Buck-boost DC-DC converter with fractional control

This paper deals with the fractional modeling of a DC-DC buck-boost converter, suitable in solar-powered electrical generation systems, and the design of a fractional controller for the aforementioned switching converter. Although the modeling and design of the controller is carried out for this particular DC-DC converter, it can be easily extended to other kind of switching converter. In addition, the comparison between integer-order plant/controller and fractional-order plants/controller is carried out. The article also shows that, under the same design conditions, the fractional-order controller has a better performance and behaviour than the classical integer-order controller in both situations, that is, with integer-order plant and fractional-order plant models.Postprint (published version

Current-Mode One-Cycle Control Applied to Linear-Assisted DC/DC Converters

This article shows the proposal of an current-mode one-cycle control for linear-assisted DC/DC converters. Linearassisted DC/DC converters are structures that allow to take advantages of the two classic alternatives in the design of power supply systems: voltage linear regulators (classic NPN topology or LDO –low dropout–) and switching DC/DC converters. The current-mode one-cycle control technique is proposed in order to obtain the duty cycle of the linear-assisted converter switch. The proposed structure can provide an output with suitable load and line regulations. The paper shows the design and simulation results of the proposed current-mode one-cycle linear-assisted converter.Postprint (published version

Canal Identification for Fractional Linear Control Purposes

In this paper an LPV rational order control model of an irrigation canal is experimentally obtained by using the described LPV fractional identification procedure. Global LPV model is obtained from polynomial interpolation of local model parameters. Validation results demonstrate that rational order models are more accurate than integer order models. Therefore rational order models of an irrigation canal have an important role to play in management and efficient use of water resources.Postprint (published version

Evaluation of the potential of different high calorific waste fractions for the preparation of solid recovered fuels

Solid recovered fuels constitute a valuable alternative for the management of those non-hazardous waste fractions that cannot be recycled. The main purpose of this research is to assess the suitability of three different wastes from the landfill of the local waste management company (COGERSA), to be used as solid recovered fuels in a cement kiln near their facilities. The wastes analyzed were: End of life vehicles waste, packaging and bulky wastes. The study was carried out in two different periods of the year: November 2013 and April 2014. In order to characterize and classify these wastes as solid recovered fuels, they were separated into homogeneous fractions in order to determine different element components, such as plastics, cellulosic materials, packagings or textile compounds, and the elemental analysis (including chlorine content), heavy metal content and the heating value of each fraction were determined. The lower heating value of the waste fractions on wet basis varies between 10 MJ kg−1 and 42 MJ kg−1. One of the packaging wastes presents a very high chlorine content (6.3 wt.%) due to the presence of polyvinylchloride from pipe fragments, being the other wastes below the established limits. Most of the wastes analyzed meet the heavy metals restrictions, except the fine fraction of the end of life vehicles waste. In addition, none of the wastes exceed the mercury limit content, which is one of the parameters considered for the solid recovered fuels classification. A comparison among the experimental higher heating values and empirical models that predict the heating value from the elemental analysis data was carried out. Finally, from the three wastes measured, the fine fraction of the end of life vehicles waste was discarded for its use as solid recovered fuels due to the lower heating value and its high heavy metals content. From the point of view of the heating value, the end of life vehicles waste was the most suitable residue with a lower heating value of 35.89 MJ kg−1, followed by the packaging waste and the bulky waste, respectively. When mixing the wastes studied a global waste was obtained, whose classification as solid recovered fuels was NCV 1 Cl 3 Hg 3. From the empirical models used for calculating higher heating value from elemental content, Scheurer–Kestner was the model that best fit the experimental data corresponding to the wastes collected in November 2013, whereas Chang equation was the most approximate to the experimental heating values for April 2014 fractions. This difference is due to higher chlorine content of the second batch of wastes, since Chang equation is the only one that incorporates the chlorine content

Conducción anestésica en gestante con embarazo pretérmino e insuficiencia respiratoria por COVID-19. Informe de caso

Las gestantes son más susceptibles a patógenos respiratorios y neumonías severas, debido a los cambios del embarazo. El presente artículo tiene como objetivo describir la conducción anestésica en una gestante pretérmino con insuficiencia respiratoria por COVID-19. La paciente necesitó cesárea urgente con 33.3 semanas de gestación, sin antecedentes patológicos personales, ingresada en la Unidad de Cuidados Intensivos, por insuficiencia respiratoria secundaria a neumonía bilateral por COVID-19, que requirió soporte ventilatorio no invasivo.  Es anunciada para cesárea segmentaria anterior urgente, bajo anestesia neuroaxial intratecal con bupivacaína hiperbárica y oxigeno suplementario por mascarilla Venturi a 10 l/min, que mantiene estables los parámetros cardiorrespiratorios. El recién nacido obtiene apgar 7/9 y evoluciona de manera satisfactoria, al igual que la madre hasta ser dados de alta de las respectivas Unidades de Terapia Intensiva. La adecuada evaluación preoperatoria, selección y conducción anestésica, así como trazar una estrategia multidisciplinaria, constituyen los pilares para evitar complicaciones fatales.

Desarrollo de una interfaz cerebro-ordenador (BCI) para aplicaciones de robótica

En este artículo se presenta el diseño y posterior implementación física de un sistema capaz de captar las señales procedentes del cerebro. Se resumirán los conocimientos y la tecnología empleada para el desarrollo del mencionado sistema, estableciendo así un canal de comunicación natural entre el ser humano, que será el responsable de dar las órdenes, y un determinado artefacto físico, que será el que llevará a cabo la acción requerida. De esta forma, y gracias al sistema diseñado, se pretende, en forma de proof-of-concept, poder controlar, por ejemplo, el cursor de un PC o un pequeño robot móvil a través de las señales neuronales capturadas por el sistema.Postprint (published version

Historia de una institución hospitalaria de la Región Central de Cuba. Sus diferentes etapas

This present work refers to the history of the "Celestino Hernández Robau" Welfare Hospital in the Central Region of Cuba since the 1722-1723 to the present. Its development was very poor until, starting in 1959, with the triumph of the Revolution, the development of public health took a giant leap in number of beds, workers, increased budget and scientific development. In 1990 appeared the new Hospital "Arnaldo Milian Castro" and was divided among the workforce this new facility and the old.El presente trabajo refiere la historia del Hospital Asistencial “Celestino Hernández Robau” de la Región Central del Cuba desde los años 1722-1723 hasta la actualidad. Su desarrollo fue muy pobre hasta que, a partir del año 1959, con el triunfo de la Revolución, el desarrollo de la salud pública dio un salto gigantesco en número de camas, trabajadores, aumento del presupuesto y desarrollo científico. En 1990 apareció el nuevo Hospital “Arnaldo Milián Castro” y fue dividida la fuerza laboral  entre esta nueva instalación y la antigua

A fuzzy logic proposal for diagnosis multiple incipient faults in a power transformer

For the safety and continuity of service in industrial electrical systems, the availability of transformers is essential. For this reason, it is necessary to develop intelligent fault diagnosis techniques to reduce repair and maintenance costs. Recently, several methods have been developed that use artificial intelligence techniques such as neural networks, support vector machines, hybrid techniques, etc., for the diagnosis of faults in power transformers using gas analysis. These methods, although they present very good results, encounter restrictions to determine the precise moment before the occurrence of multiple fault of small magnitude and are difficult to implement in practice. This document proposes a method to diagnose multiple incipient faults in a power transformer using fuzzy logic. The proposal, based on historical data from the composition of the gases dissolved in the oil, achieves a performance in the classification of multiple incipient fault of 98.3%. With reliable samples of dissolved gas, it guarantees an overall rate of accuracy in detecting incipient faults that is superior to that obtained by the most successful conventional methods in the industry. The proposal does not encounter generalization difficulties and constitutes a simple solution that allows determining the state of the transformer in service without affecting the continuity of the electricity supply

Cromoblastomicosis

RESUMEN: La cromoblastomicosis es una infección micótica crónica de la piel y el tejido celular subcutáneo producido por hongos  pigmentados, de crecimiento lento, de la familia Dematiaceae. Se caracteriza por la producción de lesiones verrucosas, nodulares, costrosas y ulceradas que afectan generalmente las extremidades, aunque pueden observarse en otras localizaciones. Predomina en climas tropicales y subtropicales. Se presenta un caso de paciente de 65 años de edad con lesión úlceroverrucosa en la mano derecha con el diagnóstico clínico inicial de carcinoma epidermoide. Se diagnostica como cromoblastomicosis al observarse en la biopsia, las esporas pigmentadas características de la entidad