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The purpose of this sudy is to provide a complete optimization-based methodology to design waveguides with metamaterial walls. The present methodology is based on optimization. Indeed, the inverse problems of design are formulated as nonlinear black-box optimization problems with constraints. Two inequality black-box constraints are taken into account as penalized terms that are added to the objective function when the constraints are not satisfied. The numerical steps are done by using a finite element method solver (GetDP). Thus, different optimization software are tested to solve the nonlinear black-box optimization problems such as IPOPT, NLOPT and NOMAD from the Opti ToolBox in MatLab.

In this work, a methodology to design waveguides with metamaterial walls is proposed. The aim is to solve an inverse problem to find the best design where the electric field cartography is the closest to an imposed one.

The present methodology is applied to solve inverse problems of design and satisfactory results were provided by the three solvers IPOPT, NLOPT and NOMAD. Those numerical experiments show that NOMAD is the most efficient method to optimize the design of those cylindrical waveguide structures with metamaterial walls.

The model is set to find solutions using a specific pattern of metamaterials. This is promising to take those geometries as variables of the optimization problems. Moreover, in this exploratory work, no constraint on the fabrication limits has been taken into account.

The originality is to formulate design problems of waveguide with metamaterial walls into optimization problems. These optimization problems are difficult to solve because the objective function and two inequality constraints are computed via a numerical simulation code based on finite element methods. Thus, an original approach based on penalization is implemented and three optimization software are used. Hence, the authors propose an optimization-based methodology and apply to solve two inverse problems of design.

This paper aims to address the need to adopt circular economy models in the urban development and infrastructure of Gulf Cooperation Council (GCC) countries – Bahrain, Kuwait, Oman, Qatar, UAE and Saudi Arabia. The purpose is to provide insights into the progress, challenges and potential benefits of transitioning from a linear to a circular economic model in response to the environmental challenges posed by rapid economic development and population growth in the GCC region. The study emphasizes the relevance of this research in fostering economic diversification, mitigating ecological concerns and attracting sustainable investments.

The study adopts a qualitative approach to investigate the adoption of circular economy principles in each GCC country’s urban development and infrastructure. It details the specific strategies and initiatives undertaken by Bahrain, Kuwait, Oman, Qatar, UAE and Saudi Arabia. The research methodology includes a Systematic Literature Review (SLR), thematic, comparative and individual analysis of their goals, progress and the unique approaches employed. Additionally, a SWOT analysis is conducted to identify strengths, weaknesses, opportunities and threats associated with adopting circular economy models in the GCC region.

The case studies reveal each GCC country’s diverse approaches and progress in adopting circular economy models. Bahrain aims for carbon neutrality by 2060, Kuwait prioritizes sustainability in urban development, Oman focuses on waste reduction, Qatar integrates circular economy principles into its Vision 2030 initiative and Saudi Arabia explores closed-loop material flows. Whereas, the UAE focuses on infrastructure development with unique technological advancements in the near future. Despite common challenges such as traditional linear models and economic obstacles, the benefits of transitioning to circular economies in the GCC region are substantial. These include social, environmental and economic advantages, emphasizing sustainable growth, resource efficiency and enhanced environmental protection.

This paper contributes original insights into the adoption of circular economy models in the GCC region, providing a clear and succinct case for its value. The research underscores this transition’s economic, environmental and social benefits. It emphasizes the significance of sustainable resource management and economic opportunities while acknowledging challenges such as implementation obstacles and potential business impacts. The study invites reflection on future research steps, fostering a balanced and fair analysis of the value of the results. It positions the adoption of circular economy models as a crucial step toward achieving economic diversification, and environmental sustainability and attracting green investments in the GCC region.

After completion of the case study, students will be able to examine the financial implications of Maghreb Steel’s substantial investment in the Blad Assolb complex in 2007 within the restructuring plan; explore how this decision influenced the company’s financial health and strategic position in the steel market, within the context of the restructuring plan; assess the impact of the 2008 economic crisis within the restructuring plan; analyze how the crisis affected the company’s pricing strategies, profitability and overall business strategy; investigate the financial and strategic consequences of the hot rolling activity initiated as a result of the Blad Assolb project within the company’s restructuring plan; and critique how this venture impacted the company’s operations, cost structure and competitiveness in the steel industry, aligned with the restructuring plan.

This case study deals with the only flat steel producer in Morocco: Maghreb Steel, the Moroccan family-owned company created in 1975 by the Sekkat family. It was a leading steel company. At the beginning, the company was specialized in the field of steel tubes, but thanks to its growth ambitions, the Sekkat family had made Maghreb Steel a major player in the Moroccan steel sector. In the same logic of development, the top management of Maghreb Steel launched in 2007 in the adventure to create the first production complex of cold rolling in Morocco – an investment that pushed Maghreb Steel to resort to a debt of more than 6bn dirhams (DH) with a consortium of six banks and would have allowed the company a huge leap in growth, except that the decision-makers of the group Sekkat could not see coming the economic crisis of 2008 causing the fall of steel prices by 62% compared to 2007. Thus, from its effective launch in 2010, the activity of hot rolling would become, for the company, a regrettable orientation. Moreover, the national market could not absorb all the production of the complex that the company called Blad Assolb. In response to this difficult situation, Maghreb Steel decided to store its goods to avoid selling at a loss. Faced with this situation of sectoral crisis and deterioration of its activity, Maghreb Steel lost its ability to honor its financial commitments with the banking consortium. From then on, the company became a case of failure, and the recovery measures had not ceased to be duplicated by the various stakeholders: State, Sekkat family, creditors and management of the company, having only one objective in mind: Save Maghreb Steel! This said, the present case study is dedicated to the financial and strategic analysis of the current situation and the evolution of the company throughout the crisis period to finally propose a suitable recovery plan to save Maghreb Steel.

The case study can be taught to students of master’s degrees in financial management as a synthesis of finance courses. It can also be used to train executives and managers working in family businesses as part of professional certification training.

Teaching notes are available for educators only.

CSS 1: Accounting and finance.