Structure, Configuration And Sizing Of Ni Nanoparticles Generated By Ultrafast Laser Ablation In Different Media

In recent years, nickel nanoparticles (NPs) have increased scientific interest because of their extensive prospects in catalysts, information storage, large-scale batteries and biomedicine. Several works on Ni NPs generation by laser ablation have appeared in the literature in the last years, using different pulsed laser regimes and different media have been published recently. In this work we analyze the characteristics of species, structure (bare core or core-shell), configuration and size distribution of NPs generated by fs pulse laser ablation over a Ni solid target in n-heptane and water. We explore the presence of NiO-Ni core-shell and hollow Ni (or air-Ni) NPs in the colloids obtained. These were experimentally characterized using AFM and TEM microscopy, as well as Optical Extinction Spectroscopy (OES). Extinction spectra were modeled using Mie theory through an appropriate modification of the complex experimental dielectric function, taking into account a size-dependent corrective term for each free and bound electron contribution. Experimental UV-visible-NIR spectra were reproduced considering a size distribution of bare core, hollow and core-shell structures NPs. In both media, Ni NPs shape and size distribution agrees with that derived from TEM and AFM analysis.954

Palatini f(R)f(R) gravity tests in the weak field limit: Solar System, seismology and galaxies

Palatini $f(R)$ gravity is probably the simplest extension of general relativity (GR) and the simplest realization of a metric-affine theory. It has the same number of degrees of freedom as GR and, in vacuum, it is straightforwardly mapped into GR with a cosmological constant. The mapping between GR and Palatini $f(R)$ inside matter is possible but at the expense of reinterpreting the meaning of the matter fields. The physical meaning and consequences of such mapping will depend on the physical context. Here we consider three such cases within the weak field limit: Solar System dynamics, planetary internal dynamics (seismology), and galaxies. After revising our previous results on the Solar System and Earth's seismology, we consider here the possibility of $f(R)$ Palatini as a dark matter candidate. For any $f(R)$ that admits a polynomial approximation in the weak field limit, we show here, using SPARC data and a recent method that we proposed, that the theory cannot be used to replace dark matter in galaxies. We also show that the same result applies to the Eddington-inspired Born-Infeld gravity. Differently from the metric $f(R)$ case, the rotation curve data are sufficient for this conclusion. This result does not exclude a combination of modified gravity and dark matter.Comment: 20 pages, 2 figures. Submitted as a research article related to the conference Metric-Affine Frameworks for Gravity 202

Static Model of Cement Rotary Kiln

En este trabajo, se presenta un modelo estático de un horno rotatorio de cemento. El modelo del sistema se obtiene a través de series de polinomio. El modelo propuesto se verifica con datos reales de la planta, donde se obtuvieron resultados óptimos. Los resultados esperados son medidos con respecto a la producción de Clinker. El consumo de combustible se mide en relación con el consumo calorífico. Los resultados esperados del enfoque es el incremento de los beneficios de la empresa a través de la reducción en el consumo de combustible.In this paper, a static model of cement rotary kilns is proposed. The system model is obtained through polynomial series. The proposed model is contrasted with data of a real plant, where optimal results are obtained. Expected results are measured with respect to the clinker production and the combustible consumption is measured in relation with the consumption calorific. The expected result of the approach is the increase of the profitability of the factory through the decrease of the consumption of the combustible

Sistema multiobjetivo de soporte a decisiones para planificación de programación de operaciones

This research shows the design and construction of a multi objective optimization support system for decision making, DSS-SCHEDULER, in order to effectively perform naval shipbuilding operations, by managing to have a rational usage, under a limited capacity, of the installed capacity. The system creates the operational plan for the scheduling of operations as well as the allocation of all the resources related to the processes carried out at the plant, and, taking into account all the restrictions this type of service entails, generate a set of optimal solutions in order to comply with the objective functions as planned, such as costs and the promise for delivery dates to support the decision making process in scheduling Cotecmar’s industrial operations.La presente investigación muestra el diseño y construcción de un sistema de optimización Multiobjetivo de soporte a toma de decisiones, DSS-SCHEDULER, para realizar de manera efectiva la actividad de programación de operaciones en planta de astilleros navales, logrando una utilización racional, bajo capacidad finita, de la capacidad instalada, el cual realiza la creación de la planificación operativa de programación de operaciones y la asignación de todos los recursos asociados a los procesos que se realizan en la planta, y teniendo en cuenta todas las restricciones que conlleva estos servicios, generar un conjunto de soluciones óptimas cumpliendo con las funciones objetivo propuestas, como costos y promesa de fechas de entrega para apoyar la toma de decisiones de la programación de las operaciones industriales de Cotecmar

Rol de la función mitocondrial en el corazón y sus implicaciones en disfunciones cardíacas

In this review article, we examined the role of mitochondria in the good functioning of the heart, and in the generation of various cardiac conditions, which are characterized by low energy production by the mitochondria and therefore, there is an increase in the loss of cardiomyocytes that leads to malfunction of the heart. It has been determined that certain mitochondrial dysfunctions associated with cardiac disorders are related to alterations of the oxidative phosphorylation system, as well as to the reduction of certain structural components such as cardiolipin and the formation of supercomplexes. It is estimated that about 2.3% of the Colombian population may present prevalence to heart failure. The objective of the present review is to present the investigative advances related to cardiac diseases caused by mitochondrial dysfunction, as well the identification of different investigations directed at the creation of treatment alternatives for these pathologies, all in order to contribute to the construction of lines of work that take the mitochondria as a therapeutic target.En este artículo de revisión, examinamos el papel de la mitocondria en el buen funcionamiento del corazón, y en la generación de diversas afecciones cardíacas, las cuales están caracterizadas por una baja producción de energía por parte de las mitocondrias y, por ende, hay un aumento en la pérdida de cardiomiocitos que conlleva al mal funcionamiento del corazón. Se ha determinado, que ciertas disfunciones mitocondriales asociadas a trastornos cardíacos se relacionan con alteraciones del sistema de fosforilación oxidativa, así como, con la disminución de ciertos componentes estructurales como la cardiolipina y la formación de supercomplejos. Se estima que cerca del 2.3% de la población colombiana puede presentar una prevalencia a la falla cardíaca. La presente revisión tiene como objetivo dar a conocer los avances investigativos relacionados con enfermedades cardíacas ocasionadas por disfunción mitocondrial, así como, la identificación de diferentes investigaciones dirigidas en la creación de alternativas de tratamiento para dichas patologías, todo esto con el fin de contribuir a la construcción de líneas de trabajo que tomen a la mitocondria como blanco terapéutico

FMECA and FTA analysis applied to the manufacturing process of pulsating heat pipes

Pulsating heat pipes (PHPs) offer significant advantages for the thermal control of electronic components due to their simple manufacturing and high heat transfer rates. The reliability of PHPs has traditionally been assessed through long-life testing, but detailed reliability analyses from an equipment perspective are limited. The study of PHP reliability is essential due to its application and operational conditions. For instance, in aerospace applications these devices operate under severe conditions, and maintenance or replacement is impossible during operation, making them critical components in system functionality. The reliability analysis of PHPs focuses on the manufacturing process, considering future operating conditions. Although preliminary PHP testing will be conducted on Earth, laboratory conditions are less stringent due to the difficulty of replicating launch acceleration and space conditions for long-term testing under microgravity. This study presents an FMECA (Failure Modes, Effects, and Criticality Analysis) of the pulsating heat pipe manufacturing process, breaking down the production of each component. The results indicate that the most critical point is concentrated in the assembly of these components, leading to a higher incidence of welding failures. It recommends further work to improve welding and analyze mechanical stresses within the heat pipe

A multi-objective approach based on soft computing techniques for production scheduling in Corrugator manufacturing plants

AbstractThe corrugator scheduling problem is a difficult problem due to a wide varietyof parameters and optimisation objectives that have to be accounted for andthe relationships among them. Majority of solution techniques proposed so faronly deal with minimizing either, the trim waste or pattern changes, this paperproposes a multi-objective evolutionary algorithm to optimize the WPL objective(weighted planning level) and the cost objectives. Computational experimentswere conducted and results were compared against the current shop schedulingmethod used at a real-life corrugator manufacturing facility. A series of experimentswere also conducted to determine the evolutionary algorithm parameters. Theimprovement on performance metrics encourages us to actually implement thealgorithm at the factory.The corrugator scheduling problem is a difficult problem due to a wide varietyof parameters and optimisation objectives that have to be accounted for andthe relationships among them. Majority of solution techniques proposed so faronly deal with minimizing either, the trim waste or pattern changes, this paperproposes a multi-objective evolutionary algorithm to optimize the WPL objective(weighted planning level) and the cost objectives. Computational experimentswere conducted and results were compared against the current shop schedulingmethod used at a real-life corrugator manufacturing facility. A series of experimentswere also conducted to determine the evolutionary algorithm parameters. Theimprovement on performance metrics encourages us to actually implement thealgorithm at the factory

Minimización del tiempo total de flujo de tareas en una sola máquina: Estado del arte

La programación de operaciones en una sola máquina es un problema clásico de la investigación de operaciones. Numerosos métodos han sido propuestos para resolver diferentes instancias del problema, dependiendo de las restricciones impuestas y del objetivo del mismo. En este artículo estamos interesados en ilustrar el estado actual de desarrollo de los métodos y algoritmos existentes en la literatura para el problema de minimización del flujo total de tareas sujetas a fechas de llegadas, tanto en problemas estáticos como dinámicos. Además, las posibilidades de trabajo y las preguntas abiertas serán igualmente expuestas

Prevalencia de sarcopenia en adultos mayores de dos hogares geriátricos de Pereira, Colombia: Prevalence of sarcopenia in older adults in two retirement homes in Pereira, Colombia

Introduction: Is a risk factor for morbidity, mortality and disability in older adults, so its management is a priority in geriatrics. The aim of this article is to characterize a population of older adults from two geriatric homes and to establish the prevalence of sarcopenia and the degree of dependence. Methods: Cross-sectional study developed in the city of Pereira-Colombia. A population of 72 adults from 65 to 98 years of age was included, using probability sampling. Sarcopenia was determined by means of the Criteria of the European Consensus on Definition and Diagnosis of Sarcopenia, evaluating grip strength, skeletal muscle mass index, in case of sarcopenia, the severity of sarcopenia together with walking speed, and the degree of dependence according to the Barthel scale.  Results: 57 people participated. A total of 68.4% (n=39) were women. The median age was 83 years. Two percent had no sarcopenia, 9% had suspected sarcopenia, 28% had confirmed sarcopenia and 61% had severe sarcopenia. According to the Barthel scale, 31.5% were independent, 45.6% had mild, 15.8% moderate, 5.3% severe and 1.8% total dependence. Conclusions: The prevalence of sarcopenia in nursing homes in Pereira is higher compared to that reported in the literature. Similarly, being in a private nursing home does not guarantee a better physical condition and/or quality of lifeIntroducción: La sarcopenia es un factor de riesgo para morbilidad, mortalidad y discapacidad en adultos mayores, por lo que su manejo es prioridad en geriatría. El objetivo de este artículo, consiste en caracterizar una población de adultos mayores de dos hogares geriátricos y establecer la prevalencia de sarcopenia y el grado de dependencia. Métodos: Estudio de corte transversal desarrollado en la ciudad de Pereira-Colombia. Se incluyó a una población de 72 adultos desde los 65 hasta los 98 años, usando muestreo probabilístico. Se determinó la sarcopenia por medio de los Criterios del Consenso Europeo sobre Definición y Diagnóstico de Sarcopenia; evaluándose la fuerza de prensión, índice de masa muscular esquelética, en caso de presentarse sarcopenia, la severidad de esta junto a la velocidad de marcha, y el grado de dependencia según la escala de Barthel. Resultados: Participaron finalmente 57 personas. El 68,4% (n=39) eran mujeres. La mediana de la edad fue de 83 años. El 2% no presentó sarcopenia, 9% presentaban sospecha de sarcopenia, 28% tenían sarcopenia confirmada y 61% sarcopenia grave. Según la escala de Barthel, el 31,5% eran independientes, 45,6% tenían dependencia leve, 15,8% moderada, 5,3% severa y 1,8% total. Conclusiones: La prevalencia de sarcopenia en los hogares geriátricos de Pereira es mayor en comparación a la reportada en la literatura. Del mismo modo, encontrarse en un hogar geriátrico privado no garantiza una mejor condición física y/o calidad de vida