Study of the Inhibitive and Adsorptive Properties of Mild Steel in H2SO4 - Boscia senegalensis Plant Environment

The inhibitive and adsorption properties of ethanol extract of Boscia senegalensis for the corrosion of mild steel in H2SO4 were investigated using weight loss, linear polarization, and scanning electron microscopy techniques. From the result, it was found that the corrosion rate of mild steel to decrease with an increase in the concentration of the inhibitor as well as increase with an increase in temperature of the environment. The inhibition efficiency of the inhibitor increases with increasing concentration but decreases with increasing temperature. The inhibition potential of ethanol extract of Boscia senegalensis is attributed to the presence of saponnin, tannin, phlobatanins, anthraquinone, cardiac glycosides, flavanoid, terpene, and alkaloid in the extract. The adsorption of the inhibitor on mild steel surface was found to be exothermic, spontaneous and is best described by Freundlich and Temkim adsorption model. The calculated values of activation energy, enthalpy of activation, entropy of activation, free energy of adsorption and the trend in the variation of inhibition efficiency with temperature, the mechanism of adsorption of the inhibitor by physical adsorption. Ethanol extract of Boscia senegalensis is a good adsorption inhibitor for the corrosion of mild steel in H2SO4. Tafel polarization analyses indicated that studied plant extract is a mixed type inhibitor. Keywords: boscia senegalensis; polarization; adsorption.

Foreign Trade-Foreign Exchange Nexus in Nigeria: a Vector Error Correction Modelling Approach

This study investigates trade foreign exchange nexus in Nigeria. This study is also done with a view to detecting the kind of relationship that exists between the two and also to investigate their co-integration. Annual time series data for the period 1996 – 2010 was used for the study. The Vector Correction Model (VECM) approach was employed to determine both the short and long run relationships. Results showed that the series becomes stationary after second difference. The co – integration test reveals five co – integrating vectors in the model, implying that the variables have the same stochastic drift. The study concludes that a long-term relationship exists between foreign trade and exchange rates implying that foreign trade flows have a strong link with exchange rates in Nigeria

Vibration under variable magnitude moving distributed masses of non-uniform Bernoulli-Euler beam resting on Pasternak elastic foundation

The dynamic response to variable magnitude moving distributed masses of simply supported non-uniform Bernoulli-Euler beam resting on Pasternak elastic foundation is investigated in this paper. The problem is governed by fourth-order partial differential equation with variable and singular coefficients. The main objective of this work is to obtain closed form solution to this class of dynamical problem. In order to obtain the solution, a technique based on the method of Galerkin with the series representation of Heaviside function is first used to reduce the equation to second order ordinary differential equations with variable coefficients. Thereafter the transformed equations are simplified using (i) The Laplace transformation technique in conjunction with convolution theory to obtain the solution for moving force problem and (ii) finite element analysis in conjunction with Newmark method to solve the analytically unsolvable moving mass problem because of the harmonic nature of the moving load. The finite element method is first used to solve the moving force problem and the solution is compared with the analytical solution of the moving force problem in order to validate the accuracy of the finite element method in solving the analytically unsolvable moving mass problem. The numerical solution using the finite element method is shown to compare favorably with the analytical solution of the moving force problem. The displacement response for moving distributed force and moving distributed mass models for the dynamical problem are calculated for various time t and presented in plotted curves

Food Expenditure Patterns Among Urban Households In Ibadan Southwest Local Government Area, Oyo State

This study examines food expenditure patterns among urban households in Ibadan South West Local Government Area of Oyo State. The primary data used for the study were obtained through structured questionnaire using random sampling technique. Descriptive statistics and least square regression model were used to analyse the data collected from respondents. Descriptive analysis showed that 82.5% of the household heads were males, 65% of them were married, and 55% fell within the age bracket of 30 and 39 years, while 65% were salary-earners. Most of the respondents (79.2%) had tertiary education and the average household size was found to be 5. Furthermore, 49.2% bought foodstuffs from the market for home consumption on a monthly basis and 52.5% spent less than N10, 000 monthly on food.  The result of the least square regression model showed that the age of respondents, level of education and occupation (salary-earner or self-employed) of the household head, as well as the household income were significantly influenced by household’s monthly food expenditure in the study area. The study recommends among other things enlightenment programmes that will    educate the urban dwellers on the  need to eat good quality and hygienic food.   &nbsp

Comparative analysis of economic growth in Nigeria and Kenya: A fractional integration approach

This paper is a comparative analysis of Nigeria and Kenya, the largest economies in West and East Africa respectively, on the basis of the time series properties of their economic activities through the Gross Domestic Product (GDP) and growth rate series. It further analyses how differing policy and political economy processes contributed to the two countries' economic growth trajectories despite becoming independent republics at almost the same time. We study the two economies using a long‐memory‐fractionally integrated approach. The results show a high degree of persistence in both cases. When non‐linearities are taken into account, evidence of mean reversion is found in the GDP series in the two countries. This is indicative of how the two countries in very distinct African contexts followed broadly different but, in some ways, similar paths toward economic growth since independence.pre-print277 K

Theoretical and Experimental Inhibitive Properties of Mild Steel in HCl by Ethanolic Extract of Boscia senegalensis

The experimental aspect of the corrosion inhibition potentials of Boscia senegalensis was carried out using gravimetric and linear polarization techniques techniques as well as scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR), whereas the theoretical aspect was done by using the Density functional theory (DFT) calculations to performed and model the electronic structures of some extract constituents, including Physiosorptive interactions with the Fe surface. The analyses of the experimental results showed that the inhibition efficiency increased with increase in concentration of the inhibitor and decreased with increase in temperature. The efficiency of the extract in HCl (70%).  Thermodynamic parameters revealed that the adsorption of extract onto the metal surface was spontaneous, exothermic and supported the Physical adsorption process. FTIR results showed that the inhibition mechanism was by absorption process, through the functional groups present in the extract and that of the inhibited. Surface morphology also revealed that corrosion product confirmed the protection offered by the extract on the surface of the metal immersed in the acid media. The data obtained were fitted into various adsorption isotherms though the Freundlich isotherm was found to be best fit. Keywords: Inhibition, density functional theory, corrosion, boscia senegalensis

Developing affordable and accessible pro‐angiogenic wound dressings; incorporation of 2 deoxy D‐ribose (2dDR) into cotton fibres and wax‐coated cotton fibres

The absorption capacity of cotton dressings is a critical factor in their widespread use where they help absorb wound exudate. Cotton wax dressings, in contrast, are used for wounds where care is taken to avoid adhesion of dressings to sensitive wounds such as burn injuries. Accordingly, we explored the loading of 2‐deoxy‐D‐ribose (2dDR), a small sugar, which stimulates angiogenesis and wound healing in normal and diabetic rats, into both types of dressings and measured the release of it over several days. The results showed that approximately 90% of 2dDR was released between 3 and 5 days when loaded into cotton dressings. For wax‐coated cotton dressings, several methods of loading of 2dDR were explored. A strategy similar to the commercial wax coating methodology was found the best protocol which provided a sustained release over 5 days. Cytotoxicity analysis of 2dDR loaded cotton dressing showed that the dressing stimulated metabolic activity of fibroblasts over 7 days confirming the non‐toxic nature of this sugar‐loaded dressings. The results of the chick chorioallantoic membrane (CAM) assay demonstrated a strong angiogenic response to both 2dDR loaded cotton dressing and to 2dDR loaded cotton wax dressings. Both dressings were found to increase the number of newly formed blood vessels significantly when observed macroscopically and histologically. We conclude this study offers a simple approach to developing affordable wound dressings as both have the potential to be evaluated as pro‐active dressings to stimulate wound healing in wounds where management of exudate or prevention of adherence to the wounds are clinical requirements