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

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 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 Timur’s permeability which is higher than that of the Tixier and the Coates and Dumanoir. Integration of the Achie’s equation and neutron – 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 Timur’s estimation model.

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.

This 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 2010® and OpendTect 4. 6.0® 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 “Green” 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 “Green” 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 CPillar® and the Plaxis 2D® 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 5.517×10^13N to 6.130×10^14N and that of compression ranges from 3.065×10^14N to 5 517×10^14N. 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.

Over the years, there has been significant increase in population and urbanization in Kogi State as a result of rural - urban migration. This has become a major threat to soil sustainability which is a natural non-renewable resource. The aim of this research is to carry out magnetic susceptibility mapping on the surface and subsurface soil of Kogi State using environmental magnetism techniques and geochemical analysis. The susceptibility test on rock samples and background soil samples within the study area shows an average of about 112.0×10^-5 SI. The magnetic susceptibility measurement on soil from Kogi State shows magnetic susceptibility enhancement of about (450.0 - 700.0) × 10^-5 SI. These values were dominant along the major towns, road pavements and commercial areas at the surface to a depth of about 50.0 cm in soil profiles. The 2D spatial distribution of magnetic susceptibility with depth reveals that theses magnetic grains are distributed in the subsurface as a result of anthropogenic loading. The frequency-dependence of magnetic susceptibility (?fd%) values are very low (2-10.0 %) in most of the areas on the surface soil. This values indicate that the magnetic properties are predominantly contributed by the coarse multi - domain (MD) and stable single domain (SSD) grains of anthropogenic origin. Atomic Absorbtion Spectrometer (AAS) analysis of these soil samples indicates the presence of Lead (300.0-900.0) mg/l and Cadmium (20.0-60.0) mg/l in large concentration at the surface soil in most part of the Kogi State. While Chromium show relatively low concentration on the surface soil. From the statistical correlation analysis, Lead and Cadmium show high positive correlation with magnetic susceptibility. These results suggests that the high enhancement of magnetic susceptibility on the surface and sub-surface soil in most part of Kogi State arise from anthropogenic activities rather than lithological and pedogenic processes and most likely cause by high concentration of Lead and Cadmium.

Enumabia being the only surviving river in Orokam community gave us the concern to assess the concentration of heavy metals in water and sediment in the river. 20 samples of water and Sediment were taken from four (4) different points 20 meters apart and analysed for heavy metals by the use of AA-700 Dual Atomizer Atomic Absorption Spectrophotometer in Energy Research Centre, University of Nigeria, Nsukka. In water, the concentration of Fe ranges from 0.7669 to 0.9214 mg/l, Pb ranges from 1.3300 to 1.7210 mg/l, As ranges from 0.9032 to 2.0120 mg/l, and there was no concentration of Hg, Cr and Al. The concentration of metals in the water samples are at the range of permissible limit set by World Health Organization (WHO) except Pb, and As that are fairly higher than the permissible limit. In sediment, the concentration of Fe ranges from 128.8812 to 113.9563 mg/l, Pb ranges from 0.2500 to 0.9520 mg/l, Cr ranges from 0.1240 to 0.6676 mg/l, Al ranges from 10.0000 to 16.0000 mg/l, As ranges from 0.0000 to 1.1240 mg/l, Cu ranges from 0.2420 to 0.8490 mg/l and there was no concentration of Hg. The concentration of Fe, Pb, Cr and As in the sediment exceeded the standards set by WHO. This presence could be detrimental to plant, human being and aquatic life. Since there is fast accumulation of toxic and carcinogenic metals present in the water and sediment samples collected from Enumabia River in Orokam there is need for a follow up study to determine how the human and aquatic lives have been affected.

This study used aeromagnetic data of Jema’a, sheet No.188 to estimate the geothermal energy resource potential in Jema’a Local Government Area of Kaduna State, Nigeria. The study area lies between latitude and N and longitude and E. Total magnetic intensity (TMI) map of the area was produced from the gridded data. Residual map was obtained by removing regional field from the TMI which was divided into 36 blocks for spectral analysis. The centroid depth (Z_0) was obtained by dividing the gradient of the lengthiest wavelength part of the spectrum by the wave number. The depth to top (Z_t) of the magnetic source was obtained from the gradient of high wave number portion of the power spectrum. The values of Z_0 and Z_t were used to obtain the values for depth to bottom of the magnetic source (Z_B). The geothermal gradient (dT/dZ) values were obtained by dividing by Z_B while the heat flow (q) values were obtained by multiplying dT/dZ by the constant k (2.51).The dT/dZ values obtained range from 13.560 to 4000.000?/km with an average value of and having the least (13.560 ?/km) around Kafanchan axis and the highest (4000.000 ?/km) around Sanga. The values range from 34.036 to 1004.00 mW m^(-2) with an average value of 118.089 mW m^(-2). The dT/dZ values were observed to be greater than 100 mW m^(-2) around Sanga and Andaha axes. The Curie depth (28 km) was deepest at the South-South, South-East and South-West regions. Since magnetic properties of minerals disappear at this temperature and thermal conductivity of rocks increases with depth, these areas are potential geothermal energy source.

To fully harness the increasing number of observations and variant data sets available and put them to efficient use in geological studies aimed at solving earth science-related problems, GIS technique is a veritable tool. The dynamic techniques and the complex nature of earth sciences is a serious cause for worry for geologists. In this work vertical electrical sounding (VES) was integrated with geographic information system (GIS) to delineate subsurface characteristics and evaluate groundwater potential zones in Idi Ayunre, Oluyole Local Government Area, Oyo State. The results of the VES curves obtained from the partial curve matching were used to constrain the interpretation by the computer using iteration software known as WINRESIST® and extended analysis on the data set was done using geostatistical analysis tool on archGIS 10.0®. The Root Mean Square (RMS) errors for the analysis were found to be very low with an average of 2.96% . This underscores the reliability of the analysis tool for this type of work. The area is dominated predominantly by Type-H curves which amassed twenty (20) out of the twenty-one (21) VES and one (1) VES producing a type-K curve. The VES results revealed a maximum of three geo-electric layers, viz: topsoil, weathered layer, bedrock respectively. The yields of wells dug in most of these locations may be insufficient, even for domestic use because of its relatively small thicknesses. However, at a depth of 7.8 m, a fractured zone occurs in VES 10 with resistivity value of 21.2 Om suggesting the presence of groundwater, which may be considered the main aquifer units suitable for groundwater exploration.