A.E. Okoronkwo, S.J. Olusegun and O.O. Oluwasina
The purpose of this investigation was to study the inhibitive action and adsorption potential of chitosan extracted from Archachatina marginata snail shells on the corrosion of…
Abstract
Purpose
The purpose of this investigation was to study the inhibitive action and adsorption potential of chitosan extracted from Archachatina marginata snail shells on the corrosion of plain carbon (mild) steel in acid media.
Design/methodology/approach
Weight loss and thermometric methods were used during this investigation. Characterization of the obtained chitosan was accomplished with Fourier transform infrared spectroscopy analysis. The effects of parameters influencing the inhibition process (concentration and temperature) were evaluated, and the sorption isotherms and thermodynamic parameters were derived.
Findings
The results obtained showed that chitosan has good inhibition potential with an efficiency of 93.2 per cent. The inhibition efficiency decreased with an increase in temperature but increased with increasing concentration of chitosan. Test results best fitted the Langmuir Isotherm with a correlation coefficient (R2) of 0.999. The thermodynamic parameters studied reveal that the adsorption of chitosan on the surface of mild steel is spontaneous.
Originality/value
The paper fulfills an identified need in finding solutions to the problems of metal corrosion using agricultural wastes.
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Khalid Rashid and Anees Khadom
The purpose of this study is to investigate the corrosion inhibition of mild steel alloy in 2 M H3PO4 solution by the pomegranate peel extract as a friendly inhibitor was studied…
Abstract
Purpose
The purpose of this study is to investigate the corrosion inhibition of mild steel alloy in 2 M H3PO4 solution by the pomegranate peel extract as a friendly inhibitor was studied at various temperatures, inhibitor concentrations and immersion times.
Design/methodology/approach
A weight loss method was used to evaluate the corrosion rate. The experimental Taguchi design method was used for the distribution of experiments. The experimental design gave results which were impossible to show graphically. However, this problem was solved effectively with the aid of regression analysis.
Findings
Corrosion rate increased with temperature according to Arrhenius equation. It was found that the efficiency of inhibition was increased with an increase in the concentration of inhibitor and immersion time. However, this diminishes with increased temperature. According to Langmuir isotherm, the inhibitor was adsorbed physically on steel surface. The negative sign of estimated heat of adsorption suggests a stable spontaneous inhibition process. Combination of mathematical and statistical analysis was proposed to demonstrate the results of corrosion rate with high correlation coefficients. In addition, Fourier transform infrared spectrometer examinations confirmed that the organic inhibitor consists of phenolic components as main materials.
Originality/value
Using unconventional approach for evaluation of environmentally friendly inhibitor for corrosion of mild steel in phosphoric acid solution.
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S.A. Umoren, Z.M. Gasem and I.B. Obot
The purpose of the paper was to investigate the use of aqueous extract of date palm (Phoenix dactylifera) leaf as a green inhibitor for corrosion of carbon steel in 1M…
Abstract
Purpose
The purpose of the paper was to investigate the use of aqueous extract of date palm (Phoenix dactylifera) leaf as a green inhibitor for corrosion of carbon steel in 1M hydrochloric acid (HCl) solution.
Design/methodology/approach
Extracts from the date palm were used as the main component of an environmentally friendly corrosion inhibitor for use in HCl pickling processes. Inhibition behavior on carbon steel in HCl was investigated using weight loss measurements, linear and potentiodynamic polarization curves, electrochemical impedance spectroscopy and scanning electron microscopy.
Findings
The results show that the extract exhibited good inhibition performance in 1M HCl. The inhibition efficiency increased with increase in the concentration of the inhibitor but decreased with increase in temperature. Inhibition efficiency also was found to increase as immersion time increased. The inhibitive action was due to adsorption of the date palm leaf components on the steel, which was consistent with the Langmuir isotherm.
Practical implications
Date palm leaf extract (DPLE) is an effective inhibitor at room temperature and can be used to protect plain carbon steel from corrosion in HCl solution.
Originality/value
This study provides new information on the inhibiting characteristics of DPLE under specified conditions. The environmentally friendly inhibitor could find possible applications in metal surface anodizing and acid pickling processes.
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Athira Krishnan and S.M.A. Shibli
This paper aims to evaluate the inhibitive action of different concentrations of Sesbania grandiflora leaf extract on the mild steel corrosion in an aggressive HCl medium under…
Abstract
Purpose
This paper aims to evaluate the inhibitive action of different concentrations of Sesbania grandiflora leaf extract on the mild steel corrosion in an aggressive HCl medium under different experimental conditions.
Design/methodology/approach
Weight loss investigation, open-circuit voltage analysis, Tafel polarisation, AC impedance analysis, etc. were used for the evaluation of inhibition efficiency. The influence of immersion period on inhibition efficiency was evaluated. The mechanism of action of the inhibitor is also discussed. Infrared (IR) spectroscopy and energy-dispersive X-ray spectroscopy analysis were used to characterise the passive film.
Findings
The results suggested that 10,000 ppm solution has maximum inhibition efficiency of 98.01 per cent at room temperature, while 1,000 ppm solution also exhibited a better efficiency of about 96.16 per cent. Efficiency of inhibitor solution was found to increase with an increase in its concentration. Polarisation study proposed the solution as an anodic inhibitor. Impedance study confirmed the formation of a protective layer over the surface of the specimen, and the constituents of the film were identified using IR spectroscopy. Stability of the film adsorbed on the steel was cleared from the steady open-circuit potential value. Study on action of the inhibitor under accelerated conditions revealed the fact that the efficiency of extract in preventing corrosion is good under stimulated conditions also.
Practical implications
The action of inhibitor sustains for a sufficient time period and could sustain under stimulated conditions. Hence, its application is practically possible in industries. The proposed inhibitor is widely available and is environmentally safe.
Originality/value
HCl is an industrially important chemical used for acid cleaning, acid pickling, etc. HCl was used as an aggressive corrosion environment. As the chances for mild steel to be in contact with HCl were very high, it was important to develop an efficient, economical and eco-friendly inhibitor for corrosion.
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Asmae Bouoidina, Mehdi Chaouch, Abdelfattah Abdellaoui, Amal Lahkimi, Belkheir Hammouti, Fadoua El-Hajjaji, Mustapha Taleb and Ayssar Nahle
The inhibition effect of Foeniculum vulgare seeds’ (FVS) extract on the corrosion of mild steel in acidic medium was studied using weight loss, electrochemical impedance…
Abstract
Purpose
The inhibition effect of Foeniculum vulgare seeds’ (FVS) extract on the corrosion of mild steel in acidic medium was studied using weight loss, electrochemical impedance spectroscopy and Tafel polarization, as well as the surface morphology of the mild steel.
Design/methodology/approach
Weight loss measurements, potentiodynamic tests, electrochemical impedance spectroscopy studies and gas chromatography/mass spectrometry and scanning electron microscopy analysis of FVS extract were performed.
Findings
FVS extract acts as a good inhibitor for the corrosion of mild steel in 1.0 M HCl. The inhibition efficiency increases with the increase in inhibitor concentration but decreases with the increase of temperature.
Practical implications
FVS extract was observed to play an important role in the corrosion inhibition of mild steel in acidic solution.
Originality/value
This paper is intended to be added to the family of green inhibitors which are highly efficient inhibitors and can be used in the area of corrosion prevention and control.
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Santiago Flores Merino, Juan José Caprari, Luis Vasquez Torres, Luis Figueroa Ramos and Antonella Hadzich Girola
The purpose of this paper is to study the ability of commercial tara powder to convert rust into iron tannate and evaluate their use as raw material for the formulation of water…
Abstract
Purpose
The purpose of this paper is to study the ability of commercial tara powder to convert rust into iron tannate and evaluate their use as raw material for the formulation of water based rust converter.
Design/methodology/approach
Water-borne acrylic primers were formulated with tara powder and aqueous tara extract and applied on steel rusted by three different methods. The conversion of rusted steel by tara tannins was studied by X-ray diffraction spectroscopy, infrared spectroscopy and scanning electron microscopy. The acrylic primers, containing hydrolysable tannins, were coated with alkyd finish and were evaluated in comparison to commercial systems in accelerated corrosion tests. The corrosion inhibition effects of tara powder on mild steel in 0.1M NaCl were studied by DC electrochemical techniques.
Findings
Tara tannin converts rust to ferric tannate and increases the magnetite content of rusted steel. The water-based acrylic primer formulated with aqueous extract of tara, alkyd-coated finish, showed performance equivalent to pure alkyd system.
Research limitations/implications
The chlorides content in the commercial tara powder can be screened the beneficial effect of hydrolysable tannins to convert rust. Furthermore, the water-based rust converter formulated with acrylic resin may be sensitive to salt contamination of rust.
Originality/value
Hydrolysable tannins from commercial tara powder have not been studied yet in its application to the development of rust converters. A water-based primer formulated with commercial tara powder developed for the effective treatment of rusted surfaces can be of interest as an environmentally friendly to current commercial approaches.
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Busayo Bidemi Adeyemi, Victor Olusegun Okoruwa and Adesola Ikudaisi
The purpose of this paper is to assess the efficiency of rice millers and determine factors influencing cost efficiency in Southwest Nigeria using the cost route approach.
Abstract
Purpose
The purpose of this paper is to assess the efficiency of rice millers and determine factors influencing cost efficiency in Southwest Nigeria using the cost route approach.
Design/methodology/approach
The paper analyses cost efficiency of rice millers using primary data collected from 62 respondents through a structured questionnaire. A multi-stage sampling procedure was employed for this purpose. The profile of rice millers and mills were derived using the descriptive analysis. Cost efficiency of the millers was obtained using the quadratic cost function analysis, and Tobit regression was used to determine factors that influence cost efficiency.
Findings
The results showed that cost efficiency indexes range from 1 to 57 percent averaging at 20.2 percent. Large rice mills were found to be most efficient with the mean cost efficiency of 25 percent. Paddy, transport and energy costs contributed positively and significantly (p=0.05 and p=0.01) to cost efficiency. Milling capacity and machine age increase cost efficiency while the distance to purchase paddy and quantity of diesel used reduces cost efficiency.
Social implications
The paper shows that there is enough potential for rice millers to improve their cost efficiency based on the available technology. This has a direct implication on the economy through the increased domestic production and processing of rice to meet the increasing demand for locally produced rice.
Originality/value
The paper attempts to bridge the gap in the literature of cost efficiency among rice millers in Nigeria, and specifically in the application of the normalized quadratic cost function in estimating cost efficiency in the rice milling sector in Nigeria.
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Olusegun Felix Ayadi and Oluseun A. Paseda
The study aims to examine the appropriateness of the coefficient of elasticity of trading (CET) as a measure of liquidity using Nigerian stock market data. Given that liquidity is…
Abstract
Purpose
The study aims to examine the appropriateness of the coefficient of elasticity of trading (CET) as a measure of liquidity using Nigerian stock market data. Given that liquidity is multidimensional, the CET is complemented with the popular measure of liquidity, turnover ratio to explore the causal relationship among the CET, turnover ratio and market return to determine their relevance in security valuation. In other words, an attempt is made to examine if either of these two measures of liquidity is a relevant factor in explaining stock market return.
Design/methodology/approach
The Toda-Yamamoto version of Granger causality test is applied to two sets of data on the Nigerian Stock Exchange (NSE). The available monthly time series data are from 2008 to 2019 while the annual data are from 1986 to 2018. The Toda-Yamamoto test is preferred because it is more robust to integration and cointegration of the variables.
Findings
The results of the Toda-Yamamoto version of the Granger causality test on monthly data reveal no causal relationship between CET and market return, turnover and market return and CET with turnover and market return. These results are consistent with those for several frontier countries reported by Rubio et al. (2005), Hartian and Sitorus (2015), Batten and Vo (2019) and Sterenczak et al. (2020). The results support the conclusion that the Nigerian economy is not fully integrated with the global economy. Market inefficiency due to order imbalances given the nature of the trading system can also explain the reported results. However, the results from annual data do not tally with the monthly results. There is causality running from CET to market return. There is also causality running from turnover to market return. Therefore, both CET and turnover are statistically significant causal predictors of market return. The results from annual data are consistent with those reported by Marozva (2019).
Research limitations/implications
The key limitation is availability of high-frequency transaction-level data to researchers to consider many measures of liquidity that have been employed in developed countries. The research implication is that more researchers will be encouraged to conduct more studies on liquidity and how the study results can drive policy recommendations. The standard asymptotic distribution of underlying the Toda-Yamamoto approach has been found to lead to overrejection.
Originality/value
This study is the first to apply Toda-Yamamoto model on data from Nigeria to investigate the causal relationship between stock market return and liquidity proxied by the CET given the nature of the automated trading system (ATS) in use. The CET is also complemented with the turnover ratio to explore the multidimensional nature of liquidity and its causal relationship with market return. The study is also interpreted as a determination of the integration of Nigeria's economy with the global economy with its implication on investment diversification.
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Femi Emmanuel Ayo, Olusegun Folorunso and Sakinat Oluwabukonla Folorunso
Over the past decade, the cost of product development has increased drastically, and this is due to the inability of most enterprises to locate suitable and optimal collaborators…
Abstract
Purpose
Over the past decade, the cost of product development has increased drastically, and this is due to the inability of most enterprises to locate suitable and optimal collaborators for knowledge sharing. Nevertheless, knowledge sharing is a mechanism that helps people find the best collaborators with relevant knowledge. Hence, a new approach for locating optimal collaborators with relevant knowledge is needed, which could help enterprise in reducing cost and time in a knowledge-sharing environment. The paper aims to discuss these issues.
Design/methodology/approach
One unique challenge in the domain of knowledge sharing is that collaborators do not possess the same number of events resident in the knowledge available for sharing. In this paper, the authors present a new approach for locating optimal collaborators in knowledge-sharing environment using the combinatorial algorithm (CA-KSE).
Findings
The proposed pattern-matching approach implemented in Java is considered efficient for solving the issue peculiar to collaboration in knowledge-sharing domain. The authors benchmarked the proposed approach with its semi-global pairwise alignment and global alignment counterparts through scores comparison and the receiver operating characteristic curve. The results obtained from the comparisons showed that CA-KSE is a perfect test having an area under curve of 0.9659, compared to the other approaches.
Research limitations/implications
The paper has proposed an efficient algorithm, which is considered better than related methods, for matching several collaborators (more than two) in KS environment. The method could be deployed in medical field for gene analysis, software organizations for distributed development and academics for knowledge sharing.
Originality/value
One sign of strength of this approach, compared to most sequence alignment approaches that can only match two collaborators at a time, is that it can match several collaborators at a faster rate.
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Osman M. Karatepe and Olusegun A. Olugbade
This paper aims to examine work engagement as a mediator of the effects of selective staffing, job security, teamwork and career opportunities as the indicators of…
Abstract
Purpose
This paper aims to examine work engagement as a mediator of the effects of selective staffing, job security, teamwork and career opportunities as the indicators of high-performance work practices on absence intentions, service recovery and creative performances.
Design/methodology/approach
Data came from 287 frontline employee–supervisor dyads in the international chain hotels in Nigeria. The direct and mediating effects were assessed using structural equation modeling. The Sobel test was also used to test the significance of each mediating effect.
Findings
The results demonstrate that the simultaneous implementation of selective staffing, job security, teamwork and career opportunities fosters work engagement that in turn leads to reduced absence intentions and results in service recovery and creative performances at elevated levels.
Practical implications
The presence of selective staffing, job security, teamwork and career opportunities enables management to hire individuals high in work engagement. Management should obtain significant feedback about new service ideas and suggestions for novel customer problems through workshops in which employees effectively participate. Management may also let employees with poor performance leave the organization rather than wasting organizational resources to retain them.
Originality/value
Little is known about the underlying mechanism through which high-performance work practices are linked to organizationally relevant and valued attitudinal and behavioral outcomes.