Optimal Design of Sustainable Reinforced Concrete Precast Hinged Frames

[EN] Sustainable development requires improvements in the use of natural resources. The main objective of the present study was to optimize the use of materials in the construction of reinforced concrete precast hinged frames. Proprietary software was developed in the Python programming language. This allowed the structure¿s calculation, verification and optimization through the application of metaheuristic techniques. The final cost is a direct representation of the use of materials. Thus, three algorithms were applied to solve the economic optimization of the frame. By applying simulated annealing, threshold accepting and old bachelor¿s acceptance algorithms, sustainable, non-traditional designs were achieved. These make optimal use of natural resources while maintaining a highly restricted final cost. In order to evaluate the environmental impact improvement, the carbon-dioxide-associated emissions were studied and compared with a reference cast-in-place reinforced concrete frame. The results showed designs with reduced upper slab and lateral wall depth and dense passive reinforcement. These were able to reduce up to 24% of the final cost of the structure as well as over 30% of the associated emissions.The authors acknowledge the financial support of Grant PID2020-117056RB-I00 funded by MCIN/AEI/10.13039/501100011033 and by "ERDF A way of making Europe"Ruiz-Vélez, A.; Alcalá-González, J.; Yepes, V. (2022). Optimal Design of Sustainable Reinforced Concrete Precast Hinged Frames. Materials. 16(1):1-23. https://doi.org/10.3390/ma1601020412316

Lattice effects and current reversal in superconducting ratchets

Competition between the vortex lattice and a lattice of asymmetric artificial defects is shown to play a crucial role in ratchet experiments in superconducting films. We present a novel and collective mechanism for current reversal based on a reconfiguration of the vortex lattice. In contrast to previous models of vortex current reversal, the mechanism is based on the global response of the vortex lattice to external forces.Comment: 12 pages, 7 figure

Optimización de marcos articulados prefabricados de hormigón armado mediante recocido simulado híbrido

[EN] Reinforced concrete precast hinged frames are commonly used in transportation infrastructure. Advances in optimization techniques lead to improvements in the traditional structural design process. These allow for minimizing factors such as the final cost of the structure. The present study developed the economic optimization of a reinforced concrete precast hinged frame. In order to do so, the hybrid metaheuristic technique of simulated annealing with a mutation operator was applied. The algorithm parameters were tuned by means of a factorial Design of Experiments. This allowed the algorithm to show excellent performance. Once tuned, the hybrid metaheuristic was applied, achieving designs with reduced final costs. Finally, a series of main characteristics are mentioned. The designs present reduced depths and considerably dense passive reinforcement designs. The results obtained position the precast structure as a particularly interesting alternative to similar cast in place structures[ES] Los marcos articulados prefabricados de hormigón armado son una estructura de uso común en las redes de carreteras. Los avances en las técnicas de optimización permiten mejorar el proceso de diseño tradicional, consiguiendo minimizar factores como el coste final de la estructura. El estudio llevó a cabo la optimización económica de un marco articulado prefabricado de hormigón armado mediante la técnica metaheurística híbrida de recocido simulado con operador de mutación. Los parámetros del algoritmo fueron calibrados mediante un diseño de experimentos factorial, consiguiendo que el algoritmo tuviera un muy buen rendimiento. Tras su calibración, la metaheurística híbrida fue aplicada, consiguiendo diseños con costes finales reducidos. Finalmente, se mencionan una serie de características principales de los marcos óptimos, pudiendo destacar diseños esbeltos con densidades de armado elevadas. Los resultados sitúan la tipología estructural considerada como una alternativa especialmente interesante frente a las estructuras ejecutadas in situ.Los autores agradecen la financiación del proyecto PID2020-117056RB-I00 financiado por el Ministerio de Ciencia e Innovación MCIN / AEI / 10.13039 / 501100011033 y por "FEDER Una manera de hacer Europa".Ruiz-Vélez, A.; Alcalá-González, J.; Kripka, M.; Yepes, V. (2022). Optimización de marcos articulados prefabricados de hormigón armado mediante recocido simulado híbrido. Revista CIATEC-UPF. 14(3):41-55. https://doi.org/10.5335/ciatec.v14i3.14079415514

Enhancement of synchronized vortex lattice motion in hybrid magnetic/amorphous superconducting nanostructures

Superconducting a-Mo_(3)Si and Nb films have been grown on arrays of Ni nanodots. We have studied the vortex lattice dynamics close to critical temperatures. Different vortex lattice configurations are obtained with the same array unit cell. These different vortex lattices occur at matching conditions between the vortex lattice and the array unit cell. The interplay between the random intrinsic pinning of the superconducting films and the periodic pinning of the array govern the vortex lattice configurations. Different vortex lattice configurations and enhancement of synchronized vortex lattice motion are obtained by increasing the periodic pinning strength and decreasing the random pinning strength

Topologically protected superconducting ratchet effect generated by spin-ice nanomagnets

We have designed, fabricated and tested a robust superconducting ratchet device based on topologically frustrated spin ice nanomagnets. The device is made of a magnetic Co honeycomb array embedded in a superconducting Nb film. This device is based on three simple mechanisms: (i) the topology of the Co honeycomb array frustrates in-plane magnetic configurations in the array yielding a distribution of magnetic charges which can be ordered or disordered with in-plane magnetic fields, following spin ice rules; (ii) the local vertex magnetization, which consists of a magnetic half vortex with two charged magnetic Neel walls; (iii) the interaction between superconducting vortices and the asymmetric potentials provided by the Neel walls. The combination of these elements leads to a superconducting ratchet effect. Thus, superconducting vortices driven by alternating forces and moving on magnetic half vortices generate a unidirectional net vortex flow. This ratchet effect is independent of the distribution of magnetic charges in the array

Síndrome urémico hemolítico: eco-epidemiología del enemigo que afecta la seguridad alimentaria

Escherichia coli verocitotoxigénico (VTEC) es un patógeno emergente asociado a casos de diarrea, colitis hemorrágica y síndrome urémico hemolítico (SUH), del cual Argentina presenta el registro más alto de casos a nivel mundial. No existe tratamiento específico para el SUH, por lo que son fundamentales las estrategias de control y prevención. Los estudios se han centralizado en cepas del serotipo O157:H7, pero las infecciones asociadas a VTEC no-O157 tienen creciente importancia y representan nuevos desafíos para el diagnóstico y el control de VTEC. En este trabajo se evaluó el rol de distintas especies animales, medio ambiente y alimentos en la epidemiología de VTEC, se caracterizó la variabilidad genética y la virulencia de las cepas, y se estudiaron medidas de control. Las metodologías comprenden técnicas microbiológicas y de biología molecular. Los resultados confirman la amplia distribución de las cepas VTEC, demuestran su gran diversidad genética y la presencia de factores de virulencia asociados con enfermedad en el hombre. Las cepas estudiadas mostraron alta capacidad para sobrevivir en el ambiente. La exhaustiva caracterización de las cepas resalta el alto riesgo para la salud pública que representan.Trabajo presentado por el Centro de Investigación Veterinaria de Tandil (CIVETAN)

Ocean Circulation over Formigas and Ormonde Seamounts

Seamounts constitute an obstacle to the free ocean flow, modifying the patter of circulation. As a result of these alterations, a variety of hydrodynamical processes and phenomena may take place in seamounts, among others, Taylor columns/caps. These oceanographic effects may turn seamounts into very productive ecosystems with high biodiversity. Under these conditions seamounts provide a particularly good environment for the settle of some organisms, acting as stepping stones and contributing to its dispersal. In this study, we verify if these oceanographic effects explain the presence of cold-water corals of Mediterranean origin in the Atlantic. To achieve this, three seamounts in the path of the Mediterranean Outflow Water (MOW) through the Eastern North Atlantic were selected: the Gazul mud volcano, and the Ormonde and Formigas seamounts. In order to determine the hydrographic and dynamical conditions in each one of the three locations, CTD, LADPC and biochemical observations were carried out. Taylor columns were not observed in any of the three sampled areas. Although we found suggestions of upwelling/downwelling systems, their effect was barely noticed in the circulation pattern. The oceanographic processes in those areas are more influenced by the vertical distribution of water masses, which determine the stability of the water column. Moreover, the high values of the Brunt-Väisälä frequency around the MOW halocline can lead to the formation of internal waves. These perturbations in the water column can enhance the vertical mixing, producing suspension, which, in turn, could affect the vertical distribution of cold-water corals

Effects of an exercise program on hepatic metabolism, hepatic fat, and cardiovascular health in overweight/obese adolescents from Bogotá, Colombia (the HEPAFIT study): study protocol for a randomized controlled trial

Background: A considerable proportion of contemporary youth have a high risk of obesity-related disorders such as cardiovascular disease, metabolic syndrome, or non-alcoholic fatty liver disease (NAFLD). Although there is consistent evidence for the positive effects of physical activity on several health aspects, most adolescents in Colombia are sedentary. It is, therefore, important to implement strategies that generate changes in lifestyle. The HEPAFIT study aims to examine whether a 6-month exercise program has benefits for hepatic fat content and cardiovascular health outcomes among overweight/obese adolescents from Bogotá, Colombia. Methods/design: Altogether, 100 hundred overweight/obese, sedentary adolescents (aged 11–17 years) attending two public schools in Bogotá, Colombia, will be included in a parallel-group randomized controlled trial. Adolescents will be randomly assigned to an intervention group following one of four curricula: (1) the standard physical education curriculum (60 min per week of physical activity, n = 25) at low-to-moderate intensity; (2) a high-intensity physical education curriculum (HIPE, n = 25), consisting of endurance and resistance games and non-competitive activities, such as running, gymkhanas, lifting, pushing, wrestling, or hauling, for 60-min sessions, three times per week, with an energy expenditure goal of 300 to 500 kcal/session at 75–85% maximum heart rate (HRmax); (3) a low-to-moderate intensity physical education curriculum (LIPE, n = 25) consisting of endurance and resistance games and non-competitive activities (e.g., chasing, sprinting, dribbling, or hopping) for 60-min sessions, three times per week with an energy expenditure goal of 300 kcal/session at 55–75% HRmax; and (4) a combined HIPE and LIPE curriculum (n = 25). The HIPE, LIPE, and combined interventions were performed in addition to the standard physical education curriculum. The primary outcome for effectiveness is liver fat content, as measured by the controlled attenuation parameter 1 week after the end of the intervention program. Discussion: The translational focus may be suitable for collecting new information in a school setting on the possible effects of physical activity interventions to reduce liver fat content and to improve metabolic profiles and the cardiometabolic health of overweight/obese adolescents. This may lead to the more efficient use of school physical education resources.The HEPAFIT study was carried out with the financial support of Instituto Colombiano para el Desarrollo de la Ciencia y la Tecnología “Francisco José de Caldas” COLCIENCIAS (code 59700 and no 122277757900). Katherine González-Ruíz receive a scholarship from Universidad del Rosario, Colombia, Escuela de Medicina y Ciencias de la Salud, to do a Doctorate. This article presents independent research commissioned by COLCIENCIAS under its Program Grants for Applied Research funding scheme (Convocatoria 777–2017)