Laser powder bed fusion of INCONEL® 718: optimization of process parameters and residual stress analysis before and after heat treatment

Metals Additive Manufacturing (AM) is a “flourishing” technology, developing fast and successfully. Laser Powder Bed Fusion (LPBF) is among the most used metals AM processes in industry. Inconel® 718 (IN718) is a nickel-based superalloy that maintains its exceptional properties at high and low temperatures, thereby, it is a material commonly used to fabricate high performance components. The purpose of this work is to study the residual stress (RS) evolution of IN718 parts fabricated by LPBF, before and after heat treatment. Firstly, specimens with different combinations of parameters were fabricated to select the optimal LPBF process parameters. With the results from that part of the work, the influence of the individual process parameters on the porosity was studied. Then, new specimens were fabricated with the selected parameters and the RS analyzed by the hole-drilling strain-gage method, in as-built, solution annealed (SA) and SA plus double-aged (DA) conditions. It was concluded that increasing the scanning speed contributes to the reduction of the porosity. Also, for lower scanning speeds, 400 mm/s and lower, a hatching distance of 0.13 mm was defined as optimal. For higher scanning speeds, 600 and 800 mm/s, no relevant influence of the hatching distance, from 0.05 to 0.11 mm, on the porosity was observed. Laser power and layer thickness were not studied. Larger pores were found in specimens with higher porosity. Also, the specimens with higher porosity presented irregular pores and with lower porosity presented spherical-like pores. Regarding the RS evolution, as-built top surface presented uniform RS distribution of approximately 400 MPa. Lateral surface presented anisotropic distribution, with RS magnitudes of 600 to 800 MPa in build direction and 200 to 300 MPa horizontally. After the SA heat treatment, the RS decrease greatly to values between 50 – 200 MPa. Series of carbides were found at the grain boundaries, which were attributed as the cause for oscillations in the RS profile. SA plus DA condition presented RS between 10 to 50 MPa. Heat-treated specimens revealed compressive RS at immediately near the surface.A fabricação aditiva (FA) de metais é uma tecnologia “florescente”, em rápido desenvolvimento e com sucesso. Fusão a laser em leito de pó (LPBF) está entre os processos de FA de metais mais usados na indústria. Inconel® 718 é uma superliga à base de Nickel, que mantém as suas propriedades excecionais a altas e baixas temperaturas, desse modo, é comummente usada para produzir componentes de alto desempenho. O objetivo deste trabalho é estudar a evolução das tensões residuais (TR) de partes produzidas por LPBF, antes e pós tratamento térmico. Primeiramente, produziram-se amostras com diferentes combinações de parâmetros do processo LPBF para selecionar os melhores parâmetros. Com os resultados obtidos dessa parte do trabalho, foi estudada a influência na porosidade dos diferentes parâmetros. Então, produziram-se novas amostras com os parâmetros selecionados e foram analisadas as TR pelo método do furo cego incremental, nas condições: “as-built”, recozido (SA) e SA mais envelhecimento duplo (DA). Concluiu-se que o aumento da velocidade de varredura contribuí para a redução da porosidade. Também, para velocidades mais baixas, 400 mm/s e abaixo, a distância entre passagens de 0.13 mm foi definida como ótima. Para velocidades mais altas, 600 mm/s e 800 mm/s, a influência da distância entre passagens, de 0.05 a 0.11 mm, na porosidade é desprezível. A potência do laser e a espessura das camadas não foram estudados. Poros maiores foram observados nas amostras com maior porosidade. Também, as amostras com maior porosidade exibiram poros irregulares, e com menor porosidade poros esféricos. Em relação à evolução das TR, a face superior “as-built” apresentou uma distribuição das TR uniforme de aproximadamente 400 MPa. A face lateral apresentou distribuição anisotrópica, com TR entre 600 e 800 MPa na direção de deposição, e entre 200 e 300 MPa horizontalmente. Nas amostras SA, as TR reduziram substancialmente para valores entre 50 e 200 MPa. Foram detetados conjuntos de carbonetos, aos quais se atribuiu a ocorrência de oscilações no perfil das TR. A condição SA mais DA apresentou TR entre 10 e 50 MPa. As amostras tratadas termicamente revelaram TR à compressão bem próximo da superfície

Data on network of live cattle exports from Brazil

This report describes the network of live cattle exports from Brazil using Microsoft Office Excel® files, Terraview®, Maporama®, Pajek® and Google Maps® softwares. The database contains estimates obtained from the Ministry of Agriculture, Livestock and Food Supply (MAPA) and underwent descriptive, spatial and flow network. The network of live cattle exports from Brazil was determined using data from 27,517 Animal Transit Certificates (ATC) and 579 Veterinary Certificate for International Trade. International departure points, municipalities and states of origin, destination countries, purpose of export and compliance with sanitary requirements for exports, cattle movement and the main transportation corridors were showed through flow network. The states that exported live cattle were Pará, Rio Grande do Sul, Tocantins, São Paulo, Minas Gerais and Maranhão. Vila do Conde Port, located in Barcarena municipality in the state of Pará, was the main international departure point of animals, which were intended mostly for immediate slaughter in the importing country. The internal cattle transportation corridors of the main counties and farms that provide animals for exports in 2009 were mapped

Produção de estórias e o gosto de afazer: exercícios de imaginação em escrita para a educação em direitos humanos

Os direitos humanos podem ser compreendidos como um conjunto de princípios que operam no plano formalizado da linguagem e também em um sistema de significação mais amplo, não formalizado. Este artigo apresenta uma proposta de formação em direitos humanos baseada na produção de estórias e voltada à educação escolar de jovens. Elaborada no âmbito do grupo de pesquisas em linguagem e direitos humanos (IEL/Unicamp), a proposição se baseia didática e pedagogicamente no pensamento de Hannah Arendt e almeja expor um projeto político de ensino viável, que enfoque a disciplina de Língua Portuguesa – sem ignorar seu potencial interdisciplinar – para a produção do que chamamos de “exercícios de imaginação” em escrita. Nossa proposta, portanto, tenciona promover reflexões, em sala de aula, acerca das conceituações jurídicas, filosóficas e subjetivas dos direitos humanos e das formas sociais da diferença e da universalidade, além de estimular, na escrita, inversões de perspectiva, adotando-se o “eu” como enunciador de um “outro”. Tais inversões funcionariam como aparato propício à sensibilização e à busca de uma “mentalidade alargada”, mais consciente da alteridade e apta à apreensão dos dilemas individuais e coletivos do mundo contemporâneo

Surgical aortic valve replacement and patient-prosthesis mismatch a meta-analysis of 108 182 patients

OBJECTIVES: This study sought to evaluate the impact of patient–prosthesis mismatch (PPM) on the risk of perioperative, early-, mid- and long-term mortality rates after surgical aortic valve replacement. METHODS: Databases were searched for studies published until March 2018. The main outcomes of interest were perioperative mortality, 1-year mortality, 5-year mortality and 10-year mortality. RESULTS: The search yielded 3761 studies for inclusion. Of these, 70 articles were analysed, and their data were extracted. The total num- ber of patients included was 108 182 who underwent surgical aortic valve replacement. The incidence of PPM after surgical aortic valve re- placement was 53.7% (58 116 with PPM and 50 066 without PPM). Perioperative mortality [odds ratio (OR) 1.491, 95% confidence interval (CI) 1.302–1.707; P < 0.001], 1-year mortality (OR 1.465, 95% CI 1.277–1.681; P < 0.001), 5-year mortality (OR 1.358, 95% CI 1.218–1.515; P < 0.001) and 10-year mortality (OR 1.534, 95% CI 1.290–1.825; P < 0.001) were increased in patients with PPM. Both severe PPM and moderate PPM were associated with increased risk of perioperative mortality, 1-year mortality, 5-year mortality and 10-year mortality when analysed together and separately, although we observed a higher risk in the group with severe PPM. CONCLUSIONS: Moderate/severe PPM increases perioperative, early-, mid- and long-term mortality rates proportionally to its severity. The findings of this study support the implementation of surgical strategies to prevent PPM in order to decrease mortality rates

The Advertisement Calls and Distribution of Two Sympatric Species of \u3cem\u3eChiasmocleis\u3c/em\u3e (Méhely 1904) (Anura, Microhylidae, Gastrophryninae) from the Atlantic Forest

The advertisement calls of Chiasmocleis cordeiroi and C. crucis are described for populations from the municipalities of Igrapiúna and Camacan, respectively, state of Bahia, Brazil. Both calls consist of multipulsed notes produced in series. Differences between the two calls are: dominant frequency, higher in C. cordeiroi (range 4500-4898 Hz; C. crucis range 4069-4435 Hz); note rate, higher in C. cordeiroi (range 6.20--7.46 s/note; C. crucis range 5.17-5.59 s/note); pulse rate, higher in C. cordeiroi (151.82-194.83 s/note; C. crucis range 125.30- 142.12 s/note); and the structure of the modulation patterns of the notes. Moreover, the advertisement calls of C. crucis and C. cordeiroi are more similar than the calls of all syntopic congeners. Furthermore, the current distribution of both species was extended

Desafios Atuais em Reprodução Assistida: Técnicas Avançadas e Questões Éticas

Purpose: The purpose of this article is to explore the complexities of assisted reproduction, examining technical challenges, ethical issues, psychosocial impact, and future prospects. It seeks to provide a comprehensive overview of the field, promoting understanding of the scientific, ethical and social implications associated with assisted reproduction, while highlighting the importance of responsible innovation and holistic care. Methodology: A systematic literature review was carried out covering the years from January 2010 to December 2023. The study was based and guided by the question mentioned throughout the article. Results: This article aims to address the nuances of assisted reproduction, covering technical challenges, ethical issues, psychosocial impact and future perspectives. It seeks to offer a complete overview of the field, highlighting the scientific, ethical and social implications, and emphasizing the importance of responsible innovation and holistic care. Conclusion: Future perspectives in assisted reproduction bring scientific advances, such as artificial intelligence and advanced techniques. However, innovations demand an ethical approach in areas such as gene editing. Mental health becomes central, requiring sensitive treatment environments. Collaboration between scientists, legislators and society is essential to balance innovation and ethics, prioritizing well-being in the formation of families.Objetivo: O objetivo deste artigo é explorar as complexidades da reprodução assistida, examinando desafios técnicos, questões éticas, impacto psicossocial e perspectivas futuras. Busca-se fornecer uma visão abrangente do campo, promovendo a compreensão das implicações científicas, éticas e sociais associadas à reprodução assistida, enquanto destaca a importância da inovação responsável e do cuidado holístico. Metodologia: Foi realizada uma revisão sistemática de literatura abrangendo os anos de janeiro de 2010 a dezembro de 2023. O estudo teve como base e norteamento a pergunta citada no decorrer do artigo. Resultados: Este artigo visa abordar as nuances da reprodução assistida, abrangendo desafios técnicos, questões éticas, impacto psicossocial e perspectivas futuras. Busca-se oferecer uma visão completa do campo, destacando as implicações científicas, éticas e sociais, e enfatizando a importância da inovação responsável e do cuidado holístico. Conclusão: Perspectivas futuras na reprodução assistida trazem avanços científicos, como inteligência artificial e técnicas avançadas. Contudo, inovações demandam abordagem ética em áreas como edição genética. Saúde mental torna-se central, exigindo ambientes de tratamento sensíveis. Colaboração entre cientistas, legisladores e sociedade é essencial para equilibrar inovação e ética, priorizando bem-estar na formação de famílias

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

Twenty-three unsolved problems in hydrology (UPH) – a community perspective

This paper is the outcome of a community initiative to identify major unsolved scientific problems in hydrology motivated by a need for stronger harmonisation of research efforts. The procedure involved a public consultation through on-line media, followed by two workshops through which a large number of potential science questions were collated, prioritised, and synthesised. In spite of the diversity of the participants (230 scientists in total), the process revealed much about community priorities and the state of our science: a preference for continuity in research questions rather than radical departures or redirections from past and current work. Questions remain focussed on process-based understanding of hydrological variability and causality at all space and time scales. Increased attention to environmental change drives a new emphasis on understanding how change propagates across interfaces within the hydrological system and across disciplinary boundaries. In particular, the expansion of the human footprint raises a new set of questions related to human interactions with nature and water cycle feedbacks in the context of complex water management problems. We hope that this reflection and synthesis of the 23 unsolved problems in hydrology will help guide research efforts for some years to come