6 research outputs found

    The influence of chemistry inhomogeneity on microstructure development and residual stress

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    The chemistry distribution is of importance in the welding process. By varying the chemical composition, the evolution of microstructure and the residual stress change correspondingly. To examine the effect of chemistry, a three-dimensional metallo-thermo-mechanical model is created. The model is established according to a bead-on-plate welding experiment. Samples of S700 steel are manufactured by gas metal arc welding (GMAW). In total, three welds with three heat inputs were conducted so that different chemistries are obtained. The final weld geometry and the uniform chemistry in the fusion zone (FZ) are predicted by the software SimWeld. The parameters in the double ellipsoidal heat source are also calibrated by SimWeld. An inhomogeneous chemistry field is created using the data predicted by SimWeld and the chemical composition of base material (BM), and is further imported to the coupled model by writing user subroutine in ABAQUS. The metallurgical algorithm is implemented in the same way for calculating the phase volume fraction using both the homogeneously and the inhomogeneously distributed chemistry fields. After the temperature and microstructure are determined, the mechanical analysis is conducted using linearly interpolated material properties. Finally, the results of microstructure distribution and the residual stress predicted for homogeneous and inhomogeneous field are compared to clarify the influence of chemical composition

    Assessing the impact of fusion-based additive manufacturing technologies on green supply chain management performance

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    Funding Information: In√™s A. Ferreira acknowledges financial support from Funda√ß√£o para a Ci√™ncia e Tecnologia for funding PhD Grant (REF: SFRH/BD/145448/2019). The authors In√™s A. Ferreira, J.P. Oliveira and Helena Carvalho acknowledge Funda√ß√£o para a Ci√™ncia e a Tecnologia (FCT‚ÄďMCTES) for its financial support via the project UIDB/00667/2020 (UNIDEMI). J.P. Oliveira acknowledges funding by national funds from Funda√ß√£o para a Ci√™ncia e a Tecnologia, I.P., in the scope of the projects LA/P/0037/2020, UIDP/50025/2020 and UIDB/50025/2020 of the Associate Laboratory Institute of Nanostructures, Nanomodelling and Nanofabrication‚Äďi3N. This activity has received funding from the European Institute of Innovation and Technology (EIT) ‚Äď Project Smart WAAM: Microstructural Engineering and Integrated Non-Destructive Testing. This body of the European Union receives support from the European Union‚Äôs Horizon 2020 research and innovation program. Publisher Copyright: ¬© 2022, In√™s A. Ferreira, J.P. Oliveira, Joachim Antonissen and Helena Carvalho.Purpose: This paper aims to identify the impacts of wire and arc additive manufacturing (WAAM) technology on the green supply chain management (GSCM) performance. Also, it intends to identify the most essential WAAM capabilities. Design/methodology/approach: An exploratory case study related to a metallurgical company using WAAM technology to repair metallic components was developed. A research framework to identify WAAM production capabilities and the different GSCM performance criteria was proposed based on the current state of the art. Primary qualitative data provided evidence for developing seven propositions relating WAAM capabilities to GSCM performance. Findings: The paper provides empirical evidence relating to how WAAM production capabilities impact the different performance criteria of the GSCM performance. The results show that ‚Äúrelative advantage‚ÄĚ and ‚Äúsupply-side benefits‚ÄĚ are critical capabilities developed through WAAM. Furthermore, most of the capabilities regarding ‚Äúrelative advantage‚ÄĚ and ‚Äúsupply-side benefits‚ÄĚ promote a higher GSCM performance. Research limitations/implications: This research was carried out using a single case study research design and using qualitative data. Thus, future works are encouraged to test the propositions empirically using quantitative methodologies. Practical implications: The case study findings support that most WAAM production capabilities promote a higher GSCM performance. Managers could use this research to understand the capabilities developed by this fusion-based additive manufacturing (AM), become aware of the implications of new technology adoption on the supply chain environmental externalities, and develop new business models based on the WAAM capabilities. Originality/value: This research contributes to expanding the state-of-the art related to WAAM technology by evidencing the relationship between adopting this fusion-based AM technology and green supply chain practices. Also, it provides a set of seven propositions that could be used to theorise the impacts of WAAM adoption on the GSCM performance.publishersversionpublishe

    Development of an in vivo lipopolysaccharide inflammation model to study the pharmacodynamics of COX-2 inhibitors celecoxib, mavacoxib, and meloxicam in cockatiels (Nymphicus hollandicus)

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    Nonsteroidal anti-inflammatory drugs (NSAIDs) are used frequently in avian medicine for their antipyretic, analgesic, and anti-inflammatory properties during surgery and for diseases that cause tissue damage and inflammation. NSAIDs inhibit cyclooxygenase (COX) enzymes, which are responsible for the induction of pyresis, pain, and inflammation. In our study, a lipopolysaccharide-induced (LPS) pyresis model was optimized using cockatiels (Nymphicus hollandicus) as subject birds (four males/three females) and validated in two females and one male, characterized by an intravenous bolus injection of LPS (7.5 mg/kg) administered at T-0 and T-24 (24 hours following the first LPS injection). To demonstrate the feasibility of the model to assess pharmacodynamic (PD) parameters of different NSAIDs, mavacoxib 4 mg/kg (four males/four females), celecoxib 10 mg/kg (four males/four females) and meloxicam 1 mg/kg (four males/four females) were evaluated in the model at dosages used frequently in practice. The PD parameters (body temperature, mentation, posture, preference of location in the cage, and prostaglandin E-2 [PGE(2)] plasma concentrations) were determined for 10 hours following the second LPS injection. At the doses evaluated, mavacoxib and celecoxib significantly reduced LPS-induced hypothermia, but had no clear effects on other clinical signs of illness. In contrast, no effect on hypothermia or clinical appearance was observed in the LPS-challenged cockatiels treated with meloxicam. All three NSAIDs were able to inhibit the increase in LPS-induced PGE2 plasma concentrations, yet the effect was most pronounced in the birds treated with meloxicam. Consequently, the presented model opens perspectives for future dose-effect PD studies to optimize analgesic protocols in cockatiels

    Life cycle sustainability assessment of repair through wire and arc additive manufacturing

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    Extending the useful life of a product through repair can significantly reduce the environmental impact associated with its production, and it can be less resource intensive than other environmentally virtuous practices like recycling. Wire and arc additive manufacturing (WAAM) appears to be a promising approach in this context, being characterized by high-resource efficiency, flexibility to perform repairs, and having recently gained industrial maturity. In this work, a methodology to assess the life cycle environmental sustainability of repaired products through WAAM will be presented with a real-world, industrial case study
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