Plan de mantenimiento de un parque eólico

El objetivo de este Trabajo Fin de Grado es la realización de un plan de mantenimiento de un parque eólico. El plan de mantenimiento servirá para identificar y analizar los componentes del parque eólico para posteriormente realizar acciones de mantenimiento sobre ellos. De esta manera, se aumenta la vida útil tanto de los aerogeneradores como de los demás componentes del parque eólico. El plan de mantenimiento está encargado por la empresa Tenerife eólica S.A. La empresa busca construir un parque eólico en la isla de Tenerife de las islas Canarias en España. La realización del plan de mantenimiento previo a la construcción del parque eólico facilitará a la empresa saber si le resulta rentable construir este parque eólico. Por esta razón, se adjuntará en el plan de mantenimiento el presupuesto necesario para llevarlo a cabo. Sin embargo, para situar al lector, se explican una serie de conceptos para facilitar la comprensión del documento. Inicialmente, se exponen los distintos tipos de energía que existen, profundizando posteriormente en los métodos de obtención de energía más importantes en la actualidad, clasificándolos en energías renovables y energías no renovables. El parque eólico está destinado a obtener energía, debido a esto es importante conocer cómo se obtiene energía en la actualidad. El parque eólico obtiene, tal y como indica su nombre, energía eólica. Es decir, energía a partir del viento. Por esta razón, el capítulo posterior está dedicado a la energía eólica, prestándole especial atención a los aerogeneradores. Se explica tanto la evolución de los aerogeneradores, como los distintos tipos de aerogeneradores existentes. Al producir energía a partir del viento, es importante conocer el clima canario, ya que se construirá el parque eólico en Canarias. Por esta razón, se exponen los factores que influyen en el clima canario, sobre todo en los factores que influyen sobre las corrientes de viento en Canarias. El objeto del trabajo fin de grado es el mantenimiento de un parque eólico. Por esta razón, se detalla lo que es el mantenimiento. Se entra en detalle sobre los tipos de mantenimiento existentes, así como los niveles de mantenimiento. Tras exponer los niveles de mantenimiento y los tipos de mantenimiento se entra en detalle sobre lo que es un plan de mantenimiento. Tras exponer todos los conceptos, se presenta el plan de mantenimiento del parque eólico, con todas las acciones de mantenimiento que han de llevarse a cabo, así como las periodicidades y las duraciones de los mismos. Posteriormente, se detallan los recursos necesarios (tanto humanos como materiales) para elaborar finalmente el presupuesto del mismo.The objective of this project is the realization of a maintenance plan for a wind farm. The maintenance plan will serve to identify and analyze the components of the wind farm, so it is possible to carry out maintenance actions on them. This is important to increase the lifespan of both, the wind turbines and the other components of the wind farm. The maintenance plan is commissioned by the company Tenerife eólica S.A. This company seeks to build a wind farm on the island of Tenerife of the Canary Islands in Spain. The completion of the maintenance plan prior to the construction of the wind farm will make it easier for the company to know if it is profitable to build this wind farm. For this reason, the necessary budget to carry it out will be included to the maintenance plan. However, to situate the reader, a series of concepts are explained to facilitate the understanding of this document. Firstly, the most important methods of obtaining energy are exposed, classifying them in renewable energies and non-renewable energies. The wind farm is destined to obtain energy. That’s why it is important to know how energy is obtained. The wind farm obtains, as its name indicates, wind power. That is, energy from the wind. For this reason, the chapter that follows is devoted to wind energy, paying special attention to wind turbines. It explains both the evolution of wind turbines, and the various existing wind turbines. When producing energy from the wind, it is important to know the weather on the Canary Islands. For this reason, the factors that influence on the weather of the Canary Islands are exposed. Especially, the factors that influence the wind currents in the Canary Islands. As the purpose of the final degree project is the maintenance of a wind farm, the next chapter goes into detail about the different types of maintenance, as well as the different maintenance levels existing. After explaining the maintenance levels and types of maintenance, it is explained what a maintenance plan is. After presenting all the concepts, the maintenance plan of the wind farm is presented, with all the maintenance actions that have to be carried out, as well as the periodicities and durations of these actions. Subsequently, the necessary resources (both human and material) are detailed to finally elaborate the budget of the maintenance plan is exposed

The initial conditions of isolated star formation - VI. SCUBA mapping of prestellar cores

Observations have been carried out with SCUBA at the JCMT of 52 molecular cloud cores that do not contain any sign of protostellar activity. These are all therefore candidate prestellar cores, which are believed to represent the stage of star formation that precedes the formation of a protostar. 29 of the 52 cores were detected at 850 microns at varying levels of signal-to-noise ratio greater than 3 sigma at peak. The detected cores were split into 'bright' cores and `intermediate' cores, depending on their peak flux density at 850 microns. Cores with peak 850 microns flux densities greater than 170 mJy/beam were designated 'bright' (13 cores), while those flux densities below this value were designated 'intermediate' (16 cores). This dividing line corresponds to A_v~50 under typical assumptions. The data are combined with our previously published ISO data, and the physical parameters of the cores, such as density and temperature, are calculated. Detailed fitting of the bright core radial profiles shows that they are not critical Bonnor-Ebert spheres, in agreement with previous findings. However, we find that intermediate cores, such as B68 (which has previously been claimed to be a Bonnor-Ebert sphere), may in fact be consistent with the Bonnor-Ebert criterion, suggesting perhaps that cores pass through such a phase during their evolution. We make rough estimates of core lifetimes based on the statistics of detections and find that the lifetime of a prestellar core is roughly ~3x10^5 years, while that of a bright core is \~1.5x10^5 years. Comparisons with some magnetic and turbulence regulated collapse models show that no model can match all of the data. Models that are tuned to fit the total prestellar core lifetime, do not predict the relative numbers of cores seen at each stage.Comment: 23 pages, 52 figures, accepted by MNRAS, alternate PDF w/all figures available from http://www.astro.cf.ac.uk/pub/Derek.Ward-Thompson/publications.htm

Predictability of biotic stress structures plant defence evolution

To achieve ecological and reproductive success, plants need to mitigate a multitude of stressors. The stressors encountered by plants are highly dynamic but typically vary predictably due to seasonality or correlations among stressors. As plants face physiological and ecological constraints in responses to stress, it can be beneficial for plants to evolve the ability to incorporate predictable patterns of stress in their life histories. Here, we discuss how plants predict adverse conditions, which plant strategies integrate predictability of biotic stress, and how such strategies can evolve. We propose that plants commonly optimise responses to correlated sequences or combinations of herbivores and pathogens, and that the predictability of these patterns is a key factor governing plant strategies in dynamic environments.</p

Système de suivi de la stratégie de lutte contre le VIH/sida en Suisse : comportements des migrants par rapport au VIH/sida en 2005

tude s'inscrit dans le cadre du système de surveillance de deuxième génération mis en place par l'OFSP. Ce dispositif comporte d'une part un pôle de surveillance sérologique (enregistrement des nouvelles infections) et, d'autre part, un pôle de surveillance des comportements pouvant exercer une influence sur l'évolution de l'épidémie. Dans ce cadre, des études qualitatives sont réalisées auprès de populations particulièrement difficiles à atteindre par les études auprès de la population générale ou par des enquêtes spécifiques. [...] La présente étude porte sur trois de ces populations : les migrants subsahariens, les migrants sans statut légal (clandestins) , les migrants des Balkans. Les données ont été récoltées par : des entretiens préalables avec une série d'informateurs-clés ; une collecte de données sur les groupes concernés ; deux panels d'experts : un panel réalisé en Suisse romande pour les migrants subsahariens et les migrants sans statut légal et un autre réalisé en Suisse alémanique pour les migrants des Balkans. L'étude devait permettre de répondre aux questions suivantes : les données à disposition sont-elles suffisantes pour se prononcer sur la situation et son évolution ? ; Quels sont les problèmes principaux et les problèmes émergents ? ; Les données à disposition sont-elles suffisantes pour agir (si nécessaire) ? La méthode choisie (panel) est-elle suffisante dans le cadre d'une surveillance de deuxième génération ? Convient-il de procéder à des enquêtes de population ? [Extraits : Executive summary p. 5]]]> Acquired Immunodeficiency Syndrome ; HIV Infections ; Transients and Migrants ; Switzerland fre https://serval.unil.ch/resource/serval:BIB_81B5F30B7D6E.P001/REF.pdf http://nbn-resolving.org/urn/resolver.pl?urn=urn:nbn:ch:serval-BIB_81B5F30B7D6E6 info:eu-repo/semantics/altIdentifier/urn/urn:nbn:ch:serval-BIB_81B5F30B7D6E6 info:eu-repo/semantics/submittedVersion info:eu-repo/semantics/openAccess Copying allowed only for non-profit organizations https://serval.unil.ch/disclaimer application/pdf oai:serval.unil.ch:BIB_81B5FDCD395D 2022-05-07T01:21:35Z <oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd"> https://serval.unil.ch/notice/serval:BIB_81B5FDCD395D Международная конференция «Философские, эпистемологические и идеологические основы дискуссий о языке в СССР в 1917-1950 гг.» (хроника) [Compte rendu du Colloque international «Les fondements philosophiques, épistémologiques et idéologiques du discours sur la langue en Union soviétique, 1917-1950»] Velmezova, Ekaterina info:eu-repo/semantics/article article 2002 Славяноведение, no. 6, pp. 118-121 rus oai:serval.unil.ch:BIB_81A3AB6BD008 2022-05-07T01:21:35Z <oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd"> https://serval.unil.ch/notice/serval:BIB_81A3AB6BD008 Evaluation of a low-dose CT protocol with oral contrast for assessment of acute appendicitis. info:doi:10.1007/s00330-008-1164-x info:eu-repo/semantics/altIdentifier/doi/10.1007/s00330-008-1164-x info:eu-repo/semantics/altIdentifier/pmid/18797875 Platon, A. Jlassi, H. Rutschmann, O.T. Becker, C.D. Verdun, F.R. Gervaz, P. Poletti, P.A. info:eu-repo/semantics/article article 2009 European Radiology, vol. 19, no. 2, pp. 446-454 info:eu-repo/semantics/altIdentifier/pissn/1432-1084[electronic] <![CDATA[The aim of this study was to evaluate a low-dose CT with oral contrast medium (LDCT) for the diagnosis of acute appendicitis and compare its performance with standard-dose i.v. contrast-enhanced CT (standard CT) according to patients' BMIs. Eighty-six consecutive patients admitted with suspicion of acute appendicitis underwent LDCT (30 mAs), followed by standard CT (180 mAs). Both examinations were reviewed by two experienced radiologists for direct and indirect signs of appendicitis. Clinical and surgical follow-up was considered as the reference standard. Appendicitis was confirmed by surgery in 37 (43%) of the 86 patients. Twenty-nine (34%) patients eventually had an alternative discharge diagnosis to explain their abdominal pain. Clinical and biological follow-up was uneventful in 20 (23%) patients. LDCT and standard CT had the same sensitivity (100%, 33/33) and specificity (98%, 45/46) to diagnose appendicitis in patients with a body mass index (BMI) &gt;or= 18.5. In slim patients (BMI&lt;18.5), sensitivity to diagnose appendicitis was 50% (2/4) for LDCT and 100% (4/4) for standard CT, while specificity was identical for both techniques (67%, 2/3). LDCT may play a role in the diagnostic workup of patients with a BMI &gt;or= 18.5

Profiling filaments: comparing near-infrared extinction and submillimetre data in TMC-1

Interstellar filaments are an important part of star formation. To understand the structure of filaments, cross-section profiles are often fitted with Plummer profiles. This profiling is often done with submm studies, such as Herschel. It would be convenient if filament properties could also be studied using groundbased NIR data. We compare the filament profiles obtained by NIR extinction and submm observations to find out if reliable profiles can be derived using NIR data. We use J-, H-, and K-band data of a filament north of TMC-1 to derive an extinction map from colour excesses of background stars. We compare the Plummer profiles obtained from extinction maps with Herschel dust emission maps. We present 2 methods to estimate profiles from NIR: Plummer profile fits to median Av of stars or directly to the Av of individual stars. We compare the methods by simulations. In simulations extinction maps and the new methods give correct results to within ~10-20 for modest densities. Direct fit to data on individual stars gives more accurate results than extinction map, and can work in higher density. In profile fits to real observations, values of Plummer parameters are generally similar to within a factor of ~2. Although parameter values can vary significantly, estimates of filament mass usually remain accurate to within some tens of per cent. Our results for TMC-1 are in agreement with earlier results. High resolution NIR data give more details, but 2MASS data can be used to estimate profiles. NIR extinction can be used as an alternative to submm observations to profile filaments. Direct fits of stars can also be a valuable tool. Plummer profile parameters are not always well constrained, and caution should be taken when making fits. In the evaluation of Plummer parameters, one can use the independence of dust emission and NIR data and the difference in the shapes of the confidence regions.Comment: accepted to Astronomy & Astrophysics; abstract has been shortened for astrop

The initial conditions of isolated star formation -- IX. Akari mapping of an externally heated pre-stellar core

We present observations of L1155 and L1148 in the Cepheus molecular cloud, taken using the FIS instrument on the Akari satellite. We compare these data to submillimetre data taken using the SCUBA camera on the JCMT, and far-infrared data taken with the ISOPHOT camera on board the ISO satellite. All of the data show a relation between the position of the peak of emission and the wavelength for the core of L1155. We interpret this as a temperature gradient. We fit modified blackbody curves to the spectral energy distributions at two positions in the core and see that the central core in L1155 (L1155C) is approximately 2 degrees warmer at one edge than it is in the centre. We consider a number of possible heating sources and conclude that the A6V star BD+67 1263 is the most likely candidate. This star is at a distance of 0.7 pc from the front of L1155C in the plane of the sky. We carry out radiative transfer modelling of the L1155C core including the effects from the nearby star. We find that we can generate a good fit to the observed data at all wavelengths, and demonstrate that the different morphologies of the core at different wavelengths can be explained by the observed 2 degree temperature gradient. The L1148 core exhibits a similar morphology to that of L1155C, and the data are also consistent with a temperature gradient across the core. In this case, the most likely heating source is the star BD197053. Our findings illustrate very clearly that the apparent observed morphology of a pre-stellar core can be highly dependent on the wavelength of the observation, and that temperature gradients must be taken into account before converting images into column density distributions. This is important to note when interpreting Akari and Spitzer data and will also be significant for Herschel data.Comment: 15 pages, 15 figures, accepted by MNRA

The prestellar and protostellar population of R Coronae Australis

We present 450 and 850 um maps of R Coronae Australis. We compare the maps to previous surveys of the region, and shed new light on the previously unknown nature of the protostellar sources at the centre of the cloud. We clarify the nature of two millimetre sources previously discovered in lower resolution data. We identify one new Class 0 protostar that we label SMM 1B, and we measure the envelope masses of a number of more evolved protostars. We identify two new prestellar cores that we call SMM 1A and SMM 6.Comment: 8 page