153 research outputs found
Control de la dinàmica en Piles de Combustible de tipus PEM
En el Projecte Final de Carrera que es presenta a continuació es desenvolupa la modelització i el control realitzat sobre una Pila de Combustible de Membrana Polimèrica (PEMFC – Proton Exchange Membrana Fuel Cell) emprada com a sistema de producció d’energia per al sector del transport.
Les piles de combustible ofereixen un sistema de producció d’energia respectuós amb el medi ambient i de gran eficiència, adequat en el món de l’automoció. Actualment es troben sota un desenvolupament intensiu per part de diversos fabricants tant per aplicacions estacionàries com mòbils.
Per realitzar l’estudi de control s’ha implementat un model no-lineal del sistema basat en principis físics, que captura diversos comportaments transitoris, a partir del paquet de software Matlab. La implementació d’aquest model, i la seva posterior linealització en diferents punts d’operació, permet l’ús de diverses tècniques d’anàlisi lineal utilitzades per establir quines són les estructures de control més adients segons les necessitats requerides. L’estudi s’ha basat en un model matemàtic per a la pila de combustible àmpliament utilitzat en la bibliografia existent i sobre el que s’han realitzat diverses modificacions, les quals han sigut analitzades en detall.
El disseny dels controladors s’ha centrat en la utilització de controladors PID, solució àmpliament adoptada per la indústria i de fàcil implementació. Aquests controladors s’han dissenyat per tal de poder satisfer les necessitats considerades pel correcte funcionament del sistema estudiat, com són les oscil·lacions del sistema, la rapidesa en la seva resposta i el manteniment de l’estabilitat. S’han analitzat diversos possibles controladors per poder cobrir diferents escenaris sota els quals es pot veure afectat el sistema.
Per últim es mostren les simulacions i resultats obtinguts, dels quals es conclou la viabilitat d’utilització de diverses estructures de control i la possibilitat de garantir les especificacions utilitzant un controlador PI descentralitzat
Single-electron transport in electrically tunable nanomagnets
We study a single-electron transistor (SET) based upon a II–VI semiconductor quantum dot doped with a single-Mn ion. We present evidence that this system behaves like a quantum nanomagnet whose total spin and magnetic anisotropy depend dramatically both on the number of carriers and their orbital nature. Thereby, the magnetic properties of the nanomagnet can be controlled electrically. Conversely, the electrical properties of this SET depend on the quantum state of the Mn spin, giving rise to spin-dependent charging energies and hysteresis in the Coulomb blockade oscillations of the linear conductance.This work has been financially supported by MEC-Spain (Grants No. FIS200402356, No. MAT2005-07369-C03-03, and the Ramon y Cajal Program) and by CAV (No. GV05-152)
An in-depth look at media subsidies in Spain's autonomous communities in 2019
This article focuses on public subsidies for the communication media in Spain for the year 2019, presenting an in-depth analysis of the situation. State subsidies for media is a phenomenon that became widespread in Europe during the 1960s and 1970s. In Spain, they were regulated in the 1980s, but shortly thereafter the state almost completely halted its support, and it was Spain's autonomous regions who then promoted the subsidies. In the midst of the professional debate about whether it is possible to reinstate this support from the Spanish government because of the coronavirus crisis, we identify nine autonomous regions which promote these types of subsidies. Through a study that is both prospective and propositional, our analysis will thoroughly examine the institutions granting subsidies, the sectors benefiting from them, their aim and justification, and the margin of discretionary compliance with which they are granted. Keywords: communication media, public subsidies, autonomous regions, regulation.En el presente artículo se aborda la situación de las subvenciones a los medios de comunicación en España en 2019, con la finalidad de aportar una radiografía de la situación. Las ayudas públicas a los medios de comunicación son un fenómeno extendido por Europa entre los años sesenta y setenta del siglo XX. En España se regularon en los años ochenta, pero poco después el Estado prácticamente las abandonó y fueron las comunidades autónomas quienes las impulsaron. En pleno debate profesional sobre la posibilidad de retomar estas ayudas desde el Gobierno español por la crisis del coronavirus, se han identificado nueve comunidades autónomas que promueven este tipo de subsidios. A modo prospectivo y propositivo, el análisis profundiza en las instituciones que conceden las ayudas, los sectores beneficiarios de las mismas, su finalidad y justificación y el margen de discrecionalidad con el que se conceden
Programación didáctica : módulo profesional CFGS DAM-Bases de datos
Máster Universitario en Formación del Profesorado de ESO, Bachillerato, Formación Profesional y Enseñanza de Idiomas. Especialidad en Tecnología (M090
Control de la dinàmica en Piles de Combustible de tipus PEM
En el Projecte Final de Carrera que es presenta a continuació es desenvolupa la modelització i el control realitzat sobre una Pila de Combustible de Membrana Polimèrica (PEMFC – Proton Exchange Membrana Fuel Cell) emprada com a sistema de producció d’energia per al sector del transport.
Les piles de combustible ofereixen un sistema de producció d’energia respectuós amb el medi ambient i de gran eficiència, adequat en el món de l’automoció. Actualment es troben sota un desenvolupament intensiu per part de diversos fabricants tant per aplicacions estacionàries com mòbils.
Per realitzar l’estudi de control s’ha implementat un model no-lineal del sistema basat en principis físics, que captura diversos comportaments transitoris, a partir del paquet de software Matlab. La implementació d’aquest model, i la seva posterior linealització en diferents punts d’operació, permet l’ús de diverses tècniques d’anàlisi lineal utilitzades per establir quines són les estructures de control més adients segons les necessitats requerides. L’estudi s’ha basat en un model matemàtic per a la pila de combustible àmpliament utilitzat en la bibliografia existent i sobre el que s’han realitzat diverses modificacions, les quals han sigut analitzades en detall.
El disseny dels controladors s’ha centrat en la utilització de controladors PID, solució àmpliament adoptada per la indústria i de fàcil implementació. Aquests controladors s’han dissenyat per tal de poder satisfer les necessitats considerades pel correcte funcionament del sistema estudiat, com són les oscil·lacions del sistema, la rapidesa en la seva resposta i el manteniment de l’estabilitat. S’han analitzat diversos possibles controladors per poder cobrir diferents escenaris sota els quals es pot veure afectat el sistema.
Per últim es mostren les simulacions i resultats obtinguts, dels quals es conclou la viabilitat d’utilització de diverses estructures de control i la possibilitat de garantir les especificacions utilitzant un controlador PI descentralitzat
Validation of the Scale of Basic Psychological Needs towards Physical Exercise, with the Inclusion of Novelty
The purpose of this study was to validate and adapt to the Spanish context of Physical Education, the Spanish version of the Scale of Basic Psychological Needs in the context of physical exercise, with the incorporation of novelty to the scale. The sample that took part in the study was 2372 people from 16 to 48 years old from the province of Almeria. In order to analyze the psychometric properties of the scale, several analyses have been carried out. The results have offered support both for the eight-factor structure and for the higher-order double model where the eight subscales are joined into two constructs called frustration and satisfaction. The structure of both models was invariant with respect to gender and age. Cronbach’s alpha values were above 0.70 in the subscales and scales; and adequate levels of temporal stability. In addition, the subfactors pertaining to the satisfaction of basic psychological needs positively predicted the intrinsic motivation for physical activity, while each of the subfactors of the frustration of psychological needs predicted it negatively. The results of this study provide evidence of the reliability and validity of the BPNS in the Spanish context of physical activity
PLS-based soft-sensor to predict ammonium concentration evolution in hollow fibre membrane contactors for nitrogen recovery
[EN] Hollow fibre membrane contactors (HFMC) have emerged as a promising technology for nitrogen-recovery that can be implemented in wastewater treatment plants (WWTPs) to promote circular economy. In this process, a hydrophobic membrane allows the transference of free-ammonia across the hollow fibres. During its operation, the ammonium concentration decreases, and real-time measurements would be of great value for process monitoring, optimization and control. Ammonium probes exist, but they are expensive and present noticeably maintenance costs. In this work, results from eight N-recovery experiments performed at different pH values using real supernatant of a full-scale anaerobic digester were analysed in terms of the time-evolution profiles of pH and total ammonium nitrogen (TAN). The pH revealed to carry relevant information related to the TAN concentration, as it decreased in the feed solution due to free ammonia stripping. The pH is an inexpensive-to measure process variable that can be routinely acquired in any WWTP. Therefore, a data-driven soft-sensor has been developed. It uses the pH, its derivative, and the pH increments after each reagent dosing as input signals, to estimate the TAN concentration via PLS. An extended PLS-model incorporating interaction terms, quadratic and cubic forms of the three input variables improved the TAN concentration estimation. The developed soft-sensor was able to accurately reproduce the evolution of TAN concentration (in the range 0-1000 mgNH(4)(+)-N/L with R-2 > 0.97 and RMSE < 40 mg/L) during the HFMC process operation, thus making it possible to monitor the process as well as enabling future development of different control and optimization strategies.This research was financially supported by the Spanish Ministry of Economy and Competitiveness (MINECO projects CTM2014-54980-C2-1/2-R and CTM2017-86751-C2-1/2-R) with the European Regional Development Fund (ERDF) as well as the Universitat Polite`cnica de Vale`ncia via a pre-doctoral FPI fellowship to Guillermo Noriega.Aguado García, D.; Noriega-Hevia, G.; Ferrer, J.; Seco, A.; Serralta Sevilla, J. (2022). PLS-based soft-sensor to predict ammonium concentration evolution in hollow fibre membrane contactors for nitrogen recovery. Journal of Water Process Engineering. 47:1-7. https://doi.org/10.1016/j.jwpe.2022.102735174
Models of Sports Management in Fitness Centres. Influence of Sex, Age and Sport Frequency. Linear Models vs. Qualitative Comparative Analysis
Knowing the perceptions of users of sports services has always been an object of analysis
within sports management. This paper attempts to analyse what influences the satisfaction and
future intentions of fitness centre customers, beyond management variables, by using two different
methodologies. A sample of 389 users of a private sports centre was used. Both linear relationships
between variables and the combination of sets were analysed using fuzzy set Qualitative Comparative
Analysis fsQCA. It is concluded that management variables (service quality, satisfaction and perceived
value) are very important for the prediction of management models, but that, according to the
interaction methodology between variables, both frequency and sociodemographic variables play
an important role in achieving satisfied and loyal users of the sports service. For the prediction of
customers’ future intentions, within the analysed sets, it is observed that satisfaction and perceived
value are the most predictive variables (raw coverage 0.66). Therefore, and as a consequence, a high
number of satisfied and loyal users of the service will allow the economic viability of this service to
be achieved.Ciencias de la Actividad Física y del Deport
Effect of pH and HNO2 concentration on the activity of ammonia-oxidizing bacteria in a partial nitritation reactor
Ammonia-oxidizing bacteria (AOB) are very sensitive to environmental conditions and wastewater treatment plant operational parameters. One of the most important factors affecting their activity is
pH. Its effect is associated with: NH3/NH4 þ and HNO2/NO2 chemical equilibriums and biological reaction rates. The aim of this study was to quantify and model the effect of pH and free nitrous acid
(FNA) concentration on the activity of AOB present in a lab-scale partial nitritation reactor. For this purpose, two sets of batch experiments were carried out using biomass from this reactor.
Fluorescent in situ hybridization analysis showed that Nitrosomona eutropha and Nitrosomona europaea species were dominant in the partial nitritation reactor (>94%). The experimental results
showed that FNA inhibits the AOB activity. This inhibition was properly modelled by the noncompetitive inhibition function and the half inhibition constant value was determined as 1.32 mg
HNO2-N L 1. The optimal pH for these AOB was found to be in the range 7.4 7.8. The pH inhibitory effect was stronger at high pH values than at low pH values. Therefore, an asymmetric inhibition
function was proposed to represent the pH effect on these bacteria. A combination of two sigmoidal functions was able to reproduce the experimental results obtained.Claros Bedoya, JA.; Jiménez Douglas, E.; Aguado García, D.; Ferrer, J.; Seco Torrecillas, A.; Serralta Sevilla, J. (2013). Effect of pH and HNO2 concentration on the activity of ammonia-oxidizing bacteria in a partial nitritation reactor. Water Science and Technology. 67(11):2587-2594. doi:10.2166/wst.2013.132S25872594671
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