The effects of chloride concentration, creviced scaling factor and immersion time on the percentage area and maximum depth of attack for Type 304 stainless steel (SS304) in chloride solutions were investigated. The crevice assembly comprised of coupon (SS-304), polytetrafluoroethylene (crevice former) and fasteners (titanium bolt, nut and washers). The full immersion tests were based on ASTM G-78 using full factorial design to study the effects of chloride concentration (1.5, 3.0 and 4.5 w/w%), crevice scaling factor (8, 16 and 24) and immersion time (15, 30 and 45 days) on the percentage area of attack (Y1) and maximum depth of attack (Y2) of SS-304. Data obtained was used to develop and optimize the models of Y1 and Y2 in terms of the three factors using Response Surface Methodology (RSM). The R2 of Y1 and Y2 were 0.98 and 0.91, respectively. The minimum Y1 (5.63%) and Y2 (3.32×10−7 mm) were obtained at 4.5% chloride concentration, 20 scaling factor and 15 days immersion time. The predicted optimal conditions agreed with the experimental results for validation with a maximum absolute relative error of 5.75%.
This study examines the dynamic impacts of oil prices on stock market development in four oil exporting sub-Saharan African countries in the period of 1989-2015. The Arbitrage Pricing Theory (APT) is used as the theoretical framework where stock market prices are hypothesized to be fully reflective of all available information. Static panel data (Pooled OLS, panel Fixed Effect Model, panel Random Effect Model) and dynamic panel model of Generalized Method of Moments (GMM) were employed in the estimation. The estimation of the static panel model shows that oil prices, exchange rates, gross domestic product, inflation and the corruption index have a positive and significant impact on stock market development. However, there is a slight improvement from the estimation of the GMM dynamic panel model which confirmed that oil prices, exchange rates, gross domestic product, investment, inflation and the corruption index have a positive and significant impact on stock market development. The study therefore recommends that investors in selected the Sub-Sahara Africa (SSA) stock market need to be cognizant of the varying impacts of macroeconomic indicators, particularly those that have been found to exert strong influence on stock returns like oil prices, exchange rates, inflation and the corruption index.
Background. Conflicts across professional workgroup and hierarchies inundate the clinical workplace. Early Career Doctors (ECDs) are also affected either as victims or as a provocateur/perpetrator. The effects of conflict at their workplaces have both significant positive and negative dimensions and impacts on ECDs. Little has been reported about conflict among ECDs in Nigeria.
Thus, this study explored the issue of conflict and conflict resolution among ECDs in Nigeria, in a bid to elicit information on the causes, consequences, perpetrators and victims.
Method. This was a qualitative study, using Focus Group Discussions (FGD) to explore information on conflict and conflict management among purposively selected key respondents (n = 14) from seven tertiary hospitals in Nigeria. The respondents are ECDs who were leaders and representatives of other ECDs in their various hospitals. Two FGDs were conducted.
Results. The result showed that conflict is inescapable in clinical settings and occurred at different levels. The perpetrators are varieties of health workers, and most are task-related conflicts, although there are relational ones. The conflicts with the government on labour-related issues are also frequent. The lack of job description and specification and power struggle among others were highlighted as the drivers of conflicts between ECDs and other health-workers. Conclusion. The findings of the study were discussed, and suggestions were made to reduce its effect, which would require structural solutions to mitigate at different levels and the diverse players in the health sectors.