Corporate Governance Practices and Regulatory Agencies on the Performance of Government Establishments in Sub-Saharan African

The study examines the effect of corporate governance practices and regulatory agencies on the performance of government establishments in Anambra State of Nigeria. Twenty five government establishments in Anambra State were studied using their general managers and Accountants as participants. Spearman’s rank correlation coefficient and student t-transformation were used to test for relationship and significant respectively. The results of this study reveal that corporate governance has positive and significant relationship on the performance of corporate governance regulatory agencies. Further results reveal that agreement on corporate governance has positive and significant relationship with lay down standard. The study calls for corporate governance regulatory agencies to discharge their duties without fear of favour and should shun all forms of gratification and render objective report on government organizations. This will redirect government establishment on improving their corporate governance practices, which will enhance their firm value and meet the need of the future generation. Keywords: Corporate Governance, Corporate Practices, Corporate Mechanism, Regulatory Agencies, Standar

Effect of chemical agents on morphology, tensile properties and water diffusion behaviour of hibiscus sabdariffa fibers

Effective utilization of Hibiscus sabdariffa fibers in composites applications as a reinforcing fibers in polymer matrix have been a major concern due to its poor mechanical and hydrophilic properties. It will be of benefits to environmental and technological advancement, if its properties are properly handled. In this study, the morphological, tensile and water absorption characteristics of H. sabdariffa fibers was aimed to be investigated. H. sabdariffa fibers was modified using sodium hydroxides, sodium lauryl sulphate and ethylene diamine tetraacetic acid. The morphology using scanning electron microscopy, tensile properties (strength, modulus, elongation and energy at break), water absorption and water diffusion behaviours were studied. Chemical modifications improved fiber surface and roughness, tensile strength and modulus, elongation and energy at break with reduced water absorption of H. sabdariffa fibers. The water diffusion behaviour is less - Fickian controlled by water penetration rate. Hence improved the hydrophobic nature of H. sabdariffa fibers. Keywords: Hibiscus sabdariffa fibers, tensile properties, morphology, water diffusion behaviou

Evaluation of pawpaw leaves extract as anti-corrosion agent for aluminium in hydrochloric acid medium

Pawpaw leaves extract was examined as anti-corrosion agent for aluminium in hydrochloric acid medium. The extract and corrosion product were analyzed using Fourier transform infrared spectrophotometer (FTIR). Thermometric, gravimetric, potentiodynamic polarization and scanning electron microscopic methods were employed in the study. The inhibition efficiency was optimized using Response Surface Methodology (RSM) of Design Expert Software 9. Inhibitor concentration (0.2 g/l – 1.0 g/l), temperature (303 K – 333 K) and time (1hour - 5 hours) were the considered factors. It was revealed that stretched C-H and O-H functional groups were predominantly responsible for the corrosion inhibition process. The adsorption of the extract on the aluminium surface adhered to the mechanism of physical adsorption. A quadratic model adequately described the inhibition process. Optimum inhibition efficiency of 80.58% was obtained at inhibitor concentration of 0.961 g/l, temperature of 311.459 K and time of 3.932 hrs. The extract is a mixed-type inhibitor that can control both cathodic and anodic corrosion.Keywords: Aluminium, Anti-Corrosion, HCl, Pawpaw Leaves

Tensile responses of treated Cissus populnea fibers

Improvement and effectiveness of polymers through reinforced materials coupled with environmental nuisance of the Cissus populnea fiber remains an area of concern. Tensile responses of chemically treated C. populnea fibers were investigated. Gravimetric analysis was used to determine the composition of C. populnea fibers. Sodium hydroxide (NaOH), acetic anhydride(AC) and ethylene diamine tetra-acetic acid (EDTA), respectively, were used for fiber treatment and optimi zed with variable parameters (concentration and time) using response surface methodology (RSM) with central composite design. Scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) were studied. At optimum treatment conditions, NaOH, AC and EDTA, respectively, increased the tensile strength of C. populnea fiber by 33.49, 274 and 194.52% as well as tensile modulus by 793.43, 20799.43 and 855%. Hence acetic anhydride treatment gave the best tensile properties of C. populnea fibers as cor roborated by SEM with EDS. Thus, the effective use of C. populnea fiber in composite applications can be improved by chemical surface modifications. Keywords: Cissus populnea fiber; RSM; tensile properties; SEM; EDS

Optimization and electrochemical study on the control of mild steel corrosion in hydrochloric acid solution with bitter kola leaf extract as inhibitor

Response surface methodology was applied to predict the optimum control of mild steel corrosion in acid medium with bitter kola leaf extract as inhibitor. The experiment was carried out to investigate the mutual interactions between the considered independent variables and the expected responses. Thermometric, gravimetric, potentiodynamics polarization and electrochemical impedance spectroscopy were used in the corrosion inhibition study. As a supplementary technique, infrared spectroscopy was used to analyze the pure extract and corrosion products and it was observed that some peaks shifted while some disappeared. Inhibition efficiencies of 88.24 %, 86.81 %, 90 %, 89.5 % and 85.3 % were obtained from optimization, thermometric, gravimetric, potentiodynamics polarization and electrochemical impedance spectroscopic techniques, respectively. The bitter kola leaf extract behaved as a mixed-mode inhibitor. Application of response surface methodology in this study was found to be good in predicting the optimum range for controlling of metal corrosion thereby reducing the number of experimental runs.Keywords: Acid, bitter kola leaf, Fourier transform infrared, mild steel, electrochemical impedance spectroscopy, potentio dynamics polarizatio

Optimization of Zinc Recovery from Sphalerite Using Response Surface Methodology and Particle Swarm Optimization

Hydrometallurgical leaching process has been identified as a viable procedure for recovering metals of value from their matrices. The optimization of zinc recovery from sphalerite in nitric acid solution was carried out in this study. The Central Composite Rotatable Design (CCRD) of Response Surface Methodology (RSM) and Particle Swarm Optimization (PSO) tool in matlab were deployed for the optimization studies. RSM modeling gave optimum conditions of 73.0 °C leaching temperature, 3.48 M acid concentration, 0.027 g/mL solid/liquid ratio, 411.02 rpm stirring rate, and 82.82 minutes leaching time; with a zinc yield of 87.67 %. With PSO, about 86.9 % zinc was recovered at a leaching temperature of 69.1 °C, acid concentration of 1.8 M, solid/liquid ratio of 0.031 g/mL, stirring rate of 270 rpm and leaching time of 85 minutes. Thus, PSO and RSM proved to be good optimization tools

Effect of Chemically Modified Cissus Populnea Fibers on Mechanical, Microstructural and Physical Properties of Cissus populnea/High Density Polyethylene Composites

The effect of chemically modified Cissus populnea (C. populnea) fiber using sodium hydroxide (NaOH) and sodium lauryl sulphate (SLS) on mechanical, morphological and physical (density and water absorption behaviour) properties of C. populnea fiber/recycled HDPE composites was aimed to be investigated. The composites of unmodified and modified C. populnea fiber/HDPE were prepared using injection molding machine. The mechanical properties (tensile strength and modulus, flexural strength and modulus, hardness and impact strength), interfacial shear stress, density, water absorption behaviour, scanning electron microscope (SEM) and Fourier transform infrared (FTIR) spectroscope were studied. The results shows that C. populnea fiber improved the mechanical properties of HDPE matrix with reduced impact strength of the composites. The NaOH and SLS treatments, respectively, improved the mechanical properties of C. populnea fiber/HDPE composites, although NaOH treated C. populnea fiber reduced the tensile modulus. The change in morphology and functional group, respectively, due to the modification was observed in SEM and FTIR. The density and water absorption of the composites, respectively, reduced when SLS modified C. populnea fiber was used compared to untreated C. populnea fiber/HDPE composites. The SLS treated C. populnea fiber prove to be superior for reinforcement, stiffness and light weight material.The effect of chemically modified Cissus populnea (C. populnea) fiber using sodium hydroxide (NaOH) and sodium lauryl sulphate (SLS) on mechanical, morphological and physical (density and water absorption behaviour) properties of C. populnea fiber/recycled HDPE composites was aimed to be investigated. The composites of unmodified and modified C. populnea fiber/HDPE were prepared using injection molding machine. The mechanical properties (tensile strength and modulus, flexural strength and modulus, hardness and impact strength), interfacial shear stress, density, water absorption behaviour, scanning electron microscope (SEM) and Fourier transform infrared (FTIR) spectroscope were studied. The results shows that C. populnea fiber improved the mechanical properties of HDPE matrix with reduced impact strength of the composites. The NaOH and SLS treatments, respectively, improved the mechanical properties of C. populnea fiber/HDPE composites, although NaOH treated C. populnea fiber reduced the tensile modulus. The change in morphology and functional group, respectively, due to the modification was observed in SEM and FTIR. The density and water absorption of the composites, respectively, reduced when SLS modified C. populnea fiber was used compared to untreated C. populnea fiber/HDPE composites. The SLS treated C. populnea fiber prove to be superior for reinforcement, stiffness and light weight material

Optimization of coagulation-flocculation process for colour removal from Azo dye using natural polymers: response surface methodological approach

The ability of organic polymer rich coagulants for colour removal from acid dye was studied. An improved method for the extraction of the active coagulant agent from the seeds was employed. The effects of four variables including pH, coagulant dosage, dye concentration and time were analyzed. Response surface methodology (RSM) using face-centered central composite design (FCCD) was used to optimize the four variables. Increase in the colour removal efficiency was higher in acidic solution pH. Accurate control of coagulant dosages gave optimum destabilization of charged particles and re-stabilization occurred at above 800mg/L dosages. Polymer performances were measured through time-dependent decrease in particle concentrations following aggregates growth. The verification experiment agreed with the predicted values having less than 4% standard error. Overlay contour plot was used to establish an optimum condition for the multiple responses studied. The response surface approach was appropriate for optimizing the coagulation-flocculation process while minimizing the number of experiments. Coagulants studied should be considered as an alternative for conventional coagulants that are widely used in dye wastewater treatment plants.Keywords: Coagulation-flocculation, Azocarmine G, multiple response optimization, response surface design, colour removal, natural organic polymers

Optimum prediction for inhibition efficiency of Sapium ellipticum leaf extract as corrosion inhibitor of aluminum alloy (AA3003) in hydrochloric acid solution using electrochemical impedance spectroscopy and response surface methodology

Statistical optimization was used to optimize corrosion inhibition efficiency of Sapium ellipticum leaf extract as corrosion inhibitor of aluminum in acid medium. Response surface methodology was applied, and the effects of four independent variables; acid concentration, inhibitor concentration, temperature, time, and their expected responses were determined. Central composite design a statistical tool was used to generate a total of 16 individual experimental runs, which was previously design to study the effects of these variables during corrosion process. The uniqueness of the model was scrutinized with various criteria including coefficient of determination (R2 = 0.987), p value (< 0.0001), adequate precision (30.22) and coefficient of variation (5.30). The RSM is well fitted in the model which adequately predicted the optimum inhibition efficiency of 96.73% at optimum inhibitor concentration of 1.5g/L-1, acid concentration 1 M, temperature of 303 K and time of 6 hours. Also the electrochemical concept signifies that Sapium ellipticum acts as a mixed-kind inhibitor. The experimental data obtained is in conformity with other research works.   Bull. Chem. Soc. Ethiop. 2020, 34(1), 175-191. DOI: https://dx.doi.org/10.4314/bcse.v34i1.1

Evaluation of bio-coagulants for colour removal from dye synthetic wastewater: characterization, adsorption kinetics, and modelling approach

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