy/h,which is above the safety limit. To evaluate the radiological hazard of the natural radioactivity, the radium equivalent activity, the hazard index (external and internal hazard index), the absorbed dose rate and the effective dose rate were been calculated and compared with internationally recommended values. The radium equivalent activity values of all samples are lower than the limit of 370Bq/kg except at location DGJ which has the value 442.46 Bq/kg. Also, the values of the external and internal indices are less than unity, except at location DGJ which has value greater than unity. The mean annual effect dose ratewas 0.212mSv/y and is less than 1mSv/y upper limit recommended for the public by International Commission on Radiological Protection (ICRP).
Copyright (c) 2019 G. G. Ibrahim, Umar S. Aliyu, M. U. Najib, A. M. Hamza
Variations of GPS-TEC at an African Low Latitude Station during Geomagnetic Disturbances
Global Positioning System (GPS) measurements have been used to investigate the storm-time seasonal variations of the total electron content (TEC). The selected storm events are all moderate (-100nT < Dst ? -50nT) and occurred at different seasons between the year 2002 and 2006 during the descending phase of solar cycle 23. The GPS measurements were obtained from the International GNSS Services (IGS) database for the receiver located at Lusaka (Geog. Lat. 15.43oS, Long. 28.31oE, -26.27o dip), Zambia, a low latitude station in the African region. Analysis of the TEC data shows significant differences in the TEC variations during the storm events with noticeable local time and seasonal components. In most of the storms considered, positive storm effect was observed during their main phases with magnitudes and durations that differ seasonally. The positive phase is most prominent for storms that have their main phase during the daytime particularly in winter and equinoxes, while in summer, the positive phase is more noticeable between the pre-midnight and early morning period. The trend of storm-time TEC variations are the same for equinoxes and winter, with a consistent positive phase during the daytime and negative phase at nighttime. The TEC variations, however, differ in magnitude and duration. The response of TEC to the geomagnetic storms also presents a summer/winter and autumn/spring asymmetry. General observation shows a long lasting negative phase in daytime than at nighttime during summer; while it shows a fairly consistent behaviour with a positive and negative phase observed during the daytime and nighttime respectively, in winter. The average storm-time behavior observed at different seasons may suggest a way to improve the storm-time prediction of ionospheric models which have limited success in estimating short-time ionospheric dynamics.
Copyright (c) 2019 S. J. Adebiyi, S. O. Ikubanni, B. O. Adebesin, B. W. Joshua, B. J. Adekoya
Structural and Electronic Properties of Delafossite CuGa1?xMnxO2(X=0.5) Nanocomposite: A First Principle Study
In this paper, we investigate the structural and electronic properties of manganese doped delafossite CuGaO2 nanocomposite using first principle study based on density functional theory (DFT). The generalised gradient approximation (GGA) as parameterized by Perdew-Burke-Ernzerhof (PBE) has been used for both the undoped and doped systems. The crystal structure of the material does not change after manganese doping. Our calculation shows that the doped structure is stable. However, the results reveal that the 50% Mn doping decreases the band gap of the delafossite CuGaO2 system by 0.5 eV. The charge density distributions for the undoped CuGaO2 and CuGa1-xMnxO2(x=0.5) are almost the same.
Copyright (c) 2019 S. S. Alhassan, A. Shuaibu, M. Y. Onimisi
A Review on Environmental Radioactivity Measurement and its Impact on Human Health
Natural radioactivity in drinking water sources, no doubt poses serious contamination hazards. Assessment of its level in drinking water, therefore, provides useful information on potential unwanted radiation exposure to humans. To assess the effects of natural radionuclides in the environment, analysis is carried out on samples from the environmental media such as water, soil, and species using different radiation detection techniques. This article reviews some of such studies with a view of gathering vital information on the recently used techniques, discusses current situations and give highlights of recent findings.
Copyright (c) 2019 B. G. Muhammad, A. A. Bello
Effects of Deposition Time of ZnS Thin Film on Optical and Morphological Properties of ZnS Deposited by Chemical Bath Deposition Method for Photovoltaic Application
The effect of deposition time was investigated on optical and morphological properties of synthesized ZnS thin film. ZnS thin films were prepared at different temperatures and different deposition period of 1 hour, 2 hours and 3 hours onto the glass substrates by chemical bath deposition technique at a deposition temperature of 50 °C. The precursor was prepared using a mixed aqueous solution of zinc sulphate as a source of zinc and thiourea as a source of sulphur while ammonia serves as complexing agent. After the deposition, the thickness of the samples was determined using the double weighing method, the morphological and optical properties of the films were determined using Scanning Electron Microscope (PHENON WORD), UV-visible double beam spectrophotometer (ATICO) respectively. The result shows that transmittance spectral increases in the visible region of wavelength 400nm to 800nm and decreases in the infrared region at above 800nm wavelength. The transmittance spectra of the film deposited for 2 hours shows the highest value of 70% while the films deposited for 1 hour and 3 hours have the transmittance of 55% and 37% respectively. The extrapolated optical band gap energy for the film deposited is between 3.6-3.8 eV. The microstructural images of all the samples were rough and the grains were dense. The samples deposited for 3 hours and 2 hours are more clustered and smoother compared to the sample deposited for 1 hour.
Copyright (c) 2019 Y. I. Bolanle, R. A. Babatunde, O. O. Adegboyo
Impact of Rainfall Variability on Yam (Dioscorea Spp) Yield in Lafia Local Government Area of Nasarawa State, Nigeria
Rainfall variability influences almost all human endeavours, most especially in the field of business, health, transportation and tourism, and most importantly in the aspect of agriculture. Agriculture is the main activity engage by most developing countries even with the general threat to food security globally. This study centered on examining the impacts between rainfall variability and yam yield for the period of eleven years covering from 2006- 2016 in Lafia Local Government area. Eleven years (monthly/annual) rainfall data with annual yam yield data of Lafia Local Government were collected for the study. The analysis was carried out using E-Views 9 statistic for the trends and impacts analysis while Mann Kendall analytical approach was also used with the aid of Xl statistical software/tool for an in-depth regressing/coefficient of determinants analysis and variance of regression models analysis in the study. The result shows that rainfall variability has a significant impact of about 79% over yam production output (yield) and the remaining 21% is contributed by other factors than rainfall. The study also reveals a variability level of rainfall and yam output of Lafia at 10% and 37% coefficient of variance for a low and moderate extent of variability respectively. It was also concluded that there exists a strong positive impact of rainfall variability over yam-tuber output for the period under study. It is therefore recommended that other researchers and relevant bodies should carry an empirical study on the impacts of total land area for yam cultivation, soil fertility and socio-political factors to yam tuber production output (yield) in the study area.
The Performance of Dye Sensitized Solar Cell Fabricated Using Dye Extracted from Irvingia Gabonensis Leaves
The performance of dye sensitized solar cell (DSSC) fabricated using dye extracted from Irvingia gabonensis leaves was analyzed in this work. Ethanol was used as the extracting liquid. The method employed is Sol-gel technique. Fluorine Tin oxide (FTO) was used as electrode while Titanium dioxide (TiO2) was used to absorb the dye. The counter electrode was coated with carbon. The elemental composition of the Titanium dioxide film deposit was investigated using Energy Dispersive X-ray (EDX), solar simulation was carried out using a Newport solar simulator and the absorption spectrum (light absorbance) of the chlorophyll dyes were measured using UV-1800 series spectrophotometer. The dye has band gap of 1.2 eV and the plot of current density versus voltage (I-V curve) revealed that the open circuit voltage and short-circuit current density of the fabricated solar cell were 0.121 V and -0.0921 mAcm-2 respectively. The overall conversion efficiency of the cell is 8.53 × 10-5 % while the fill factor (FF) is -7.6589406. Though the overall conversion efficiency of the fabricated DSSC is relatively low, it can be used in poultry houses where great infrared radiation is needed since the transmittance of the dye at near infrared region is high.
Copyright (c) 2019 I. E. Ottih, E. I. Achuka
Thermoelectric Transport Properties of Ternaries Mixed Chalcogenide Bi2Te2 X (X= S And Se): A First Principle Study
Thermoelectric transport properties of materials that possess a unique nature are of interest for many technological applications such as thermoelectric refrigerators and thermocouple. In this study, we have reported a theoretical investigation within the density functional theory (DFT) based on first principle calculation of the electronic and thermoelectric transport properties of ternary mixed chalcogenides Bi2Te2X (X=S and Se). The spin-orbit coupling (SOC) within the linear density approximation (LDA) is included during the electronic properties investigation. A semi-classical Boltzmann theory within a linear response method has been applied in investigating the transport properties of these compounds. The two compounds are found to have differences, both in electronic and transport properties despite their structural similarities. Results obtained from this study have been discussed and compared with a number of theoretical and experimental results of compounds with similar nature.
Copyright (c) 2019 Yusuf Z. Abdullahi, Alhassan Shuaibu, Yakubu A. Tanko, Oyedare P. Olusola, Odelami A. Kafayat
Calculation of the Excitation Functions of Alpha-Induced Reaction for the Production of 123,124I from Threshold to 40 Mev
EXIFON 2.0 code has been used to calculate the (?,n) and (?,2n) reactions of 122Sb for the cyclotron production of 123,124I which have application in positron emission tomography imaging. For both reactions, the threshold for the reaction obtained from the evaluation compared well with measured values. Results obtained shows good agreement with measurements from EXFOR. It was observed that there is a need for optical model contribution to the pre-equilibrium mechanism of EXIFON at 16MeV for (?,2n) and 27MeV for (?,n) reactions. However, the results show good agreement with available measured data at lower energy level.
Copyright (c) 2019 Ahmad Danladi Adamu, Nicodemus Kure, Emmanuel Joseph Adoyi, Isaac Daniel Hyuk, Bello Ayodeji Ibrahim
Effects of Annealing Temperature on Optical and Electrical Conductivity of (80 nm ITO)/(100 nm ZnO) Transparent Conducting Oxide Multilayer
Conductive and transparent multilayer films consisting of two layers (ITO/ZnO) have been fabricated as Transparent Conducting Oxides (TCO). 100 nm ZnO film was deposited on 80 nm Indium Tin Oxide (ITO) film by thermal evaporation in a residual pressure of 10-5 Torr and the films were annealed at 400 °C and 500°C for 60 minutes in Tubular furnace. The as-grown and the annealed films were characterized using Powder x-ray Diffractometer (PXRD) for the phase identification of the materials and UV-Visible Spectrophotometer for the photometric measurements. Beer's Lambert equation was employed to estimate the absorbance of each film under study. Four point probes based instrument was used to measure the average resistance of the films. The sheet resistance of the film was calculated from the electrical resistance of the material. The results revealed that the transmittance spectra of (80 nm ITO/100 nm ZnO) multilayer films depend strongly on the annealing temperatures and the wavelength. Optical transmittance of about 95% was estimated for the 400 °C annealed film in the ultraviolet and visible region and relatively decreases towards the infrared region of the solar spectrum. The average electrical conductivity of 14000 (ohm.cm)-1 was also estimated for the 400 °C annealed film. Rhombohedral centered and hexagonal lattice structures were identified for the ITO and ZnO films respectively. 80 nm ITO/100 nm ZnO multilayer films annealed at 400 °C is hereby recommended as a good TCO for solar cells applications.
Copyright (c) 2019 Physics Memoir - Journal of Theoretical & Applied Physics
Line Fed Triangular Microstrip Patch Antenna for Bluetooth Application at 2.45GHz
Microstrip patch antennas are very popular nowadays because they offer attractive performance and are portable. Microstrip antenna with different shapes has been designed. However, the triangular shape has not been well researched. Hence, in this paper, a line fed Triangular Microstrip Patch Antenna (TMPA) for Bluetooth Application at 2.45GHz was investigated using CST microwave studio. Two different substrates were considered for which after optimization, Duriod 6010 gave the smallest effective length compared to Rogers RT, but had the least directivity of 4.47dBi, gain of 3.52dB, VSWR of 1.02 and bandwidth of 33MHz. Whereas, Rogers RT gave the best directivity of 6.29dBi, gain of 5.55dB, VSWR of 1.08 and bandwidth of 42MHz. Nevertheless, the advantages offered by Rogers are at the expense of enlarged patch length. Similarly, the proposed antenna resonated at 2.45GHz with sufficient bandwidth compared to the conventional patch antennas. This makes it suitable for use in S band (2400-2485MHz) for Bluetooth application.
The Thirty Years Trend Analysis of Harmattan Season Visibility and Temperature in Sahel Zone of Nigeria
Climate anomalies have created short-duration climatic oscillations as against the normal cycle and this has posed and is still posing a threat to life and properties in Nigeria. A special climate change unit was created by Nigerian government in 2006 to address this problem. In this study, the meteorological data were obtained from National Oceanic Atmospheric Agency-National Climate Data Centre (NOAA-NCDC) for Sahel zone of Nigeria to analyse the long-term (1988-2017) trend and variability of visibility and temperature. The result reveals that visibility exhibited a decreasing trend while temperature shows an increasing trend over 30-years period. The 30-years seasonal mean visibility is 9.2±2.39, km while the corresponding temperature is 25.12±3.87oC respectively. Decade analysis revealed that the most obvious changes happen during the third decade. Standardize anomaly chart of visibility and temperature also reveal that changes in visibility and temperature are consistent over the study period. A simple regression analysis at p< 0.05 significant level were conducted with visibility as dependent and temperature as independent variables. The results show that the magnitude and nature of the relationship between temperature and visibility depend upon time. However, the trend line is consistently exponential. By dividing the data into ten years interval a much stronger and more significant relationship were obtained.
Trace Elements Analysis of Some Herbal Plants with Antimalarial Potency in Ibadan South-West Local Government Area of Oyo State
Trace elements concentrations in twelve herbal plants with antimalarial potency in Ibadan South-West Local Government Area of Oyo State were studied using Atomic Absorption Spectroscopy (AAS) technique. The study was aimed at determining the qualitative and quantitative trace elements in these plants. Leaves, stem barks and corm of selected plants were analyzed for their trace elemental contents. The plant samples were found to contain essential trace elements such as Mn, Cu, Zn, Fe, Cr and Ni which are well known for their important roles in formulation of herbal drugs as well as toxic elements such as Cd and Pb. The concentration of Mn ranged from 0.10±0.00 mg/kg in Khaya grandifoliola to 2.16±0.00 mg/kg in Morinda lucida while for Zn, highest concentration of 0.31±0.01 mg/kg was obtained in Lawsonia inermis. Fe concentration ranged from 0.77±0.03 mg/kg in Curcuma longa to 7.22±0.01 mg/kg in Azadirachta indica while for Cr, it varied between 0.01±0.03 mg/kg and 0.13±0.01 mg/kg for Alstonia boonei and Enantia chlorontha respectively. Ni concentration varied from 0.22pm 0.01 mg/kg (Mangifera indica) to 0.33±0.02 mg/kg (Enantia chlorontha) while Pb varied between 0.39±0.05 mg/kg (Nauclea latifolia) and 0.76±0.15 mg/kg (Enantia chlorontha). Cu and Cd levels were below detection limits [Cu (0.005 mg/kg and Cd (0.01 mg/kg)] of the spectrophotometer used. The concentrations of the trace elements in the samples were lower than the permissible limits set by World Health Organization (WHO). The study has shown that the herbal plants can provide antimalarial potency without leaving deteriorate effects of consuming some harmful trace elements. The study could serve a baseline for further researches on the subject matter in future.
Determination of Electronics and Molecular Structure of Nateglinine Anti-Diabetic Drug Using DFT
Diabetes mellitus is a metabolic disease characterized by high blood glucose level and result from defects in insulin secretion, insulin action or both. Gaussian 09 software package which uses Density functional theory was used to search for conformers, optimize the structure, and calculate the electronic properties of the Nateglinide anti-diabetic drugs. It was found that C20-C18-C16-H45 isomer has the lowest energy of -2762.448518 eV and transition energy of 400.8615826 eV. Also it was found that the dipole moment increases as the basis set increases while the total energy decreases. Information on bond lengths, bond angles and dihedral angles of the optimized structure were reported. It was observed that the strongest bond is O3-C17 with a bond length of 0.9728 and the weakest bond is C15-C16 with a bond length of 1.5511Å. Finally, the Homo-Lumo formations reveal that there are more free non-bond electron in the homo site due to higher ionization potential.