Existing research into student success may not be useful to develop interventions which can improve outcomes for engineering students in Africa, since they fail to account for diversity in local contexts. In our larger project we are using Grounded Theory Methodology (GTM) to investigate student success in African engineering education, interpreted through the experiences of educators. This phase of the project aims to understand better what is meant by “student success” in African engineering education, and to articulate the contexts which impact student success. We recruited participants who had at least five years’ experience in engineering education in African institutions. We conducted a focus group with three participants, and individual semi-structured interviews with four participants. The seven participants are from six African countries and include lecturers as well as academic leaders. Our findings in this paper focus on national and institutional economic contexts. National policies governing funding of university studies, as well as historic funding strategies, contribute significantly to contextual diversity. Institutional contexts include the physical and staffing resources available, whether the institution is private or state-funded, and the socio-economic status distribution of the student body. Based on our analysis of the data, we propose a model in which economic factors are understood as emerging from interactions between national, institutional and personal context.

Context and PurposeThis paper describes a national engineering curriculum renewal initiative designed to meaningfully integrate technical and professional competencies, to prepare graduates for the world of work and the challenges faced by society.The paper presents a descriptive case study to identify the underlying critical success factors of the project. ApproachUsing a social constructivist perspective of curriculum design, we adopt Kotter's model as a theoretical lens for the analysis.The case study draws on the personal reflections of the authors, two members of the project team. OutcomesThe project is described in detail, and the importance and relevance of key phases and steps in the process are highlighted.The crucial roles of broad stakeholder engagement, structured interventions to provoke thinking differently, and sharing of best practices are discussed.Several challenges are identified specifically in relation to stakeholders entering and leaving the process at different points.The paper further shows the additional benefits that can arise through a national initiative of curriculum change. Implications for curriculum renewal projectsOur reflections reveal the differences and similarities between curriculum renewal initiatives at a national and institutional level.A national project, as described in this paper, presents many opportunities, and yet there are complexities that need to be understood and managed throughout the process.We end this paper with insights gained regarding these complexities and how they can be mitigated.

The Engineering Education Research Network in Africa (EERN-Africa) was created to enable connections between practitioners and researchers with a shared interest in African engineering education contexts.Recognising the importance of developing an African voice in the engineering education research space, the EERN-Africa community has interacted in a dynamic and dialogic way with our own teaching and research practices across diverse African contexts, with an ethical commitment to democratic and inclusive community-building.The objective of this paper is to reflect on the current status of the Community of Practice (CoP), and the challenges and opportunities in sustaining and growing the CoP.A collaborative analysis of perspectives on this emerging identity is presented, using an Appreciative Inquiry (AI) methodology and drawing on collective written reflections and discussions.Six broad themes on the value that the CoP has for both individuals and the group were identified: networking, capacity development, emotional support, impact on professional identity, social and environmental impact, and breaking borders.This paper contributes an approach for collaborative capacity-building in EER through a virtual CoP, underpinned by the spirit of ubuntu.

AbstractPolymers are used in various industrial applications due to their ease of production, light weight, and ductility. Fillers such as clays are added to polymers to improve a range of factors such as material processing, thermal properties, fire retardance and cost. However, adding clays may negatively impact the mechanical performance of the composite. In addition, manufacturing parameters, for example, number of extrusions, press time, and so forth may also have an influence on the resulting composite system. This study performs a statistical analysis on a set of previously obtained experimental results, which investigated the influence of various manufacturing, material, and testing parameters on the composite mechanical properties. Exploratory data and statistical analysis techniques are applied to the historical tensile test data to gain insight into the influence on mechanical properties as well as the relationships and interactions between the parameters. Specifically, it is shown that clay loading does not have a statistically significant effect on the composite mechanical properties, which is contrary to literature. Another surprising result is the poor performance of the clay that is compatible with high‐density polyethylene compared to the clay that is compatible with poly vinyl chloride. The contribution of this paper is to demonstrate the usefulness of applying statistical analysis on a large volume of data to understand the diverse correlations between the different variables.

A failure mechanism prevalent with boiler tubes operating in harsh environmental conditions is localized erosion. The consequence of the erosion mechanism is a substantial reduction of the tube thickness, ultimately leading to plastic collapse and consequently rupturing of the tubes. Locating and repairing all the affected tubes within the boiler are time consuming and expensive. It will be worthwhile to rank all the identified flaws so that critical flaws that cannot survive till the next scheduled shutdown are prioritized for repair. Consequently, nonlinear structural analysis was conducted on various boiler tubes that failed by localized erosion. The tubes had a wide range of localized erosion flaws that required a detailed assessment technique. The failure was evaluated numerically using various stress and strain-based failure criteria as well as performing the American Petroleum Institute and the American Society of Mechanical Engineers (API-ASME) fitness-for-service (FFS) assessment on the tubes. A projected time to failure (Pt) for each tube based on the various criteria used in this study was determined. This enabled the ranking of the flawed tubes based on the priority of their repair. The outcome of this study demonstrates the potential for a tool which will enable industry users to prioritize the replacement or repair of critically flawed tubes and avert replacing tubes that are still safe for future operation.

The literature on student success is rich, but most of it is written from the perspective of the Global North.The interventions proposed in the literature may not be practicable or relevant in an African context, or may not be seen by decision makers to be applicable.A preliminary review of the literature shows limited formal African scholarship on engineering student success.We seek to surface and value the expertise on student success that already exists in African engineering institutions, and add it as a contribution to the literature. PURPOSEThe objective of the larger research project is to expand the literature on student success to include perspectives from sub-Saharan Africa.We aim to understand existing African models for student success in engineering, which can enable practical interventions in curriculum design and in institutional support structures.The goal of this paper is to begin to understand student success in the context of three African engineering institutions. METHODOLOGYThis paper presents the first phase of the research, in which we explore the perspectives of a small number of experienced engineering educators from a range of countries and institutions in sub-Saharan Africa, through the medium of an online focus group.This initial unstructured conversation gives us an understanding of the current situation in which educators find themselves.The focus group data was interpreted using Bourdieu's theory of practice, which addresses inequalities in education. OUTCOMESThe focus group data has allowed us to scope the range of contexts in which student success should be considered in sub-Saharan Africa, and identified critical areas for deeper study and further questioning.Based on this, we have developed an interview guide for semistructured interviews with a wider group of participants, and confirmed that Bourdieu's theory of practice is an appropriate theoretical framework for analysing the second phase interview data. CONCLUSIONSIn order for engineering education research to contribute to changes in practice, it needs to be relevant for local contexts.This research begins to develop scholarship around student success from multiple African perspectives, recognising the expertise of African engineering educators, and enriching our understanding of how African engineering institutions engage with this topic.

The transition to university is complex and plays an essential role in determining students’ success in higher education. In South Africa and other global South contexts, students come from diverse backgrounds, and many have to cross what Boaventura de Sousa Santos calls an 'abyssal line'. Students in university in 2020 experienced an abrupt additional transition: to online learning, as universities responded to the Covid-19 pandemic. The current study investigates second-year engineering students' perceptions of the impact of the lockdown on their own studies, and their impressions of how first-year students might have felt this impact, through semi-structured, in-depth interviews. We sought to uncover the particular discourses that students draw on when describing what it was like to experience engineering study within a global pandemic. Throughout the student narratives, we identify a multiplicity of discourses around their identity as university students: as formed through connections with peers, lecturers, the university and the physical campus; as challenged by conflicting demands when studying at home; positioned as able to manage time and work; and vulnerable to threat from failure and the immutable force of online learning. We conclude with implications for universities and student success beyond the pandemic.

Purpose Failure of a critical reinforced concrete beam due to fatigue can have severe safety and production consequences, and preventative repair/replacement of such a beam is expensive. It would therefore be beneficial if repair/replacement can be done based on an accurately and conservatively predicted remaining useful life (RUL). The purpose of this paper is to develop such a model. Design/methodology/approach Condition-based maintenance is a maintenance approach that uses empirical/analytical models and a measurable condition to predict remaining useful life. The P-F curve (condition-life) is a useful tool that can aid in making these decisions. A model to create a P-F curve is developed using rebar fatigue test results (in the form of an S–N curve) and the Palmgren-Miner law of damage accumulation. A Monte Carlo simulation with statistical distributions is employed to provide confidence levels of RUL outputs. Findings An example of how the model can successfully be used in practice is shown in this paper, and a sensitivity study is performed leading to conclusions being drawn with regard to damage tolerant design considerations. Originality/value If a critical reinforced concrete beam fails due to fatigue can have serious consequences. This paper develops a model to help base repair/replacement decisions based on accurately and conservatively predicted RUL. Financial and safety benefits would be gained if this model would be used in practice.

Localized erosion is one of the most common failure mechanisms associated with boiler tubes, driven by impaction of the tube surface by fly ash, soot blowing steam, falling slag or other abrasive substances from the boiler's combustion chamber. The tubes may experience significant localized reduction in their wall thickness, becoming susceptible to plastic collapse and bursting. The replacement of failed tubes is one of the leading causes of unplanned and forced boiler outages in process and power plants. In this study, geometric functions to enable the accurate modelling of boiler tubes with localized erosion flaws were developed from conceptualized models and finite element analyses were conducted on the modelled flawed tubes. The effect of geometry on the stress concentration in the tubes and on the failure pressure associated with the tubes was investigated. Linear elastic stress analysis is sensitive to the flaw geometry - for a representative problem stresses vary 38% as the flaw shape is varied. However, nonlinear elasticplastic analysis shows significantly reduced sensitivity to flaw shape. The collapse pressure of the same representative problem now varies only 2.45% as the flaw shape is varied. This finding was demonstrated for various failure thresholds sourced from the literature, based either on plastic strain or Von Mises equivalent stress, which demonstrates that the failure of the tubes is insensitive to the specific choice of shape parameterization, as long as the minimum remaining wall thickness is matched. The outcome of these investigations gives further insight into the behaviour of tubes with localized external flaws while in service.

Statistical design of experiments (DoE) aims to develop a near efficient design while minimising the number of experiments required. This is an optimal approach especially when there is a need to investigate multiple variables. DoE is a powerful methodology for a wide range of applications, from the efficient design of manufacturing processes to the accurate evaluation of global optima in numerical studies. The contribution of this paper is to provide a general introduction to statistical design of experiments for a non-expert audience, with the aim of broadening exposure in the applied mechanics community. We focus on response surface methodology (RSM) designs — Taguchi Design, Central Composite Design, Box-Behnken Design and D-optimal Design. These different RSM designs are compared in the context of a case study from the field of polymer composites. The results demonstrate that an exact D-optimal design is generally considered to be a good design when compared to the global D-optimal design. That is, it requires fewer experiments while retaining acceptable efficiency measures for all three response surface models considered. This paper illustrates the benefits of DoE, demonstrates the importance of evaluating different designs, and provides an approach to choose the design best suited for the problem of interest.

Laminated composites are complex multifunctional materials and often endure barely visible damage which is characterised by matrix cracks and fiber damage leading to delamination. These composites are often used in safety-critical industries such as aeronautical and automotive industries which makes it crucial to have techniques to assess damage before and during use. This paper presents full-field digital image correlation (DIC) as a method for damage detection in laminated composites under static loading conditions. Full-field DIC is an optical measuring system used to assess deformation data (i.e. displacement and strain) in any component under various loading conditions. Assuming that the damage changes the mechanical properties, the method is applied here to detect changes in stiffness caused by barely visible impact damage in laminated composites. It is shown in the experimental findings that full-field DIC has the capability to detect barely visible damage caused by various impact energies in laminated composites, provided that the excitation or form of loading is applied near the impacted area.

This paper analyses a set of previously obtained experimental results on various clay fillers added to high density polyethylene (HDPE). The composite material was compounded using an extrusion process and manufactured into tensile test samples by means of hot pressing. Various manufacturing parameters (number of extrusions, press time, sample cooling method), material (polymer grade, clay type, clay weight loading) and testing parameters (strain rate) were investigated to determine their influence on the mechanical properties of the composite system. Exploratory data analysis was first employed by graphically representing the data using scatter plots to identify any main characteristics, patterns or anomalies. The statistical analysis was used to quantify the effects of the ultimate tensile strength by first conducting a one way ANOVA analysis before developing a linear model for the response variable analysis. For the percentage elongation to failure, the observations was first grouped into three groups, Brittle, Intermediate or Ductile. A linear discriminant analysis was performed to classify the groups considering a training set of 80% randomly selected observations and testing on the remaining 20%.

This study examines the validity of three international instruments for assessing South African first-year engineering students. The Grit-S, Dweck's Implicit Theories of Intelligence Scale (ITIS), and the Revised Purdue Spatial Visualization Test: Visualisation of Rotations (PSVT:R) were assessed for internal functioning and usefulness in predicting engineering drawing subject marks. Grit-S and ITIS were chosen as they may offer potential areas for intervention to enhance psycho-social adjustment to university. The PSVT: R was administered as it was expected to have a relationship with engineering drawing, and spatial reasoning is a skill that can be taught, which will assist first-year engineering students. The study found that Grit-S was not internally reliable and valid for assessing our engineering students. Both Grit-S and ITIS had low discrimination, with most students strongly agreeing with the statements. The overly positive responses to the instruments led to no predictive power. The PSVT:R had a small but significant relationship to the engineering drawing semester mark as well as evidence for internal reliability and validity. Constructs such as Grit and mindset may need to be recontextualised for the African setting, or the instruments would need to be redesigned to offer greater discrimination power. Only the PSVT:R showed some potential for predicting first-year engineering achievement in the graphics module.

The notion of "resources" is often framed in an economic sense: money, time, equipment and the like. The authors reconceptualise this notion, situating resources as embedded in curricular frameworks, teacher practice and student experience. This leads them to define resources as "the potential to participate in socio-cultural action" which is illustrated in this article through a series of reflections on the part of the authors, all within the context of engineering education. First, they demonstrate that curriculum can be productively thought of as a route marker for the development of resources that students need in order to enact their role as professional engineers. Thereafter, they show that lecturers bring tacit resources of trust, care, creativity and credibility to the teaching and learning space, and that these are necessary to overcome the inertia that often resists the transformation of teaching and learning practice. Finally, they reflect on how students' prior learning experiences can be harnessed as a resource for teaching and learning. In so doing, they present resources as tied to sociocultural practices and personal and institutional histories, and encourage others to take up these ideas so as to consider how resources, viewed in the authors' sense, are valued within (engineering) education.

Boiler tubes used in power plants and manufacturing industries are prone to failure due to the harsh environment they operate in, usually involving high temperature, pressure, and some erosive-corrosive mechanisms. Among the wide range of failures associated with the tubes, localized external erosion continues to be a leading cause of tube leakages and unscheduled boiler outages in power plants and other utilities. This paper lays the foundation to develop a rapid decision-making tool to help prioritize the maintenance, repair, or replacement of these tubes. A failure assessment methodology is proposed, based on the analysis of failed localized thinned tubes from a power plant. Minimal geometric measurements are available for each failed tube (width of flaw, length and flaw and minimal remaining thickness). Finite element models of idealized flaws are created that match the measured data for all the failed tubes. Finite element models with higher remaining wall thickness than the measured values are also constructed. Using two material models, comprehensive nonlinear finite element analyses are conducted on the 160 modeled flawed tubes. The flawed tubes are assessed using the API-ASME fitness-for-service assessment protocol to demonstrate how these flawed tubes would be ranked from most severe to least severe. Allowable wall loss for some of the considered flawed tubes ranges from 44% to 81% of the original wall thickness, indicating that fitness-for-service assessments can establish safe operation even for substantially eroded boiler tubes.

Boiler tubes experience reductions in wall thickness due to erosion and corrosion mechanisms while in use. Due to this localized thinning, the tube becomes susceptible to gross plastic deformation, which eventually causes the tube to rupture. This study presents a non-linear finite element analysis of different geometric configurations of localized boiler tube defects. A defected boiler tube with three variants of the localized thinned area, having different geometrical shapes (flat, n-shape and u shape) was modeled and subjected to a simulated internal pressure. The effect of the defect geometrical shapes and their dimensions (shape aspect ratios, defect length, width and depth) on the failure of the tube while in use were investigated. From the numerical results, the stress concentration factors (SCF) associated with each defect were obtained, and it was observed that these play a more significant role than the amount of material removal in influencing the failure of the tubes. This relationship between the SCF and the defect geometry characteristics helps to predict which tube with a localized thinning geometry is safe for continued operation or will fail, and hence to categorize the severity of defects to prioritize maintenance spending. The result of this work will serve as a guide to categorize the severity of external boiler tube defects. This is relevant whenever a constrained economic environment does not allow for all boiler tubes with defects to be replaced.

Paper presented at the Third International Conference on Composites, Biocomposites and Nanocomposites, 7-9 November 2018, Port Elizabeth, South Africa

1. Abstract Electromagnetic levitation melting is a containerless technique to obtain material properties of reactive, electrically conductive materials that would otherwise result in sample contamination when in contact with a container at high temperatures. The levitation coil geometry, and the magnitude and frequency of the alternating current determine the sample sizes of a specific material that can be levitated as well as the temperature of the levitated sample. The levitation cell is modelled using a one-dimensional analytical approach. This model requires the material properties of the sample and surrounding atmosphere as input variables. Since there is a large amount of uncertainty in measuring these properties they are regularized using experimental data from a known coil design and current. The levitation cell model with regularized material properties is then used in a gradient-based optimization scheme to design a coil for the levitation melting of specified sample size and material. The consequences of using a multistart, gradient-based optimization scheme are reported. Coils are designed to minimize the temperature of the levitated sample or maximize the stability of the sample during levitation. 2.