This paper presents an assessment of background radiation levels within the Niger Delta University campus, Bayelsa State Nigeria. A portable Geiger-Muller tube (Radiation Alert) was used to detect the background ionizing radiation within a temperature range of -100 â„ƒ to 500 â„ƒ. Results of absorbed dose rate in air in the main campus, open field and new campus varies from 104.4 nGy/h to 278.4 nGy/h with an average of 156.6 nGy/h, 34.8 nGy/h to 174.0 nGy/h with an average of 95.7 nGy/h and 69.6 nGy/h to 174.0 nGy/h with an average of 113.1 nGy/h respectively. The annual effective dose estimates ranged from 0.160 mSv/y to 0.427 mSv/y with an average of 0.024 mSv/y, 0.053 to 0.267 mSv/y with an average of 0.147 mSv/y and 0.107 to 0.267 mSv/y with mean 0.173 mSv/y in the main campus, open field and new campus respectively. The excess lifetime cancer risks ranged from 0.442 to 01.174 x 10-3 with a mean of 0.663 x 10-3, 0.146 to 0.736 x 10-3 with an average of 0.405 x 10-3 and 0.295 to 0.736 x 10-3 with average 0.479 x 10-3 in main campus, open field and new campus respectively. The estimated averages of absorbed dose rates in the air within Niger Delta University were above the world average of 57 nGy/h. Annual Effective Dose Equivalent (AEDE) are below the safe limit of 1 mSv/y for humans. The results of this study provide baseline information on the background ionizing radiation and can be referenced for future works in the area.
Rain attenuation is a major source of impairment to signal degradation at millimetre wave bands above 10 GHz. This research work determines the extent of signal degradation due to rainfall on terrestrial radio links within Minna and Lapai. The meteorological rainfall data collected from the Automatic Weather Stations installed at the Federal University of Technology, Minna, and at Ibrahim Badamasi Babangida University, Lapai, for a period of 3 years (2011-2013) were used to computate the rainfall attenuation on Microsoft Excel spreadsheets. The Lavergnat-Gole (LG) model was used for the conversion of cumulative distributions of rainfall of 5-min to 1-min integration time in Minna and Lapai respectively. The LG model was used to estimate the rain attenuation in the two stations at a frequency range of 10-18 GHz. The relationship between rain rate and specific attenuation was studied using three years rainfall data. It was observed that a power-law relationship exists between rainfall rates of different integration times. The results for the rain rate exceeded for 0.01% of time, show that the horizontal polarisation experiences more degradation than the vertical polarisation. The results also show that specific and total attenuations increase with increasing operational frequency, and are polarisation-dependent. These results would be useful for planning terrestrial radio networks within the study area.
In this research the effect of imbalance and nonlinear load on power quality was investigated via the electronic method with the aid of a Fluke 435 power quality analyser and the results obtained compared with IEEE standards. The study was carried out on 11 kV Pama feeder Kaduna state, Nigeria, which is comprised of Nassarawa, Boro1, Pama 1, Pama 2, and Pama 4 substation. The analyzed result shows an average value of 230 and 1327 times voltage dips and swells, 11.74 % harmonics current, 2.33 % harmonic voltage, 5.96% imbalance voltage and 25% imbalance current respectively. When compared with the IEEE standard limits of 5 % and 2 % harmonic current and voltage, 10 % and 5 % imbalance current and voltage, it could be seen that these results imply the presence of harmonics within the system which are fundamentally due to imbalance and non-linear load, triggering operating complications on the distribution system. These complications include load disruptions, over current, over voltage, heating, leading to forceful outage, increased power losses, faster ageing of insulations, unstable power supply, burnt cables, sockets and connectors, thus reducing capacity and ultimately resulting in premature failure of transformer.
his research presents an investigation on the shale volume effect on hydrocarbon prospectivity of Green Field within Niger Delta, Nigeria. Delineation of potential reservoirs was done with Petrel Version 2010Â® and OpendTect 4. 6.0Â® exploration and production softwares, and data obtained were quality checked to eliminate null values. Three different empirical models were used to estimate the shale volume for fifteen delineated reservoirs from the three identified â€œGreenâ€ wells. The shale volume ranges from 0.111 to 0.162 for Green 1, 0.056 to 0.092 for Green 2 and 0.007 to 0.140 for Green 3 reservoirs. An average shale volume obtained from a merger of the three models was compared to the permeability in each of the fifteen reservoirs to determine the hydrocarbon prospectivity of the wells. It was noticed that shale volume increases with a decrease in the permeability. The ratio of shale to sand ranges from 0.125 to 0.192 for Green 1, 0.059 to 0.101 for Green 2 and 0.007 to 0.111 for Green 3 reservoirs. The presence of sand in higher volume which ranges from 0.838 to 0.889 for Green 1, 0.908 to 0.944 for Green 2 and 0.900 to 0.993 for Green 3 reservoirs than shale which ranges from 0.111 to 0.162 for Green 1, 0.056 to 0.092 for Green 2 and 0.007 to 0.140 for Green 3 reservoirs and higher resistivity which ranges from 5.61 to 96.93 for Green 1, 16.01 to 103.42 for Green 2 and 14.75 to 22.17 for Green 3 reservoirs than the conductivity which ranges from 0.0100 to 0.1800 for Green 1, 0.0096 to 0.0625 for Green 2 and 0.0450 to 0.0680 for Green 3 reservoirs are some major signals confirming a substantial hydrocarbon in the reservoirs. Results from this study indicates prospective presence of fractured shale deposits in the study area. Petrophysically, subsurface reservoirs in the â€œGreenâ€ field have reasonable hydrocarbons in their pore-spaces and estimated producibility indicators are good enough to support secondary migration of the oil into the borehole, if developed.
Seismic activities leading to tremors have been a subject of interest in geophysical survey. Here in, we reported the (seismic) tectonic activities of Langbodo field, an area where tremors have occurred in the Niger Delta, Nigeria. The seismic data used in this research work were analyzed using the CPillarÂ® and the Plaxis 2DÂ® seismic softwares. These softwares are based on sensitivity, probabilistic and finite element analyses. The variation in the depth of the exploration boreholes for the five identified locations, LCT A, LCT B, LCT C, LCT D and LCT E with respective values 7525 km, 7000 km, 8000 km, 7600 km and 9000 km showed the extent to which the underlying crust can be pressurized. The seismic information from the drilled wells revealed that the tensional force created through stress ranges from 5.517 Ã— 10^13 N to 6.130 Ã— 10^14 N and that of compression ranges from 3.065 Ã— 10^14 N to 5 517 Ã— 10^14 N. The tectonic activities of each of the locations were recorded using the seismic reflection method. This study revealed that more than 50 % of the earth tremors experienced in the area were humanly triggered. Seismic records of the areas showed that human activities that result to rapid injection of fluid into the plates, if not controlled, can trigger tremors. The magnitudes of tremors that have occurred in the five identified locations LCT A, LCT B, LCT C, LCT D and LCT E are respectively 3.50 ML, 3.20 ML, 4.20 ML, 4.00 ML and 4.32 ML. This research work however concluded that the study area is likely to witness earthquakes of about 7.0 ML magnitude should explorations continue indiscriminately. Probable occurrence of earthquakes in this location can be nipped in the bud by setting up agencies that monitor and assess subsurface pressures, quantities of injected fluid, volume of extracted fluid, and the seismicity of vulnerable regions with time.
This study identified the fluid types and boundaries present within selected reservoirs in Langbodo field, using petrophysical parameters based on estimated rock properties such as porosity, permeability, irreducible water saturation, hydrocarbon saturation and bulk water volume. This was with a view to correcting the salient reservoirs heterogeneities anomalies error inherent in building of an ideal realistic reservoir models. The quality of the data obtained were checked and despiked to eliminate null values. Petrel version 2009 and OpendTect 4.6.0. Exploration and production softwares were used for the quality interpretations of data, such as lithology identification, delineation of potential reservoirs and determination of fluids and fluids contacts. Estimation of quantitative petrophysical parameters were done by inputting the data into Microsoft excel 2015 version softwares and adopting appropriate mathematical relations, such as the Tixier, Timur and the Coates and Dumanoir models for the permeability (K). Realistic estimation of the permeability was done by comparing the average of the Tixier, Timur and the Coates and Dumanoir models with each of the models. The composite model obtained, mirrors the behavior of the Timurâ€™s permeability which is higher than that of the Tixier and the Coates and Dumanoir. Integration of the Achieâ€™s equation and neutron â€“ density crossplot confirmed the presence of substantial hydrocarbon in the reservoirs, although producibility indicators revealed that the reservoirs may not be producible without enhanced oil recovery method(s). This study established that the composite model is a better representation of K in the study area because it agrees with the Timurâ€™s estimation model.
The methyl ammonium tin iodide (Ch3Nh3SnI3) perovskite nanocrystals have attracted research interest and have become a rising star in the horizon of photovoltaics due to its narrow band gap, wide visible absorption coefficient and environmental friendliness than its lead-based counterpart (Ch3Nh3PbI3) . In this article, a tin based perovskite solar cell with Zinc oxide (ZnO) and Copper Oxide (CuO) as electron transport medium (ETM) and hole transport medium (HTM) was proposed and investigated numerically using a Solar Cell Capacitance Simulator (SCAPS) tool. With appropriate parameters, a short-circuit current density (Jsc) of 27.56 mA/cm2, open-circuit voltage (Voc) of 0.82 V, fill factor (FF) of 59.32 %, and power conversion efficiency (PCE) of 13.41 % are obtained for the initial simulation. By varying the thicknesses of the absorber and electron transport layer, the optimum thicknesses were observed at 0.6 um and 0.3 um for Ch3Nh3SnI3 and ZnO with corresponding PCEs of 14.36 % and 13.42 %. Upon simulation with optimized parameters, a Jsc of 29. 71 mA/cm2, Voc of 0.83 V, FF of 61.23 % and PCE of 15. 10 % were recorded. These values are superior to those obtained without optimization which means that solar cell performance can be improved to some extent by adjusting the perovskite and electron transport layer and also, Ch3Nh3SnI3 Perovskite solar cell (PSC) is a potential environmentally friendly solar cell with considerable efficiency.
This study aimed to estimate the depth of Nickel deposit in Bakin Kogi â€“ Dangoma region, which lies between latitude 901''and 9027'N and longitude 8000' and 8017' E. The study area is located in Jemaâ€™a local government area of Kaduna state. The data was gridded using Oasis MontajÂ® to produce Total magnetic Intensity Map (TMI) of the area, and further subjected to some filtration processes in order to obtain regional and residual map of the study area. Enhancement methods such as first vertical derivative and analytic signal methods were applied to the residual map to delineate the area with potential Nickel deposit. The quantitativemethod applied were source Parameter Imaging and Euler Deconvolution to determine the various depths of Nickel deposit. From the results of the TMI map and the residual map, the magnetic intensity of the study area was between 32976.5 to 33093.3 nT and 32963.6 to 33072.9 nT respectively with Bakin kogi-Dangoma region, having the highest magnetic intensity of about 33093.3nT and 33072.9 nT respectively. The study area has a high magnetic intensity due to nickel deposit because Nickel ore environment are notable with recognizable â€œmagnetic stratigraphyâ€, prospective mafic-ultramafic contact, typified by strong magnetic contrast. Abrupt changes in the magnetic intensity infer position of the outer contact of a Nickel bearing zone. The results on the superimposed analytic map on the lineament map showed regional lineaments in Bakin kogi-Dangoma region trending NE -SW, ENE â€“ WSW and NNE â€“ SSW directions. The fractures and faults seen around the study area were strongly associated with minerals deposit. The results of Source Parameter Imaging (SPI) gave a depth of shallower magnetic sources ranges from 92.7 to 116.0 m with an average depth value of 104.35 m while the depth of deeper magnetic sources ranges from 651.2 to 976.2 m with an average depth of 813.7 m. The results obtained from 3D Euler deconvolution which was associated with dykes (SI = 1) anomaly produced at a shallower depth range of 100 - 700 m. Results obtained, shows a correspondence between the depths results obtained from the SPI and that of the Euler Deconvolution methods, indicating correlation in the magnetic depth estimation.
The study of shear rheology and molecular architecture through molecular dynamics simulation
of starch-based and gelatin-based adhesives formulated from Eleusine coracana, and cow hide
has been successfully achieved. This research has revealed that esterification of natural dextrins
with 20 % polyvinyl acetate (PVAc) will yield adhesives product with improved gel properties suitable for applications. Method of extraction, production of the adhesives by varying the
quantity of fatty acid ester and quality assessment was performed and 20% PVAc incorporation found to be suitable for application. The physical features of the macromolecular complexes
formed by the synergistic interaction of starch/gelatin and PVAc in the presence of
tetraethylamine (TEA) has been studied from the rheological point of view. On examining the impact of the molecular structure and electronic properties of the adhesive molecules on the
adhesive efficiency, quantum chemical calculations were carried out. Rheological analysis
shows the adhesives are consistent and the computed free energy obtained from molecular dynamics simulation reveals that the adhesive molecules are spontaneous, hence efficient.