Aristóteles, Retórica.

Sin resume

A Bayesian Approach for Predicting Wind Turbine Failures based on Meteorological Conditions

With the growing wind energy sector, the need for advanced operation and maintenance (O&M) strategies has emerged. So far, mainly corrective or preventive O&M actions are applied. Predictive modelling, however, is expected to significantly enhance existing O&M practice. Here, anticipating wind turbine component failures can enable operators to lower the O&M cost and is particularly useful for wind farms located in remote areas or offshore locations. Previous research has shown that the failure behaviour of wind turbines and their components is highly influenced by the meteorological conditions under which the turbines operate. Hence, there is a significant need for robust models for failure prediction taking into consideration these conditions. Furthermore, solutions need to be found in order to determine the most suitable input variables for enhancing their prediction accuracy. This study uses failure data obtained from 984 wind turbines during 87 operational WT years. Bayesian belief networks (BBN) are trained based on failure records, technology specific covariates, as well as measurements of the environmental and operational conditions at site. Subsequently, the failure events in a wind farm during a period of 36 months are predicted with the BNN, whereas the failure events of six main components are predicted separately. Furthermore, an extensive sensitivity study is carried out to find the model with the highest prediction accuracy for each component. The influence of each meteorological, operational or technical covariate are discussed in detail. The models achieved a very good accuracy and were able to predict the majority of the component failures over the prediction period

SCADA alarms processing for wind turbine component failure detection

Wind turbine failure and downtime can often compromise the profitability of a wind farm due to their high impact on the operation and maintenance (O&M) costs. Early detection of failures can facilitate the changeover from corrective maintenance towards a pre- dictive approach. This paper presents a cost-effective methodology to combine various alarm analysis techniques, using data from the Supervisory Control and Data Acquisition (SCADA) system, in order to detect component failures. The approach categorises the alarms according to a reviewed taxonomy, turning overwhelming data into valuable information to assess component status. Then, different alarms analysis techniques are applied for two purposes: the evaluation of the SCADA alarm system capability to detect failures, and the investigation of the relation between components faults being followed by failure occurrences in others. Various case studies are presented and discussed. The study highlights the relationship between faulty behaviour in different components and between failures and adverse environmental conditions

On perfect and quasiperfect dominations in graphs

A subset S ¿ V in a graph G = ( V , E ) is a k -quasiperfect dominating set (for k = 1) if every vertex not in S is adjacent to at least one and at most k vertices in S . The cardinality of a minimum k -quasiperfect dominating set in G is denoted by ¿ 1 k ( G ). Those sets were first introduced by Chellali et al. (2013) as a generalization of the perfect domination concept and allow us to construct a decreasing chain of quasiperfect dominating numbers n = ¿ 11 ( G ) = ¿ 12 ( G ) = ... = ¿ 1 ¿ ( G ) = ¿ ( G ) in order to indicate how far is G from being perfectly dominated. In this paper we study properties, existence and realization of graphs for which the chain is short, that is, ¿ 12 ( G ) = ¿ ( G ). Among them, one can find cographs, claw-free graphs and graphs with extremal values of ¿ ( G ).Postprint (published version

Poblaciones europeas de jopo (O. cumana) virulentas en líneas de girasol con diferentes genes de resistencia

Resúmenes del XIII Congreso de la Sociedad Española de FitopatologíaPeer reviewe

Open access to educational resources in energy and sustainability: Usability evaluation prototype for repositories

The purpose of this paper is to show a PhD dissertation research plan, which aims to assess whether the users’ experience of users to perform various tasks in an open access repository, increases by integrating Discovery Tools. The tasks to perform by the users are management and information design, dissemination and searches of open educational resources (OER) of sustainability energy. This research aims to develop a usability evaluation prototype which will offer new insights in the design of the information architecture. In the first stage, the criteria will be selected to measure the level of usability of the tasks to evaluate and develop the analysis of the current interactive design of the web repository. In the second stage, will consist of measure, once implemented the Discovery Tools in the web repository and check the usability level increase in relation with the criteria. In this paper you could find aspects as the motivations and the context in which it will develop this research, state of the art, hypothesis, research objectives, aspects of the methodology of the research, developed under the method of mixed layout, the current an expected contribution, the results and the validation and dissertation status. The results will contribute for detect new criteria and parameters for provide flexible interfaces, specifically for the web repositories, which are a part of the technological ecosystem of the scientific activity

Experimental envenomation with Crotalus durissus terrificus venom in dogs treated with antiophidic serum - part I: clinical evaluation, hematology and myelogram

The present study aimed at evaluating clinical and laboratory aspects during experimental envenomation by Crotalus durissus terrificus in dogs treated with antiophidic serum. Twenty-one dogs were divided into three groups of seven animals each. Group I received 1mg/kg venom (sc); Group II received 1mg/kg venom (sc), 50mg antiophidic serum (iv), and fluid therapy including 0.9% NaCl solution (iv); and Group III received 1mg/kg venom (sc), 50mg antiophidic serum (iv), and fluid therapy including 0.9% NaCl solution containing sodium bicarbonate diluted to the dose of 4mEq/kg. The clinical signs of ataxia, sedation, flaccid paralysis, mydriasis, eyeball paralysis, mandible ptosis, sialorrhea, vomiting and diarrhea observed in the dogs were very similar to those observed in humans. The decrease in hemoglobin, hematocrit, erythrocyte, platelet and fibrinogen levels, prolongation of clotting time, prothrombin time (PT) and activated partial thromboplastin time (APTT), as well as hypocellularity in the bone marrow characterized anemia, thrombocytopenia and blood incoagulability, as well as hypofibrinogenemia and decreased bone-marrow activity. Important bleeding was not observed. Increased numbers of leukocytes and neutrophils and decreased numbers of lymphocytes and eosinophils characterized an acute inflammatory response and stress caused by generalized pain. The employed antiophidic serum was effective and all animals survived

Diagnosis of bronchial hyperresponsiveness in sport by PC20 value

En este trabajo se exponen los criterios de positividad del Comité Olímpico Internacional versus a la Sociedad Española de Neumología y Cirugía Torácica. Participaron en este estudio ochenta deportistas de alto rendimiento, realizando una historia clínica, una espirometría de reposo y un test de metacolina. Se analiza la sensibilidad y especificidad del test de metacolina mediante curvas ROC. El comité Internacional antidopaje (WADA) requiere que la disminución sea con un PC20 < a 4mg/ml, mientras que para la práctica clínica este descenso debe presentar un PC20 < 8mg/ml. Los resultados fueron: 25% tuvieron un PC20 > de 8mg/ml; el 61% obtuvieron un PC20 < 4mg/ml y un 14% presentaron un PC20 entre 4 y 8mg/ml, correspondiendo el mejor punto de corte a PC20 de 7,6mg/ml con especificidad de 98,3 y sensibilidad de 100%. Se tendría que determinar los mismos criterios para el diagnóstico de los deportistas y los que no lo son.In this work criteria of the International Olympic Committee versus the Spanish Society of Pneumology and Thoracic Surgery are exposed. A study was conducted in eighty high performance athletes of several sports . Who underwent a medical history, resting spirometry and a methacholine challenge test. You get the sensitivity and specificity of methacholine challenge test using Receiver Operating Curves (ROC curves). International anti-doping Committee requires that the decline is a PC20 < 4mg/ml, while clinical practice this fall must submit a PC20 < 8mg/ml. Twenty five percent of those studied had a PC20 > of 8mg/ml, 61% had a PC20 < 4mg/ml and 14% had a 4 to 8mg/ml PC20. The best cutoff point was found for a PC20 of 7.6 mg/ml with a specificity of 98.3 and a sensitivity of 100%. It would have to determine the same criteria for positive diagnosis of athletes and those who are not

In-depth analysis of single-diode model parameters from manufacturer’s datasheet

The objective of this paper is to determine all the possible combinations of the five parameters of the single-diode model (SDM) of a photovoltaic panel when only the following three important points (remarkable points) of a IeV curve, namely, short circuit, maximum power and open circuit points, are available, usually from manufacturer’s datasheet. In this work, four of the five parameters of the SDM are expressed as explicit functions of the remaining one. Taking advantage of this, the monotony of these functions has been studied and the intervals where the corresponding parameters belong have been determined, that is, the domain of the parameters, in terms exclusively of the remarkable points. Using these functions, a unique SDM solution can be also easily determined if an extra data or equation is available. A possible application of this study is to validate if an extra equation is compatible with the set of equations obtained from the remarkable points. The results presented in this paper have been tested with a database gathering information of 8835 datasheets included in the Energy Commission’s Solar Equipment Lists. Comparisons have also been made with other works which have tried to obtain the SDM parameters only with datasheet information