Cadmium geochemistry and groundwater pollution status evaluation using indexing and spatial analysis for Keffe community and Environs Sokoto Basin, North Western Nigeria

Representative groundwater samples were collected from the Kaffe community and environs to evaluate the concentrations and geochemical constraints for mobilizing cadmium (Cd) and selected heavy metals. Field-based in-situ measurements of physicochemical parameters were combined with Atomic Absorption Spectrophotometer analysis of dissolved elemental concentrations. Pollution indices (i.e. heavy metal pollution index; HPI, heavy metal evaluation index; HEI, contamination degree; Cd, metal index; MI, synthetic pollution index; SPI, ecological risk index; ERI and Nemerow index; NI) evaluations highlighted the levels of heavy metals in the groundwater. Cadmium and iron (Fe) concentrations exceeded the recommended limits in 97% of the analysed samples, with an average pH of 6.3. Strong positive correlations were observed between cadmium and the computed pollution indices (p 0.774 to p 0.100), suggesting significant Cd pollution of the groundwater. Components analysis grouped Cd, Fe, and the pollution indices in the first PC. This was favourably compared to the correlation analysis result. Cluster analysis categorized Cd, Zn and pH in the first cluster consistent with the suggested dissolution and enrichment of Cd and Zn in the groundwater under similar geochemical conditions. The study area is medium and moderately polluted based on HPI, HEI, Cd, and NI

Mediating effect of positive psychological strength, study skills on examination anxiety among nigerian college students

Examination plays a vital role in the present contemporary educational setting as well as serving as an indicator and yardstick to place students in relation to their examination scores after they undergo the examination. However, students at different educational levels experience examination anxiety, which can interfere with making right decisions either before or during examinations and is considered to be a phenomenon associated with low examination scores. Therefore, the present research study was aimed at determining the mediating effect of positive psychological strengths between study skills and examination anxiety among Nigerian college students. The study employed survey research on 315 Nigerian college students. The result of the path analysis shows that study skills (SSK) have a significant and direct relationship on examination anxiety. The mediation between positive psychological strength (PPS) and examination anxiety is identified as being effective and significant. Therefore, positive psychological strength (PPS) acts as an effective mediator towards examination anxiety

Optimization and Non-Linear Identification of Reservoir Water Flooding Process

In this study, dynamic optimization and identification of petroleum reservoir waterflooding using receding horizon (RH) principles was examined. Two forms of the strategy were compared on a realistic reservoir model. Sequential quadratic programming (SQP) was applied to optimize net present value (NPV) using water injection rates as the variables. MRST from SINTEF was used for the reservoir modeling. The identification of the reservoir was performed using nonlinear autoregressive with exogenous input (NARX) neural network from MATLAB. Data for the network training and validation was obtained by carrying out a numerical experiment on a high fidelity model of the reservoir. This model was developed with Eclipse Reservoir Simulator from Schlumberger. From the results obtained, moving-end RH gave a higher NPV than fixed-end RH with a margin of $0.5 billion. The identification algorithm was very much effective and near perfect for the studied reservoir

Modeling and Simulation of Hemihydrate Phosphoric Acid Plant

In this paper, wet hemihydrate phosphoric acid process was modeled and simulated using ASPEN PLUS using properties of Sokoto Phosphate Rock to characterise the basic raw material. The process consisted of the reaction section, filtration section, and purification unit. Results of the simulation showed that the model developed in this study described the behavior of a real plant. Sensitivity analyses for the fundamental parameters were performed using the model. From the results of the sensitivity analyses, it was found that the temperature and pressure of the flash separator are the main factors that affect the purity of wet process phosphoric acid. At a temperature above 400°C, the purity of the phosphoric acid is maintained at 100%. This value changes at temperatures below 80°C where the phosphoric acid purity is maintained at 74%. This indicates that the purity of the acid increases with increase in flash separator temperature. The purity of the phosphoric acid varies inversely with the pressure of the flash separator. The purity of the phosphoric acid is about 84% at 0.5 bar. It decreases gradually with increase in pressure

Enhancing Oil Recovery through Waterflooding

Waterflooding is a simple and cheaper means of improving oil recovery from a reservoir by injecting water into the reservoir. Economic considerations suggest injection and production wells must be optimally placed considering reservoir geology, fluid properties, and well orientation. This study focuses on the effects of well placement and orientation on the performance of waterflooding process. The reservoir has a dimension of 2500 ft by 2500 ft by 150 ft. It is homogenous in porosity and heterogeneous in permeability. The performances of three cases considered in the study were evaluated and compared. Water production rates, bottom hole pressure limits for producer wells, well water cut and net present value (NPV) over the entire production period were considered in evaluating their performances. Reservoir modeling and simulation were carried out using MATLAB Reservoir Simulation Toolbox (MRST). It was verified from the investigation that Case III has a maximal production rate of 1,110,188.6 stb/day (stock tank barrel per day), decreasing to 11,005 stb/day after a span of 1400 days with a pressure decrease. Consequently, it was considered a better choice in terms of well placement. It was also estimated to have a maximal Net Present Value of 19.8 billion dollars, which makes it economically viable

Short tandem repeat (STR) based genetic diversity and relationship of indigenous Niger cattle

The diversity of cattle in Niger is predominantly represented by three indigenous breeds: Zebu Arabe, Zebu Bororo and Kuri. This study aimed at characterizing the genetic diversity and relationship of Niger cattle breeds using short tandem repeat (STR) marker variations. A total of 105 cattle from all three breeds were genotyped at 27 STR loci. High levels of allelic and gene diversity were observed with an overall mean of 8.7 and 0.724 respectively. The mean inbreeding estimate within breeds was found to be moderate with 0.024, 0.043 and 0.044 in Zebu Arabe, Zebu Bororo and Kuri cattle respectively. The global F statistics showed low genetic differentiation among Niger cattle with about 2.6 % of total variation being attributed to between-breed differences. Neighbor-joining tree derived from pairwise allele sharing distance revealed Zebu Arabe and Kuri clustering together while Zebu Bororo appeared to be relatively distinct from the other two breeds. High levels of admixture were evident from the distribution of pairwise inter-individual allele sharing distances that showed individuals across populations being more related than individuals within populations. Individuals were assigned to their respective source populations based on STR genotypes, and the percent correct assignment of Zebu Bororo (87.5 to 93.8 %) was consistently higher than Zebu Arabe (59.3 to 70.4 %) and Kuri (80.0 to 83.3 %) cattle. The qualitative and quantitative tests for mutation drift equilibrium revealed absence of genetic bottleneck events in Niger cattle in the recent past. High genetic diversity and poor genetic structure among indigenous cattle breeds of Niger might be due to historic zebu–taurine admixture and ongoing breeding practices in the region. The results of the present study are expected to help in formulating effective strategies for conservation and genetic improvement of indigenous Niger cattle breeds

Morphological assessment of the Zebu Bororo (Wodaabé) cattle of Niger in the West African zebu framework

A total of 357 adult cows and 29 sires belonging to the long-horned Niger Zebu Bororo cattle population were assessed for 13 body measurements and 11 qualitative traits. Data were jointly analysed with 311 cows and 64 sires belonging to other four West African zebu cattle populations, sampled in Burkina Faso and Benin, representative of both the short-horned and the long-horned West African zebu groups using multivariate statistical methods. Besides the other long-horned zebu breed analysed (Zebu Mbororo of Burkina Faso), Zebu Bororo cattle tended to have the highest mean values for all body measurements. Mahalanobis distance matrices further informed that pairs involving Zebu Bororo cattle had the higher differentiation of the dataset. However, contour plots constructed using eigenvalues computed via principal component analysis (PCA) illustrated a lack of differentiation among West African zebu cattle populations at the body measurements level. Correspondence analysis carried out on the 11 qualitative traits recorded allowed for ascertaining a clear differentiation between the Zebu Bororo and the other zebu cattle populations analysed which, in turn, did not show a clear differentiation at the qualitative type traits level. In our data, Zebu Bororo cattle had in high frequency qualitative features such as dropped ears, lyre-shaped horns and red-pied coat colour that are not frequently present in the other West African zebu populations analysed. A directional selection due to a rough consensus of the stock-keepers may be hypothesised. Performance of further analyses to assess the degree in which such breeding differences may be related to genetic or production differences are advised