Thermomechanical Modeling of Welding and Galvanizing a Steel Beam Connection Detail to Examine Susceptibility to Cracking

Hot-dip galvanizing is the process of submerging steel elements into molten zinc to form a metallurgically bonded zinc coating that serves as corrosion protection for the steel substrate. Used with great success on an industrial scale for many decades, hot-dip galvanizing is a ubiquitous process. On occasion, cracks in steel members develop during galvanizing. While such cracking remains a poorly understood phenomenon, previous research has attributed the formation of cracks to the combined effects of residual strains introduced by welding and temperature-induced deformations caused by the hot-dip galvanizing process. This article presents thermomechanical analyses of a structural steel beam with a welded double-angle connection detail where cracking occurred during hot-dip galvanizing. Three-dimensional finite element models of the beam and connection detail were analyzed using the finite element analysis software Abaqus (Dassault Systèmes, Vélizy-Villacoublay, France). The welding process was simulated using the Abaqus Welding Interface, maintaining the welding sequence of the connection. After welding, the entire beam was subjected to a temperature field that was specified through a user subroutine in Abaqus, simulating the hot-dip galvanizing process. The temperature field had a bath temperature of 450°C and a thermal cycle that included dipping, dwell time, and removal from the bath. Material properties used in the simulation were nonlinear and temperature dependent. The parameters of the study were the welding sequences, heat input during welding, and the depth of the double-angle connection. It was observed that strain demands due to welding and hot-dip galvanizing were high magnitude at the cracked location in the beam. The relative significance of strain demands due to welding and of hot-dip galvanizing on the propensity for the beam to develop cracks are discussed

Hacia la evaluación del desempeño de un modelo de integración de agentes inteligentes & WSN a través de métricas

Las Redes de Sensores Inalámbricas o WSN (por su acrónimo en inglés Wireless Sensor Networks), en general, son redes inalámbricas que se componen de centenares o miles de dispositivos autónomos y compactos llamados nodos sensores. Las WSN son un área emergente de los sistemas embebidos que involucran aplicaciones de gran escala, incluyendo monitoreo, conservación ambiental y control industrial. Sin embargo, aún existen muchas limitaciones en éstas, tales como el consumo de energía, la organización de los nodos en la red, la reprogramación de la red de sensores, la confiabilidad en la transmisión de los datos, la optimización de recursos (memoria y procesamiento), etc., que requieren de investigación por parte de la comunidad científica. Investigaciones actuales incluyen el uso de técnicas de Inteligencia Artificial Distribuida (IAD), específicamente de agentes inteligentes, para hacer frente a los desafíos y limitaciones que éstas traen consigo. De esta forma, se requiere evaluar el desempeño de este modelo integrado (IAD + WSN) a través del uso de métricas. El propósito de este artículo es plantear las principales métricas que serán consideradas para evaluar el desempeño de la integración de agentes inteligentes y WSN

Towards the evaluation of the performance of an integration model of intelligent agents & WSN through metrics

Las Redes de Sensores Inalámbricas o WSN (por su acrónimo en inglés Wireless Sensor Networks), en general, son redes inalámbricas que se componen de centenares o miles de dispositivos autónomos y compactos llamados nodos sensores. Las WSN son un área emergente de los sistemas embebidos que involucran aplicaciones de gran escala, incluyendo monitoreo, conservación ambiental y control industrial. Sin embargo, aún existen muchas limitaciones en éstas, tales como el consumo de energía, la organización de los nodos en la red, la reprogramación de la red de sensores, la confiabilidad en la transmisión de los datos, la optimización de recursos (memoria y procesamiento), etc., que requieren de investigación por parte de la comunidad científica. Investigaciones actuales incluyen el uso de técnicas de Inteligencia Artificial Distribuida (IAD), específicamente de agentes inteligentes, para hacer frente a los desafíos y limitaciones que éstas traen consigo. De esta forma, se requiere evaluar el desempeño de este modelo integrado (IAD + WSN) a través del uso de métricas. El propósito de este artículo es plantear las principales métricas que serán consideradas para evaluar el desempeño de la integración de agentes inteligentes y WSN.Wireless Sensor Networks or WSN (by its acronym in English Wireless Sensor Networks), in general, are wireless networks that are made up of hundreds or thousands of compact, self-contained devices called sensor nodes. WSNs are an emerging area of systems embedded systems that involve large-scale applications, including monitoring, environmental conservation and industrial control. However, there are still many limitations in these, such as energy consumption, the organization of the nodes in the network, the reprogramming of the sensor network, the reliability in the data transmission, optimization of resources (memory and processing), etc., that require investigation by the community scientific. Current research includes the use of Intelligence techniques Distributed Artificial Intelligence (IAD), specifically of intelligent agents, to face the challenges and limitations that they bring with them. This form, it is necessary to evaluate the performance of this integrated model (IAD + WSN) through the use of metrics. The purpose of this article is to raise the main metrics that will be considered to evaluate the performance of the integration of intelligent agents and WSN

Gestión de resultado de investigación en Instituciones de Educación Superior

"El presente libro se deriva del proyecto de investigación «La introducción de resultados de las investigaciones científicas "" tecnológicas en Instituciones de Educación Superior»: un análisis explicativo de sus alcances en la solución de problemas sociales, empresariales y académicos en tres instituciones de la ciudad de Medellín: Instituto Tecnológico Metropolitano, Politécnico Colombiano Jaime Isaza Cadavid y la Facultad de Ciencias Humanas y Sociales de la Universidad de Antioquia. Se propone como objetivo dar cuenta de los componentes necesarios a tener presente en la configuración de un modelo para la gestión de los resultados de la investigación en Ciencia, Tecnología e Innovación en las Instituciones de Educación Superior. Con este estudio se espera lograr una contribución a la gestión del conocimiento que dé cuenta de las posibles estrategias, para avanzar de la producción de la ciencia, la tecnología y la innovación, hacia la introducción, generalización y validación de sus resultados en los diversos contextos, donde se hacen necesarios para lograr metas coherentes con los procesos de construcción de una sociedad del conocimiento.""""This book is derived from the research project """"The introduction of results from scientific-technological research in Higher Education Institutions"""": a comprehensive analysis of their scope in the solution of social, business and academic problems in three institutions from Medellín: Instituto Tecnológico Metropolitano, Politécnico Colombiano Jaime Isaza Cadavid and the Faculty of Human and Social Sciences of the Universidad de Antioquia. The book aims at presenting the necessary components that must be present in the configuration of a model for the management of research results in Science, Technology and Innovation in Higher Education Institutions. This study is expected to be a contribution to knowledge management that presents the potential strategies for progress in the production of science, technology and innovation, aiming at the introduction, generalization and validation of the results in the various contexts in which they are needed to achieve goals consistent with the process of building a knowledge society.""

Un-explained visual loss following silicone oil removal: Results of the Pan American Collaborative Retina Study (PACORES) Group

Purpose: To report the incidence and clinical features of patients that experienced un-explained visual loss following silicone oil (SO) removal. Methods: Multicenter retrospective study of patients that underwent SO removal during 2000-2012. Visual loss of ≥2 lines was considered significant. Results: A total of 324 eyes of 324 patients underwent SO removal during the study period. Forty two (13%) eyes suffered a significant visual loss following SO removal. Twenty three (7.1%) of these eyes lost vision secondary to known causes. In the remaining 19 (5.9%) eyes, the loss of vision was not explained by any other pathology. Eleven of these 19 patients (57.9%) were male. The mean age of this group was 49.2 ± 16.4 years. Eyes that had an un-explained visual loss had a mean IOP while the eye was filled with SO of 19.6 ± 6.9 mm Hg. The length of time that the eye was filled with SO was 14.8 ± 4.4 months. In comparison, eyes that did not experience visual loss had a mean IOP of 14 ± 7.3 mm Hg (p < 0.0002) and a mean tamponade duration of 9.3 ± 10.9 months (p < 0.0001). Conclusions: An un-explained visual loss after SO removal was observed in 5.9% of eyes. Factors associated with this phenomenon included a higher IOP and longer SO tamponade duration. © The Author(s) 2017

Longitudinal relationship of liver injury with inflammation biomarkers in COVID-19 hospitalized patients using a joint modeling approach

The mechanisms underlying liver disease in patients with COVID-19 are not entirely known. The aim is to investigate, by means of novel statistical techniques, the changes over time in the relationship between inflammation markers and liver damage markers in relation to survival in COVID-19. The study included 221 consecutive patients admitted to the hospital during the first COVID-19 wave in Spain. Generalized additive mixed models were used to investigate the influence of time and inflammation markers on liver damage markers in relation to survival. Joint modeling regression was used to evaluate the temporal correlations between inflammation markers (serum C-reactive protein [CRP], interleukin-6, plasma D-dimer, and blood lymphocyte count) and liver damage markers, after adjusting for age, sex, and therapy. The patients who died showed a significant elevation in serum aspartate transaminase (AST) and alkaline phosphatase levels over time. Conversely, a decrease in serum AST levels was observed in the survivors, who showed a negative correlation between inflammation markers and liver damage markers (CRP with serum AST, alanine transaminase [ALT], and gamma-glutamyl transferase [GGT]; and D-dimer with AST and ALT) after a week of hospitalization. Conversely, most correlations were positive in the patients who died, except lymphocyte count, which was negatively correlated with AST, GGT, and alkaline phosphatase. These correlations were attenuated with age. The patients who died during COVID-19 infection displayed a significant elevation of liver damage markers, which is correlated with inflammation markers over time. These results are consistent with the role of systemic inflammation in liver damage during COVID-19S

The persistent shadow of the supermassive black hole of M 87

In April 2019, the Event Horizon Telescope (EHT) Collaboration reported the first-ever event-horizon-scale images of a black hole, resolving the central compact radio source in the giant elliptical galaxy M 87. These images reveal a ring with a southerly brightness distribution and a diameter of ∼42 μas, consistent with the predicted size and shape of a shadow produced by the gravitationally lensed emission around a supermassive black hole. These results were obtained as part of the April 2017 EHT observation campaign, using a global very long baseline interferometric radio array operating at a wavelength of 1.3 mm. Here, we present results based on the second EHT observing campaign, taking place in April 2018 with an improved array, wider frequency coverage, and increased bandwidth. In particular, the additional baselines provided by the Greenland telescope improved the coverage of the array. Multiyear EHT observations provide independent snapshots of the horizon-scale emission, allowing us to confirm the persistence, size, and shape of the black hole shadow, and constrain the intrinsic structural variability of the accretion flow. We have confirmed the presence of an asymmetric ring structure, brighter in the southwest, with a median diameter of 43.3−3.1+1.5 μas. The diameter of the 2018 ring is remarkably consistent with the diameter obtained from the previous 2017 observations. On the other hand, the position angle of the brightness asymmetry in 2018 is shifted by about 30° relative to 2017. The perennial persistence of the ring and its diameter robustly support the interpretation that the ring is formed by lensed emission surrounding a Kerr black hole with a mass ∼6.5 × 109 M⊙. The significant change in the ring brightness asymmetry implies a spin axis that is more consistent with the position angle of the large-scale jet

Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030