Diagnóstico de motores eléctricos para la localización de fallas incipientes

En este trabajo se presenta la exploración de metodologías de diagnóstico basadas en el análisis de vibraciones y sonido, debido a que cada señal amplifica mejor la presencia de un tipo de avería, y que, frente a un motor con un funcionamiento sospechoso, resulta conveniente combinar la información de cada una de ellas. Una de las contribuciones de este trabajo es una nueva metodología de análisis para la detección de fallas en motores de inducción en estado estacionario. El diagnóstico de las fallas se hace por medio del análisis de señales de sonido y los resultados se corroboran con el análisis de señales de vibración. Además, en este trabajo también se presenta un estudio comparativo de diferentes técnicas de análisis tiempo-frecuencia a que pueden utilizarse para detectar fallas en motores de inducción analizando señales de vibración durante el transitorio de arranque del motor.Departamento de Ingeniería EléctricaDoctorado en Ingeniería Industria

Differences in plant cover and species composition of semiarid grassland communities of central Mexico and its effects on net ecosystem exchange

"Changes in land use across the semiarid grasslands of northern Mexico have driven a decline of plant cover and alteration of plant species composition. A number of different plant communities have resulted from these changes. Their implications, however, on the carbon (C) cycle and regional carbon balance are still poorly understood. Here, we examined the effects of plant cover loss and changes in species composition on net ecosystem CO2 exchange (NEE) and their biotic and abiotic controls. NEE was measured in five representative plant community types within a semiarid grassland by temporarily enclosing the entire aboveground ecosystem using a chamber method (i.e., geodesic dome). Sites included an oat crop (crop), a moderately grazed grassland (moderate grazing), a 28 yr-old grazing exclosure (exclosure), an overgrazed site with low perennial grass cover (overgrazed), and an overgrazed site presenting shrub encroachment (shrub encroachment). For natural vegetation, rates of standardized daytime NEE for sites with a high plant cover (exclosure and moderate grazing) were similar (P > 0.05) as compared to sites with low plant cover (overgrazed and shrub encroachment). However, yearly total nighttime NEE (carbon loss) was more than double (P < 0.05) for sites with high plant cover compared to sites with low cover, resulting to slight C sinks for the low plant cover sites, and neutral or sources for the high plant cover sites as accounted by daytime and nighttime NEE annual balance. Differences in plant cover and its associated biomass defined the sensitivity to environmental controls. Thus, daytime NEE in low plant cover sites reached light compensation points at lower photosynthetic photon flux density than those from high plant cover sites. Differences in species composition did not influence NEE rates even though there were transient or permanent changes in C3 vs. C4 functional groups. Our results allowed the detection of the large variability and contribution of different plant communities to regional C balance in patchy landscapes. Identification of the role of landscape patches in the regional C balance as either sinks or sources may provide tools allowing land use management strategies that could favor C uptake in patchy landscapes.

Damage assessment in a stiffened composite panel using non-linear data-driven modelling and ultrasonic guided waves

Structural components made of composite materials are being used more often in aerospace and aeronautic structures due to their well-known properties such as high mass specific stiffness and strength. However, their application also increases the analysis complexity of such structures. Structural health monitoring (SHM) systems for these structures aim to determine the status of the system in real time such that a longer safe life and lower operational costs can be guaranteed. On that account, this paper is concerned with the experimental validation of a structural health monitoring methodology where a damage detection and classification scheme based on an acousto-ultrasonic (AU) approach is applied to a composite panel incorporating stiffening elements using a piezoelectric active sensor network in conjunction with time-frequency multiresolution analysis and non-linear feature extraction. Therefore, structural dynamic responses from the simplified aircraft composite skin panel are collected and signal features are then extracted with a signal processing and data fusion methodology in terms of the wavelet transform technique and hierarchical non-linear principal component analysis. A critical comparison with linear feature extraction methods indicates that the proposed method outperforms the traditional linear methods for the purpose of damage classification. Additionally, results show that all the damages were detectable and classifiable, and the selected features proved capable of separating all damage conditions from the undamaged state.Postprint (published version

Cognitive profile of acute post-traumatic stress disorder of victims from a car bomb attack in Colombia

ABSTRACT: The cognitive profile of car bomb victims in Colombia relating to acute post-traumatic stress syndrome is being studied descriptively and transversely. The case group consists of: 16 victims that fall into the criteria of the diagnostics of acute pot-traumatic stress, 8 subjects that witnessed the attack did not meet the requirements and 16 another are the control group. In the three groups we applied the use of the Checklist from DSM-IV and the Mini International Neuropsychiatric Interview to confirm the diagnostic. As well the use of Escala de estrategias de coping modificada (the modified copy of School of Strategies) and the Young Schema Questionnaire Long Form. Between the three groups we encountered significant differences of early maladaptive schemas and copying strategies.RESUMEN: Se estudia descriptiva y transversalmente el perfil cognitivo de víctimas de un atentado con carro bomba en Colombia y que presentan el síndrome de estrés postraumático agudo. El grupo de casos lo conformaron 16 víctimas que cumplieron los criterios diagnósticos del síndrome de estrés postraumático tipo agudo, 8 sujetos que aunque presenciaron el atentado no cumplieron los criterios y 16 sujetos de control. En los tres grupos se aplicó el Check list realizado desde el DSM-IV y se confirmó el diagnóstico con el Mini International Neuropsychiatric Interview. Se emplearon la Escala de estrategias de coping modificada y el Young Schema Questionnaire Long Form. Se encuentran diferencias significativas entre los tres grupos en Esquemas Maladaptivos Tempranos y en estrategias de afrontamiento.

Structural health monitoring by means of strain field pattern recognition on the basis of PCA and automatic clustering techniques based on SOM

Peer ReviewedPostprint (published version

Evaluación de algunos parámetros de calidad del agua en un sistema cerrado de recirculación para la acuicultura, sometido a diferentes cargas de biomasa de peces

Utilizing different loadings of biomass of the Nile Tilapia Oreochromis niloticus and rainbow trout Oncorhynchus mykiss, some water quality parameters were evaluated in a closed aquaculture recirculating system. The systems is integrated by six culture tanks, a sedimentation cistern, two submerged bio-filters, a fast sand filter, two pumps, a reconditioning-water reservoir and a unit of ultraviolet light lamps. Fishes were fed twice a day for 120 days with 2% of their total biomass. The following water quality parameters were recorded: water temperature, dissolved oxygen, pH, total ammonium nitrogen (TAN), ammonia, nitrate and chemical oxygen demand. The data were analyzed with a one-way ANOVA to determine statistical differences in the components of the system. The average values of TAN and nitrate indicated a high efficiency of the nitrification process at different fish loading of biomass. About 50% of TAN and more than 90% of ammonia was stripped into the atmosphere and this explains the low levels measured in the other components of the system. Other causes that contribute to the removal of nitrogen compounds were the assimilation by microorganism accumulated in the bottom of the sedimentation tank and the absorption and adsorption by the sludge. Results showed that the water quality parameters were satisfactory for 99% survivorship and an acceptable growth rate for both fish species.El objetivo de este estudio, fue evaluar algunos parámetros de calidad del agua en un sistema cerrado de recirculación utilizado en la acuicultura, sometido a distintas cargas de biomasa de Tilapia del NiloOreochromis niloticus y de trucha arco iris Oncorhynchus mykiss. El sistema consiste de seis estanques de cultivo, una cisterna de sedimentación, dos piletas con biofiltros sumergidos, un filtro de arena rápido, dos bombas, una pileta de reacondicionamiento y una unidad de lámparas de luz ultravioleta. Los peces fueron alimentados durante 120 días dos veces al día con el 2% de su biomasa total. Se registraron los siguientes parámetros de calidad del agua: temperatura, oxígeno disuelto, pH, nitrógeno amoniacal total (NAT), amoniaco, nitrato y demanda química de oxígeno. Los datos se analizaron con un ANDEVA de una sola vía para detectar diferencias significativas entre los componentes del sistema. Los valores promedio de NAT y nitrato indicaron una alta eficiencia en los procesos de nitrificación, aún cuando el sistema fue sometido a diferentes cargas de biomasa de peces. Los bajos valores detectados de NAT y amoniaco se debieron al arrastre eficiente hacia la atmósfera (50% NAT y más del 90% respectivamente). Otras posibles causas que contribuyeron a la eliminación de los compuestos nitrogenados, fueron la asimilación por microorganismos presentes en los lodos acumulados en la cisterna de sedimentación, además de la absorción y la adsorción por los lodos. Los resultados mostraron que la calidad del agua mantenida en el sistema permitió el 99% de sobrevivencia de ambas especies y una tasa de crecimiento aceptable

Chemical abundances in Orion protoplanetary discs: integral field spectroscopy and photoevaporation models of HST 10

Photoevaporating protoplanetary discs (proplyds) in the vicinity of hot massive stars, such as those found in Orion, are important objects of study for the fields of star formation, early disc evolution, planetary formation and H II region astrophysics. Their element abundances are largely unknown, unlike those of the main-sequence stars or the host Orion nebula. We present a spectroscopic analysis of the Orion proplyd HST 10, based on integral field observations with the Very Large Telescope/FLAMES fibre array with 0.31 × 0.31 arcsec2 spatial pixels. The proplyd and its vicinity are imaged in a variety of emission lines across a 6.8 × 4.3 arcsec2 area. The reddening, electron density and temperature are mapped out from various line diagnostics. The abundances of helium, and eight heavy elements, are measured relative to hydrogen using the direct method based on the [O III] electron temperature. The abundance ratios of O/H and S/H are derived without resort to ionization correction factors. We construct dynamic photoevaporation models of HST 10 with the CLOUDY microphysics code that validate the oxygen and sulphur abundances. With the exception of [O I] λ6300 and [S II] λ4069, the model fit is satisfactory for all spectral lines arising from the proplyd. The models show that the classic ionization correction factor for neon significantly underestimates (0.4 dex) this element's abundance in the low ionization conditions of HST 10. Apart from iron, whose gas-phase abundance is ∼0.3 dex lower than in the local Orion nebula, most other elements in the proplyd do not show substantially different gas-phase abundances from the nebula. The abundances of carbon, oxygen and neon in HST 10 are practically the same as those in B-type stars in Orion

Empoderamiento del alumnado adulto y de las personas mayores para una ciudadanía activa

Esta obra reúne iniciativas y experiencias de sensibilización y formación del profesorado y del alumnado adulto y mayor hacia una educación en competencias que contribuya a desarrollar la práctica de una ciudadanía activa compartiendo el tiempo libre, los conocimientos y las experiencias en proyectos sociales que consoliden y mejoren el entramado social de la ciudad, de las personas que la habitan y de la atención a sus necesidades. Su origen fue el proyecto CiudAct cofinanciado por el Programa Erasmus+ de la Unión Europea y en su desarrollo ha intervenido un equipo interinstitucional liderado por el Aula de Mayores+55 de la Universidad de Málaga y participado por el Centro de Profesorado «José Rodríguez Galán» de Antequera, la Asociación Cívica para la Prevención (ACP), la Asociación de Igualdad de Género Universitario (AIGU), y el Ayuntamiento de Faraján (Málaga). Con ellos, y con otras tantas instituciones y sus respectivos consorcios locales en toda Europa, se participa en la red supranacional Ciudades en Crecimiento.Programa Erasmus+ de la Unión Europea (referencia de proyecto 2015-1-ES01-KA104-014944