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The aim is to expand the challenge-hindrance framework and develop a coherent theoretical framework that explains individual differences in the way small business owners appraise their job demands. Literature has shown that dealing effectively with job demands leads to competitive advantage and depends on individual appraisals.

For this qualitative study, 20 in-depth interviews were analyzed using a partially grounded theory approach.

Open and axial coding revealed a broader range of demands than have hitherto been studied, related to actions rather than job characteristics. Selective coding confirmed expectations based on the Conservation of Resources Theory that appraisals of demands differ between business owners and change over time depending on role identities, and material, social, personal and energy resource levels, via the valence (identities) and degree of anticipated outcomes. Business owners appraised certain demands as challenging when they were co-occurring with other demands usually categorized as challenges, whereas these same demands were appraised as hindering when co-occurring with demands usually categorized as hindrances.

The results imply that appraisals can be influenced by societal context, life events, processes of formal and informal learning, personal growth and aging. These topics would be interesting avenues for future research.

The results of this study challenge our understanding of job demands in general and current categorizations of job demands as challenges versus hindrances in specific, by providing an in-depth, contextualized and dynamic view of the appraisal of demands related to owning and running a business.

The purpose of this paper is to review cases of artificial reefs built through additive manufacturing (AM) technologies and analyse their ecological goals, fabrication process, materials, structural design features and implementation location to determine predominant parameters, environmental impacts, advantages, and limitations.

The review analysed 16 cases of artificial reefs from both temperate and tropical regions. These were categorised based on the AM process used, the mortar material used (crucial for biological applications), the structural design features and the location of implementation. These parameters are assessed to determine how effectively the designs meet the stipulated ecological goals, how AM technologies demonstrate their potential in comparison to conventional methods and the preference locations of these implementations.

The overview revealed that the dominant artificial reef implementation occurs in the Mediterranean and Atlantic Seas, both accounting for 24%. The remaining cases were in the Australian Sea (20%), the South Asia Sea (12%), the Persian Gulf and the Pacific Ocean, both with 8%, and the Indian Sea with 4% of all the cases studied. It was concluded that fused filament fabrication, binder jetting and material extrusion represent the main AM processes used to build artificial reefs. Cementitious materials, ceramics, polymers and geopolymer formulations were used, incorporating aggregates from mineral residues, biological wastes and pozzolan materials, to reduce environmental impacts, promote the circular economy and be more beneficial for marine ecosystems. The evaluation ranking assessed how well their design and materials align with their ecological goals, demonstrating that five cases were ranked with high effectiveness, ten projects with moderate effectiveness and one case with low effectiveness.

AM represents an innovative method for marine restoration and management. It offers a rapid prototyping technique for design validation and enables the creation of highly complex shapes for habitat diversification while incorporating a diverse range of materials to benefit environmental and marine species’ habitats.