Thermal Radiation Effect on Fully Developed Natural Convection Flow in a Vertical Micro-Channel

The effect of thermal radiation on steady fully developed natural convection flow in a vertical micro-channel is presented in this article. Effects of velocity slip and temperature jump conditions are taken into account due to their counter effects on both the volume flow rate and the rate of heat transfer. Due to the presence of thermal radiation, the momentum and energy equations are coupled system of ordinary differential equations. Governing coupled nonlinear equations are solved analytically by employing the perturbation analysis method to obtain an expression for fluid temperature, fluid velocity, rate of heat transfer and skin friction on the microchannel walls. The effect of various parameters controlling the physical situation such as thermal radiation, temperature difference, Knudsen number, and fluid wall interaction are discussed with the aid of line graphs and Tables. Results indicate that both velocity and temperature enhanced with the increase of the thermal radiation parameter. Keywords: Thermal radiation, Natural convection, Micro-channel, Velocity slip, Temperature jump

Factors Determining Birth Intervals: A Multilevel Mixed Effect Parametric Survival Approach

Interval between births plays an important role in maternal health as well as child health. This study applies the methodology of Flexible parametric survival models to data on successive births among Nigeria women using the dataset from 2018 National Demographic Health survey. The flexible parametric survival model with Weibull baseline distribution was found to be the best among other fitted baseline distributions. The factors, zone of residence, educational qualification, religion, economic status and age at first birth were found to be significant in predicting the birth intervals. It was found that random effect parameter indicates that the interval between successive births is similar from the same woman. Keywords: Birth intervals, Baseline hazard, Mixed effect, Flexible parametric model, AIC.

Detection of Bacteriological Contaminants in Hand-Pump Fitted Borehole Water from a Residential Suburb in Ringim Local Government, Jigawa State

Water from borehole source can be contaminated due to indiscriminate waste disposal. This pilot study was conducted to assess the bacteriological quality of water from five (5) hand-pump-fitted borehole sources present in Sabon Gari quarters in Ringim Local Government Area of Jigawa State. Presumptive, confirmed and completed tests were employed to determine total and faecal coliforms from the water samples using most probable number (MPN) technique. Bacterial isolates were identified by standard microbiologicalmethods. Results obtained indicate that all the water samples across all the dilution strengths tested recorded substantial growth of total coliforms at 37.3°C while faecal coliforms were observed at 44°C after incubation for 48 h. Using the MPN table, the five water samples assayed recorded 50 MPN/100mL, 14 MPN/100mL, 3 MPN/100mL, 5 MPN/100mL and 1 MPN/100mL. Results were also positive for gas and acid production in all samples collected characteristic of presence of E. coli. The results obtained in this study show bacterial contamination of the water from the boreholes which may constitute a public health risk. It is therefore recommended that the water pumped from these boreholes should be subjected to adequate treatment to meet World Health Organization (WHO) required standard for potable water meant for drinking. Keywords: Boreholes, hand pump, most probable number, total coliforms and faecal coliforms.

Application of Morphostructural and Spatial Analyses in Placer-Gold Source Interpretation within Wonaka Schist Belt, Northwestern-Nigeria

Morphologic and placer features were used to characterize, determine the provenance, and transport distances of gold grains within the River Gagare drainage basin of the Wonaka Schist Belt. Field studies, scanning electron examination coupled with energy dispersive spectrometry and binocular microscopy were utilized to study the spatial distributions, shape, size, inclusions, primary and fluvial transport-induced deformations, as well as Cailleux flatness indices. The grains are dominantly subrounded (71%), with the length between 35 – 800 µm and width of 10 – 778 µm while the rounded grains have a mean length of 292.5 µm and width of 179 µm. Similar values for circularity and sphericity are observed in the sub-rounded grains, with slight variations of 2.7 circularity and 2.6 sphericitydistinguished in the rounded grain subset. The Cailleux flatness index range from 2.5 to 9 for subrounded grains and 2 – 15.5 for the rounded, indicating the multisource nature of the grains. The grains are consistent with short to moderate transport distances from the lode sources. The similarities in physical features, lack of delicate secondary growth structures and irregular grain outlines point to a detrital source for the placer deposits. Evidence of emulsion crystallisation type is indicated by the presence of sub- to anhedral inclusions within the Au grains. Keywords: Placer gold, Cailleux flatness indices, Wonaka Schist Belt, Provenance, Northwest Nigeria

Farmers’ Adoption of System of Rice Intensification in Chanchaga Local Government Area of Niger State, Nigeria

The study evaluated the adoption of System of rice intensification (SRI) among rice farmers in Chanchaga Local Government Area of Niger State, Nigeria. A 3-stage sampling technique was used to collect data for the study through a structured questionnaire and interview schedule administered to 200 rice farmers. The results indicated that the majority of the farmers were males (83.0%) and married (68.5%) with no formal education (50.5%). Mean age was 44.1 years, household size was 8.8 persons, farming experience of 16years, average monthly income was N590,000.00 and average farm size was 1.7 ha. The most adopted SRI production practice was fertilizer and herbicide application (100.0%), planting depth (91.5%) manual land cultivation and planting method (91.0%). The respondents were at different stages of adoption with accelerating growth, rotary weeding and use of organic fertilizer having positive adoption index of 0.972, 0.970 and 0.601, respectively. Level of adoption of SRI technologies was low (34.5%) with a positive perception. Major constraints to SRI technologies were high labor ( =3.27), non-awareness of SRI technologies ( =3.14) inadequate understanding of SRI ( =2.89). The profitability of SRI in rice cultivation was higher compared to the conventional method. Therefore, the provision of more training and demonstration programmes and input subsidy should be encouraged to boost adoption of SRI for improved rice production. Keywords: Rice Intensification, Farming activities, Training, Chanchaga, System, Niger State

Bacterial Contamination Associated with Mobile Cell Phones among Undergraduate Students of Federal University of Lafia, Nasarawa State, Nigeria

Mobile cell phones are extensively used globally. This study was aimed at determining bacterial contamination associated with mobile cell phones among undergraduate students of Federal University of Lafia, Nasarawa State, Nigeria. One hundred swab samples from mobile cell phones were randomly collected from the students’ cell phones between August 2019 and December 2019. Demographic factors like age, gender, mobile phone type, storing of mobile cell phones, cleaning habits and use in toilets were collected using a semi-structured questionnaire. The samples were analysed using standard microbiological techniques. The data collected were analysed using percentile and SPSS version 20.0. The value (p<0.01) was statistically considered to have significant associations. Microbial analysis showed that 70 nondisinfected samples were contaminated by eight diverse types of bacteria, which included Escherichia sp., Salmonella sp., Bacillus sp., Pseudomonas sp., Staphylococcus sp., Klebsiella sp., Micrococcus sp and Enterobacter sp. The swabbed cell phones of females (56.3%) were more contaminated than those of males (43.7%) with bacterial load count of 41.9 x 103 and 28.8 x 103 CFU/mL among females and males, respectively. The mobile cell phones used in toilets (75.0%) were highly contaminated by bacteria. Users who did not cut their nails had higher contamination (69.4%) than those users who cut their nails (34.3; p = 0.01). The age of mobile cell phones within 6 – 12 months had 55.5% for females and 23.5% for males. This study showed that mobile cell phones harbor bacteria liable for causing health threats to handlers. Therefore, awareness programs concerning hand hygiene and discouraging their use in toilets to avoid causing severe health consequences. The use of disinfectants to wipe mobile cell phones whenever contamination is encountered is advocated to safeguard public health. Keywords: Mobile Cell Phone, Swabs, Microbes, Contamination

In Silico Screening of Sesquiterpene Lactones as Aldose Reductase Inhibitors

Aldose reductase, a key enzyme of the polyol pathway catalyses NADPH-dependent reduction of glucose to sorbitol. Increased activity of this enzyme is considered a major factor contributing to the development of diabetic complications hence could be an important target in the treatment of these complications. In this work, a database of sesquiterpenes was prepared and screened for their drug-like properties based on the Lipinski’s rule of 5. The co-crystallised structure of aldose reductase was obtained from the Protein Databank and prepared for docking. In silico docking experiments was performed on Autodock tools using 198 sesquiterpene lactones that passed screening, and compounds with the lowest binding energy and favourable binding interactions were selected for molecular docking simulation. Six of the best ranking compounds selected had binding energies ranging from–11.96 Kcal/mol to -9.45 Kcal/mol and were comparable to the energy of the standard inhibitor Idd594 used in the study. They also show good complementarity in their binding to the residues of the binding pocket. The results suggest that dehydrooopodin (1), 11(S),13-dihydrolactucopicrin (2), and Chrysanin (3) offered potential inhibitory activities toward aldose reductase and may serve as lead compounds for in vivo validation as aldose reductase inhibitors. Keywords: Sesquiterpene lactones, Aldose reductase, Binding energy, Molecular docking, Autodock

Marketing Expansion Strategies for Local Crops-Based Couscous in Tahoua State, Niger Republic

This study investigates the own-price and cross-price elasticities for locally grown crops-based couscous and compares confidence intervals computation for willingness-to-pay and market shares under Krinsky Robb and Delta bootstrapping methods. Syntheses of previous literature and a focus group with consumers had helped to identify nine brands of couscous included in this research. The fractional factorial design was used to collect data from three hundred consumers, while the multinomial logit was used to analyze data. Results indicate that rice, cowpea and millet-based couscous were the most preferred by consumers and their market share accounts of more than fifty percent. The Results from simulation showed that confidence intervals under Krinsky and Robb stabilize as a sample size increases and thereby adjusting for skewness. However, confidence intervals under Delta computation are constant regardless of sample size, thereby failing to adjust for skewness. Finally, results also indicate that skewness was also accommodated in confidence intervals for market share because its values progressively adjust as sample size increases. These findings may be useful to boost cropbased couscous demand in the study area and beyond and thereby improving farmers’ revenue and offering diet diversification opportunity. Keywords: Marketing expansion, Strategies, Local crops, Couscous, Willingness-to-pay

Nonlinear Kinetic and Equilibrium Adsorption Isotherm Study of Cadmium (II) Sorption by Dacryodes edulis Biomass

The kinetics and equilibrium adsorption isotherm of cadmium (II) adsorption onto Dacryodes edulis (native peer seed) biomass was studied using a nonlinear approach, which is unpopular but proven in some literature to be more reliable and easier. In optimizing the process, about 98% removal of the cadmium ion was achieved within five minutes at pH 7 by contacting just 30 mg of the Dacryodes edulis seed biomass with the adsorbate solution of a concentration of 100 mg/L. Non-linear investigation of the kinetics and adsorption isotherms of the process was done using the R console statistical and computing software. The results indicated that the Elovich mechanism and the Freundlich adsorption isotherm most suitably described the kinetics and adsorption isotherm, respectively, of the process as provided by their least values of the sum of squared residuals (SSR). This outcome implied a chemical adsorption (chemisorption) mechanism and a multi-layer coverage by the cadmium ions on heterogeneous active sites of the biomass surface with a Freundlich constant or capacity factor, Kf of 27.83 mg g-1, heterogeneity factor, 1/n of 0.2614 and Elovich constants, α and β of 7.0 mg g−1 s−1 and 1.0 g mg-1, respectively. These findings indicate that Dacryodes edulis seed biomass has a good potential for cadmium (II) adsorption. Keywords: Dacryodes edulis, Elovich kinetic model, Freundlich isotherm, Langmuir isotherm, Nonlinear

Split-plot Central Composite Experimental Design Method for Optimization of Cake Height to Achieve desired Texture

In many industrial experimental situations, the levels of certain factors under investigation are much harder to change than others due to time and/or cost constraints. An appropriate approach to such situations is to restrict the randomization of the hard-to-change (HTC) factors, which leads to a split-plot structure. This work designs and conducts a split-plot central composite experiment for optimizing cake height using oven temperature(Factor A) as the HTC factor, amount of flour (B), baking powder (C), and amount of milk (D) as the easy-to-change (ETC) factors. A second-order split-plot central composite design (CCD) model was fit to the generated data and analyzed using generalized least squares (GLS). A stationary point, which gives optimum cake height, was then determined. The results show that main effects of oven temperature, flour, baking powder, and milk were highly significant on the cake height . Their quadratic effects were also significant except that of the flour. The flower/baking powder interaction effect was significant. The fitted model accounted for about 95% of the total variability in the cake height data. The observed optimum cake height was ̂ at a stationary point: A . This study has established the potentials of response surface experiments in optimizing products in food industries. Keywords: Experiment, split-plot CCD, Cake height, Design, Stationary point.