Inhibition of Stainless Steel Corrosion IN 0.5 M H2SO4 IN The Presence OF C6H5NH2

Inhibition of stainless steel corrosion in 0.5 M H2SO4 by C6H5NH2 (Aniline) at different temperatures was experimentally studied in this paper. Corrosion rate measurements at 28°C, 45°C and 60°C were taken through linear sweep voltametry and utilised for modelling inhibition efficiency and thermodynamic properties in the acidic solution containing different concentrations of the organic chemical. Results showed that inhibition of stainless steel in 0.5 M H2SO4 increased with increasing temperature for most of the different concentrations of C6H5NH2 employed. Optimal inhibition efficiency ranged from η = 26.49% by 0.043 M C6H5NH2 at 28°C, through η = 88.99% by 0.021 M C6H5NH2 at 45°C up to η = 96.68% by 0.043 M C6H5NH2 at 60°C. Also, thermodynamic property analyses showed that apparent activating energy decreases from the uninhibited, 0 M C6H5NH2, to the optimally inhibiting 0.043 M C6H5NH2 containing medium, which suggests C6H5NH2 adsorption drives the inhibition effects observed

Factors associated with antenatal mental disorder in West Africa: a cross-sectional survey

<b>Background:</b> Maternal mental illness is likely to have a profound impact in less developed parts of the world. A mother experiencing mental illness in a low income setting is at risk of providing sub-optimal care for her offspring which can have grave consequences in an environment where poverty, overcrowding, poor sanitation, malnutrition, tropical diseases and a lack of appropriate medical services may be pronounced. Given the profound consequences of antenatal and postnatal mental illness on maternal mental health, foetal wellbeing and childhood growth and development the factors associated with mental illness in a Sub-Saharan setting merit clarification and investigation. <b>Methods:</b> A prospective survey design was conducted in Lagos. Self reporting questionnaire 20 items (SRQ20) assessed the presence of mental illness. The WHO Multi-country Study on Women's Health and Domestic Violence Questions assessed women’s exposure to violence. Numerous variables potentially associated with mental illness including maternal socio-economic factors, maternal characteristics, obstetric variables and the characteristics of previous children were recorded. Direct logistic regression was performed to assess the impact of a number of variables on the likelihood of presence of mental disorder in the population. <b>Results:</b> 189 women were surveyed. 7% met the criteria for experiencing a common mental disorder according to their score on the SRQ-20. Of variables examined only the number of female children and the presence of inter personal violence predicted being a case of mental illness (OR=3.400; 95%CI =1.374 - 8.414 and OR =5 .676; 95%CI = 1.251 - 25.757 respectively). <b>Conclusions:</b> Rates of mental disorder found in our study were lower than those previously observed internationally and in Africa, perhaps reflecting stigma about disclosing symptoms. The predictive nature of violence on mental disorder is in keeping with international evidence. Our study demonstrated that exposure to inter personal violence within the last 12 months and increasing numbers of female children predict the presence of mental illness in a sample of pregnant Nigerian women. Training and education for primary health care and obstetric health workers should highlight these areas

Probability density fittings of corrosion test-data: Implications on C6H15NO3 effectiveness on concrete steel-rebar corrosion

In this study, corrosion test-data of steel-rebar in concrete were subjected to the fittings of the Normal, Gumbel and the Weibull probability distribution functions. This was done to investigate the suitability of the results of the fitted test-data, by these distributions, for modelling the effectiveness of C6H15NO3, triethanolamine (TEA), admixtures on the corrosion of steel-rebar in concrete in NaCl and in H2SO4 test-media. For this, six different concentrations of TEA were admixed in replicates of steel-reinforced concrete samples which were immersed in the saline/marine and the microbial/industrial simulating test-environments for seventy-five days. From these, distribution fittings of the non-destructive electrochemical measurements were subjected to the Kolmogorov-Smirnov goodness-of-fit statistics and to the analyses of variance modelling for studying test-data compatibility to the fittings and testing significance. Although all fittings of test-data followed similar trends of significant testing, the fittings of the corrosion rate test data followed the Weibull more than the Normal and the Gumbel distribution fittings, thus supporting use of the Weibull fittings for modelling effectiveness. The effectiveness models on rebar corrosion, based on these, identified 0.083% TEA with optimal inhibition efficiency, η = 72.17± 10.68%, in NaCl medium while 0.667% TEA was the only admixture with positive effectiveness, η = 56.45±15.85%, in H2SO4 medium. These results bear implications on the concentrations of TEA for effective corrosion protection of concrete steel-rebar in saline/marine and in industrial/microbial environments. © 2014 Indian Academy of Sciences

Electrochemical Performance of Anthocleista djalonensis on Steel-Reinforcement Corrosion in Concrete Immersed in Saline/Marine Simulating-Environment

In this paper, electrochemical techniques were employed to study performance of different concentrations of Anthocleista djalonensis leaf-extract admixtures on the corrosion of steel-reinforcement in concrete immersed in 3.5 % NaCl, for simulating saline/marine environment. Analysed test-results showed that the corrosion rate correlated directly with admixture concentration and inversely with cube of the ratio of standard deviations of corrosion potential and corrosion current. The 0.4167 % A. djalonensis (per weight of cement) exhibited optimal inhibition efficiency, g = 97.43 ± 1.20 %, from analysed experimental data, or 94.80 ± 3.39 %, from predicted correlation model, on steel-reinforcement corrosion in the medium. The other admixture concentrations also exhibited high efficiencies at inhibiting steel-reinforcement corrosion in the chloride contaminated environment. Isotherm fittings of he experimental and predicted performance suggest that they both obeyed the Langmuir adsorption model. Evaluated parameters from the isotherm model indicated favourable adsorption and predominant chemisorption mechanism by this environmentally-friendly inhibitor of steel-reinforcement corrosion in the saline/marine simulating- environment. © 2014, The Indian Institute of Metals - IIM