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Manufacturing maraging steel components using laser-based powder bed fusion (LPBF) presents an attractive proposition for industries due to the material's combination of mechanical properties such as hardness, wear resistance, toughness and the capability to produce parts with complex geometries and high precision. Despite these advantages, the LPBF process induces defects such as distortion and residual stress associated with the complex thermal cycles, compromising final part quality. Numerical simulations have been developed to predict these defects. However, LPBF simulations remain challenging due to the complexity of the process and the substantial computational resources required. For maraging steel, for example, the occurrence of phase transformation promotes compressive stress that interferes in results and makes simulations inaccurate. This research aims to simulate a geometry with a circular inner channel and investigate distortion, volume fraction of martensite and equivalent stress results. Modeling was performed by varying phase transformation rate parameters to assess the impact of transformations on simulation outcomes. Results showed minimal impact of these parameters on distortions and equivalent stress. Equivalent stress results were compared with literature findings, while distortion results were validated against experimental data to validate the accuracy of the model.

Introduction: The novel coronavirus, dubbed SARS-CoV-2, which causes the COVID-19 disease, was detected on December 31, 2019, in Wuhan, China. Objective: To perform a systematic review with a meta-analysis about the prevalence of headache and myalgia in patients with SARS-CoV-2. Methods: High-sensitivity research was conducted on the main platforms (Medline by PubMed, Embase (Elsevier), and Cochrane Library). The entire versions of the manuscripts were analyzed by three independent researchers, and only observational studies describing the symptoms of the selected sample were included. Results: 1,782 studies were identified, which were submitted to exclusion criteria, remaining only 62 manuscripts to do qualitative synthesis and metanalysis. Of the 28,412 patients diagnosed with SARS-CoV-2, 12% (95% CI 9% - 16%) presented headache and 19% (95% CI 14% - 24%) presented myalgia, both with statistical significance and high heterogeneity (I2=97.0%, p

Este artículo reseña: Luis Efrén RÍOS VEGA, Irene SPIGNO (dirs.), Fernando Gustavo RUZ DUEÑAS (coord.), Los derechos humanos en los tiempos de la pandemia Covid-19, Tirant lo Blanch, México, 2022, 262 pp.

Superduplex stainless steels (SDSS) are known for their combination of good mechanical properties and excellent corrosion resistance, enabled by the microstructural balance between austenite and ferrite and an amount of alloying elements. Their application in welded components is, however, limited by the possibility of the precipitation of intermetallic phases and microstructural misbalance, which might hinder their properties, especially in the heat-affected zone (HAZ). This work introduces a methodology that relies simultaneously on physical and numerical simulations to study the HAZ in a UNS S32750 SDSS. Dimensions of the fusion zone and thermal cycles were calibrated for a numerical model using preliminary welding trials. Numerically simulated cycles for each heat input (HI) were physically reproduced in a Gleeble® simulator, and the heat-treated samples were characterized and compared with real specimens welded using the same parameters. Thermal curves resulting from the numerical simulations were successfully replicated by the Gleeble®, indicating adequate application of the desired HI. The hardness and microstructural results from simulated and welded specimens were also found to be quite similar. Therefore, the proposed methodology showed itself adequate not only for the study of duplex stainless steels, but also of materials with similar thermal and mechanical properties, including the extrapolation of welding parameters.

En el contexto de la globalización, y tomando en consideración las múltiples tensiones que dicho escenario impone sobre el concepto de ciudadanía, es necesario cuestionar aquellos elementos que bajo una lectura clásica de la misma, impiden su ejercicio fuera de los márgenes del Estado. Por ello, en este artículo se analizan elementos como el patriotismo y la nacionalidad, así como las repercusiones que tiene la inmigración en dicho concepto, con el fin de hacer una propuesta más dinámica de la ciudadanía, acorde con la realidad contemporánea.

El concepto de ciudadanía cosmopolita ha estado presente en el pensamiento filosófico desde la Ilustración. En la filosofía política contemporánea este concepto ha merecido la atención de algunos autores, aunque no todas sus propuestas han tenido el mismo éxito. En este trabajo se analizan algunas de las ideas que sobre la ciudadanía cosmopolita expuso John Rawls en su trabajo “El derecho de gentes”, y algunas críticas que pueden hacerse a esa propuesta.

Immobility in the bed of pediatric patients in intensive care units increases the risk of morbidities such as pneumonia, with consequences for autonomic function. Physiotherapy based on physical exercise is part of the rehabilitation process and can modify autonomic function. To compare the effects of two physical therapy protocols, one conventional and the other based on physical exercise, on heart rate variability, length of stay and invasive mechanical ventilation in children with ventilator-associated pneumonia. This is a randomized clinical trial, the volunteers were divided into a control group (submitted to a physiotherapy protocol with only breathing exercises and passive mobilization) and an experimental group (submitted to a physiotherapy protocol based on physical exercise). Patients aged 1 to 8 years, on invasive mechanical ventilation, with pneumonia were included. The rehabilitation protocol took place for 4 consecutive days. The collection of heart rate variability occurred in the pre-protocol period, on the 2nd day, 1 day after the end of the protocol. 25 patients completed the study. There was a reduction in the time of invasive mechanical ventilation in the experimental group (p = 0.01). There was an improvement in the heart rate variability of the experimental group in all indices (p < 0.01). The post-protocol analysis of the groups showed significant values in all variables (p < 0.05). Exercise-based physical therapy protocol improved autonomic heart rate modulation and reduced IMV time in children with ventilator-associated pneumonia.

This work provides a comprehensive evaluation of the energy transition scenarios of four countries Brazil, Germany, France, and the UK in the context of climate change and the urgent need for decarbonisation and their efforts to achieve NetZero goals by 2030. The study adopts bibliometric analysis as a technical procedure to identify energy transition policies, research groups, and institutions, actions of private companies, and new perspectives and trends for future studies about NetZero. The analysis highlights the emergence of new technologies such as bioenergy, hydrogen-based systems, and renewable energy storage solutions, which are essential for achieving NetZero goals. It emphasizes the need to move beyond using fossil fuels more efficiently and instead, to adopt innovative approaches to decarbonise industries and transportation. The study highlights the emergence of new technologies such as hydrogen-based systems, renewable energy storage solutions, and advanced carbon capture and utilization methods, which have the potential to accelerate the energy transition. The circular economy is also emerging as a promising avenue for reducing waste and conserving resources. The research identifies block chain technology as a potential tool for facilitating carbon offset trading, while artificial intelligence can be used to optimize energy consumption. Collaboration between governments, research institutions, and private companies is essential for driving progress in the field and achieving NetZero goals. Overall, this research provides valuable insights and a starting point for further studies on NetZero and decarbonisation.

Boron-manganese steel 22MnB5 is extensively used in structural automotive components. Knowledge about its microstructural evolution during hot stamping and resistance spot welding (RSW) is extremely relevant to guarantee compliance with application requirements. Particularly, corrosion properties are critical to the application of uncoated sheet steels. However, microstructural studies are usually simplified to top-hat geometries, which might not be fully representative of the complex thermomechanical cycles locally faced by a real component. Therefore, the present work brings an extensive characterization of a hot-stamped 22MnB5 automotive B-pillar in terms of microstructure, hardness and corrosion resistance, which were correlated with a reverse engineering of the process using numerical simulation. Physical simulations of the subcritical heat affected zone (SCHAZ) of RSW were done to assess the influence of microstructure on martensite tempering. Results showed that the component undergoes a complex strain distribution along its body during hot stamping. Most heavily strained regions presented higher amounts of ferrite, leading to poorer corrosion resistance, since ferrite behaves as an anode. Physical simulations of the SCHAZ showed that the softening degree due to martensite tempering is solely affected by peak temperature, while other microstructural features appear to exert negligible or no influence.

The excellent casting behavior and mechanical and corrosion properties of aluminum-silicon (Al-Si)-based alloys make them ideal for the manufacture of lightweight components with complex geometries. However, these properties depend directly on their microstructure, which, in its turn, is strongly affected by the composition of the alloy, among other factors. Several elements can be added to the material aiming to promote microstructural changes, e.g., grain refinement, optimization of phase morphology and distribution, and precipitation strengthening. Efforts are continuously put into such enhancements of cast Al alloys since they lead to quality improvements that allow for weight reduction and safety increase. Considering the technological relevance of the subject, this paper provides an overview of the research focused on the addition of alloying elements to these alloys, with a greater focus on Al-Si-based systems and the comprehension of the effects of these additions on their microstructure and properties.

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Although several clinical manifestations of persistent long coronavirus disease (COVID-19) have been documented, their effects on the cardiovascular and autonomic nervous system over the long term remain unclear. Thus, we examined the presence of alterations in cardiac autonomic functioning in individuals with long-term manifestations. The study was conducted from October 2020 to May 2021, and an autonomic assessment was performed to collect heart rate data for the heart rate variability (HRV) analysis. The study participants were divided into the long COVID clinical group, the intragroup, which included patients who were hospitalized, and those who were not hospitalized and were symptomatic for different periods (≤3, >3, ≤6, and >6 months), with and without dyspnoea. The control group, the intergroup, comprised of COVID-free individuals. Our results demonstrated that the long COVID clinical group showed reduced HRV compared with the COVID-19-uninfected control group. Patients aged 23–59 years developed COVID symptoms within 30 days after infection, whose diagnosis was confirmed by serologic or reverse-transcription polymerase chain reaction (swab) tests, were included in the study. A total of 155 patients with long COVID [95 women (61.29%), mean age 43.88 ± 10.88 years and 60 men (38.71%), mean age 43.93 ± 10.11 years] and 94 controls [61 women (64.89%), mean age 40.83 ± 6.31 and 33 men (35.11%), mean age 40.69 ± 6.35 years] were included. The intragroup and intergroup comparisons revealed a reduction in global HRV, increased sympathetic modulation influence, and a decrease in parasympathetic modulation in long COVID. The intragroup showed normal sympathovagal balance, while the intergroup showed reduced sympathovagal balance. Our findings indicate that long COVID leads to sympathetic excitation influence and parasympathetic reduction. The excitation can increase the heart rate and blood pressure and predispose to cardiovascular complications. Short-term HRV analysis showed good reproducibility to verify the cardiac autonomic involvement.

This study presents a comparative life cycle assessment (LCA) of two manufacturing scenarios for a camera housing: Powder Bed Fusion (PBF) using polyamide 12 (PA-12) and Computer Numeric Control (CNC) machining using aluminum, for a cradle-to-gate boundary. The selected impact categories were cumulative energy demand (CED) and global warming potential (GWP). The key findings indicate that the PA-12 PBF part outperformed the aluminum CNC machining one in terms of environmental and energy performance, showing a significant reduction of approximately 90% in equivalent carbon emissions and 84% in cumulative energy demand. Sensitivity analyses revealed that the PBF process was highly sensitive to changes in the proportion of virgin/recycled material for the printing process, variations in the life cycle inventory (LCI) data sources for PA-12 powder production, and changes in the transportation system for imported materials, as is the case for the main input in the process (PA-12 powder). Sensitivity analysis also showed less impact for the PBF camera housing even considering a lifespan of one-fifth that of the aluminum for the impact categories considered. However, it should be noted that this analysis did not include considerations for the usage and end-of-life phases, which may have significant contributions to the overall environmental impact. [ABSTRACT FROM AUTHOR]

The use of ultra-high-strength steels (UHSS) has been growing in recent years, mainly in the automotive industry. Since these steels have high strength and hardness, more applied stresses are required to deform them, probably also impacting friction behaviour. In this article, a variation in the process parameters commonly observed in sheet-metal forming, such as contact pressure, sliding speed, lubrication and working temperature was performed. The material used was TRIP1000. These process parameters were varied, aiming to investigate the friction-coefficient behaviour; however, it was observed that there were no significant variations, indicating that the steel hardness may have contributed to this. Another finding is that, even if the lubricant did not change the average value of the friction coefficient, it contributed to a more stable process, favouring the absence of premature wear of the tools.