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This paper aims to investigate and explain the dual fracture behaviour of PA12 specimens sintered by selective laser sintering (SLS) as a function of wall thickness and build direction with a powder mixture 30:70. To achieve this objective, research related to chemical, thermal and structural behaviours as a function of the input variables was carried out to describe and explain why ductile-fragile behaviour occurs during fractures under uniaxial tension manufactured via a methodology of material analysis and manufacturing processes.

The factorial design 32 relates the fracture of PA12 tensile specimens to the horizontal, transverse and vertical build directions at 2.0, 2.5 and 3.0 mm thicknesses, respectively. Fractographic images revealed the fracture surfaces and their dual ductile-fragile behaviour related to the specimens’ measured crystalline, thermal, surface and chemical properties.

The study showed that thermal property variables differ depending on the input variables. The wall thickness variable affected this morphology the most, showing the highest percentage of the ductile area, followed by the transverse and vertical directions. It was determined that the failure in the vertical direction is due to crystalline gradients associated with the layer-by-layer construction process. The pore density may be closely related to generating ductile and brittle areas.

In this paper, fracture characterisation is performed based on the mechanical, chemical, structural, thermal and morphological properties of PA12 manufactured by SLS. In addition, a heatmap of porosities in cross-sections is constructed using a machine learning model (k-means) related to dual fracture behaviour. This research revealed significant differences in the fracture type according to the build direction. In addition, thin-section fractography provides a more detailed explanation of the fragile behaviour of the vertical direction associated with crystalline changes due to the direction of the sintering layers.

Wine consumption is declining, while cannabis use among young adults in Germany has surged. With new laws partially legalising recreational cannabis, advocates claim it could replace alcohol, offering health benefits and cost savings. However, concerns remain that cannabis might increase alcohol consumption and associated health risks. Despite recognition of both substitute and complementary relationships between cannabis and alcohol, data on the cannabis–wine relationship is scarce. This study aims to understand the motivations behind wine and cannabis consumption, segment wine drinkers by those motives, profile wine drinkers who also consume cannabis and determine whether wine and cannabis act as substitutes or complements across distinct consumer groups.

The authors conducted an online survey using random sampling and used cluster analysis to identify consumer segments based on motivations for wine consumption. Exploring various variables, including consumption motives, behavioural patterns and socio-demographics, the authors also examined cannabis consumption among wine drinkers.

This study surveyed 523 German wine drinkers aged 20–60 years, including 215 cannabis users. Four consumer segments emerged: “adaptive conformists”, “expansive strategists”, “self-conscious hedonists” and “ambivalent drinkers.” Three segments preferred wine for social and enhancing effects. “Adaptive conformists”, the group with the most cannabis users, sought negative reinforcement like conformity or coping. The “adaptive conformists” and “expansive strategists” show the tendencies of a complementary cannabis–wine relationship.

This study pioneers the use of the Marijuana Motives Measure scales, developed by Simons et al. (1998), within the motivational framework by Cox and Klinger (1988) and Cooper et al. (2015), for wine drinkers. To the best of the authors’ knowledge, this is also the first to categorise wine drinkers into segments based on MMM scales for both wine and cannabis and segment wine consumers using cannabis.