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Abstract: A resilient supply chain is crucial for economic growth and the well-being of economies. However, it contributes to environmental challenges, such as resource extraction, material usage, climate change and biodiversity. This Special Volume of the Journal of Logistics, Supply Chain, Sustainability, and Global Challenges explores current research directions and challenges while offering solutions for sustainable supply chains. The volume examines existing European policy directives and strategies to comprehensively understand sustainable supply chain requirements. It conducts a content analysis of the current research in the field. The authors present valuable theoretical insights and empirical case studies addressing the interplay between sustainable supply chains, economic growth, and environmental impact mitigation. The papers in this Special Volume highlight the holistic and interconnected nature of the supply chain field and emphasise that there is still significant potential for improving supply chain processes to enhance their sustainability.
Keywords: sustainable supply chains, economic growth, environmental impact, industry 4.0
Published in DKUM: 01.10.2024; Views: 0; Downloads: 1
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Abstract: Cladding with a stick electrode is one of the oldest arc processes for adding a deposit on a base material. The process is suitable for outdoor working, but the disadvantages are low productivity and large dilution rates. In this work, a simple solution is proposed, which would enable cladding of a larger area with one pass and decrease the dilution rate at the same time—a new type of electrode was developed, exhibiting a rectangular cross-section instead of a round one. Hardfacings, welded with E Fe8 electrodes according to EN 14 700 Standard were welded on mild steel S355 J2 base material with three different coated stick electrodes. The first one was a commercially available, standard, round hardfacing electrode, the second was the same, but with a thinner coating, and the third one was a newly developed rectangular electrode. All three types had equal cross-sections of the metallic core and the same type of coating. Manufacturing of the rectangular electrodes in the laboratory is explained briefly. One- and multi-layer deposits were welded with all three types. Differences were observed in the arc behavior between the round and rectangular electrodes. With the rectangular electrode, the microstructure of the deposit was finer, penetration was shallower, and dilution rates were lower, while the hardness was higher, residual stresses predominantly compressive, and the results of instrumented Charpy impact tests and fracture mechanics tests were better.
Keywords: hardfacing, dilution rate, hardness, Charpy impact toughness, residual stress, fracture toughness
Published in DKUM: 14.05.2024; Views: 298; Downloads: 16
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Abstract: A hot-rolled clad plate made of 316L stainless steel and S355 carbon steel was produced in a real industrial environment via GMAW welding, vacuuming, preheating to 1240 °C, and hot-roll bonding on four stand plate mills in nine passes with reduction rates between 20-6% per pass. The clad plates were solution annealed to achieve the usual delivery condition. Ultrasound testing showed a bonding rate of 100%. Metallographic examination revealed predominantly low concentrations of oxides at the interface. The tensile strength of the bond reached 155 MPa. The shear strength always satisfied the requirements of ASTM A264. It was observed that the concentration of oxide particles influenced the shear strength strongly. The lowest measured value was 172 MPa. Specimens notched in the base material and specimens notched in the clad layer were used in the Charpy impact test. In every case, only the notched layer broke, while the other layer was only bent. The absorbed energies were always higher than those of each material alone. Fracture mechanic tests gave similar results. The crack could not propagate from the notched layer into the other one, regardless of the material of the notched layer. Instead, delamination occurred. Due to delamination, K1c could not be determined, so KQ was given instead.
Keywords: clad plate, hot-roll bonding, shear strength, tensile strength, impact toughness, crack propagation
Published in DKUM: 28.03.2024; Views: 210; Downloads: 11
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Abstract: The study presents an extensive mechanical and computational characterisation of novel cellular metamaterial with axisymmetric chiral structure (ACS) at different strain rates. The Direct Impact Hopkinson Bar (DIHB) testing device was used for impact testing up to 21 m/s striker speed, which was insufficient to reach the shock deformation regime. Thus, using computational simulations to estimate the structure behaviour at high strain rates was necessary. Experimental and computational results showed that all ACS structures exhibit a nominal stress–strain relationship typical for cellular materials. As the loading conditions shifted to a dynamic regime, the micro–inertia effect became increasingly pronounced, leading to a corresponding rise in structure stiffness. The Poisson's ratio in all ACS increases gradually, making them superior to traditional cellular materials, which experience a sudden increase in Poisson's ratio during loading. Additionally, the study found that the structures exhibited a rise in the auxetic effect with an increase in strain rate, highlighting the benefits of axisymmetric structures in high-loading regimes. Overall, the obtained results provide valuable insights into the mechanical properties of ACS under different loading regimes and will contribute to further design improvements and the fabrication of novel ACS metamaterials.
Keywords: axisymmetric chiral structure, auxetic, chiral unit cell, impact testing, dynamic characterisation, finite element simulations
Published in DKUM: 15.02.2024; Views: 345; Downloads: 22
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Abstract: This paper reviews resident tourism attitude research through the lens of the individual- and community-level perceived impacts of and responses to tourism. It explores how perceived impacts of tourism and responses to tourism development have been conceptualised and measured in the existing resident attitudes models published between 1990 and 2020. Three categories of variables were identified and used: antecedent variables, tourism impact variables, and dependent variables. The latter three categories are used to discuss the research topic from the lenses of improvements in measurement instruments. Finally, the paper suggests rethinking the overall conceptualisation of residents’ perceptions of and reactions to tourism – it proposes future research directions to distinguish between individual-level and community-level effects and reactions.
Keywords: resident attitudes, support for tourism, tourism impact, personal benefit, host community, literature review
Published in DKUM: 18.01.2024; Views: 316; Downloads: 16
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