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This paper presents the design, implementation, and validation of an on-blade sensor system for remote vibration measurement for low-capacity wind turbines. The autonomous sensor system was deployed on three wind turbines, with one of them operating in harsh weather conditions in the far south of Chile. The system recorded the acceleration response of the blades in the flapwise and edgewise directions, data that could be used for extracting the dynamic characteristics of the blades, information useful for damage diagnosis and prognosis. The proposed sensor system demonstrated reliable data acquisition and transmission from wind turbines in remote locations, proving the ability to create a fully autonomous system capable of recording data for monitoring and evaluating the state of health of wind turbine blades for extended periods without human intervention. The data collected by the sensor system presented in this study can serve as a foundation for developing vibration-based strategies for real-time structural health monitoring.
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Background: Operation of wind turbines has resulted in collision fatalities for several bat species, and one proven method to reduce these fatalities is to limit wind turbine blade rotation (i.e., curtail turbines) when fatalities are expected to be highest. Implementation of curtailment can potentially be optimized by targeting times when females are most at risk, as the proportion of females limits the growth and stability of many bat populations. The Brazilian free-tailed bat (Tadarida brasiliensis) is the most common bat fatality at wind energy facilities in California and Texas, and yet there are few available data on the sex ratios of the carcasses that are found. Understanding the sex ratios of fatalities in California and Texas could aid in planning population conservation strategies such as informed curtailment. Methods: We used PCR to determine the sex of bat carcasses collected from wind energy facilities during post-construction monitoring (PCM) studies in California and Texas. In California, we received samples from two locations within the Altamont Pass Wind Resource Area in Alameda County: Golden Hills (GH) (n = 212) and Golden Hills North (GHN) (n = 312). In Texas, we received samples from three wind energy facilities: Los Mirasoles (LM) (Hidalgo County and Starr County) (n = 252), Los Vientos (LV) (Starr County) (n = 568), and Wind Farm A (WFA) (San Patricio County and Bee County) (n = 393). Results: In California, the sex ratios of fatalities did not differ from 50:50, and the sex ratio remained stable over the survey years, but the seasonal timing of peak fatalities was inconsistent. In 2017 and 2018, fatalities peaked between September and October, whereas in 2019 and 2020 fatalities peaked between May and June. In Texas, sex ratios of fatalities varied between locations, with Los Vientos being female-skewed and Wind Farm A being male-skewed. The sex ratio of fatalities was also inconsistent over time. Lastly, for each location in Texas with multiple years studied, we observed a decrease in the proportion of female fatalities over time. Discussion: We observed unexpected variation in the seasonal timing of peak fatalities in California and differences in the sex ratio of fatalities across time and facility location in Texas. In Texas, proximity to different roost types (bridge or cave) likely influenced the sex ratio of fatalities at wind energy facilities. Due to the inconsistencies in the timing of peak female fatalities, we were unable to determine an optimum curtailment period; however, there may be location-specific trends that warrant future investigation. More research should be done over the entirety of the bat active season to better understand these trends in Texas. In addition, standardization of PCM studies could assist future research efforts, enhance current monitoring efforts, and facilitate research on post-construction monitoring studies.
Assuntos
Quirópteros , Energia Renovável , Feminino , Masculino , Animais , Razão de Masculinidade , Texas/epidemiologia , Estações do AnoRESUMO
Currently, renewable energies, including wind energy, have been experiencing significant growth. Wind energy is transformed into electric energy through the use of wind turbines (WTs), which are located outdoors, making them susceptible to harsh weather conditions. These conditions can cause different types of damage to WTs, degrading their lifetime and efficiency, and, consequently, raising their operating costs. Therefore, condition monitoring and the detection of early damages are crucial. One of the failures that can occur in WTs is the occurrence of cracks in their blades. These cracks can lead to the further deterioration of the blade if they are not detected in time, resulting in increased repair costs. To effectively schedule maintenance, it is necessary not only to detect the presence of a crack, but also to assess its level of severity. This work studies the vibration signals caused by cracks in a WT blade, for which four conditions (healthy, light, intermediate, and severe cracks) are analyzed under three wind velocities. In general, as the proposed method is based on machine learning, the vibration signal analysis consists of three stages. Firstly, for feature extraction, statistical and harmonic indices are obtained; then, the one-way analysis of variance (ANOVA) is used for the feature selection stage; and, finally, the k-nearest neighbors algorithm is used for automatic classification. Neural networks, decision trees, and support vector machines are also used for comparison purposes. Promising results are obtained with an accuracy higher than 99.5%.
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RESUMEN Introducción: Los aerosoles en Estomatología constituyen un factor muy importante a tener en cuenta, pues estos facilitan con la dispersión de gotas minúsculas la trasmisión bacteriana a los trabajadores sanitarios y al medio ambiente del consultorio. Ante la presencia de la pandemia de la COVID-19, es un peligro que representa para la vida humana. Objetivo: Realizar una recopilación de información que argumente el riesgo de la transmisión del virus SARS-CoV-2 mediante el uso de aerosoles en la atención estomatológica y las medidas precisas adicionales a tener en cuenta para la prevención del contagio del personal de salud de esta área. Método: Se realizó un estudio en la Clínica Estomatológica Provincial Docente "Mártires del Moncada", de Santiago de Cuba, en el período comprendido de enero a septiembre de 2020, consistente en una revisión bibliográfica. La búsqueda se realizó en las bases de datos bibliográficos Pubmed, Medline, Science Direct, SciELO, y el buscador Google Académico, sobre la importancia de los aerosoles generados en la práctica estomatológica con relación a la actual pandemia. Resultados: La información encontrada, expresó las normas, medidas, criterios clínicos, precauciones y recomendaciones relacionados con los aerosoles en el consultorio estomatológico. Conclusiones: Además de las precauciones estándares, es imprescindible evitar el uso de instrumentos y dispositivos que generen aerosoles, ya que incrementan el riesgo de contraer el virus del SARS-CoV-2, no retirar los medios de protección en el espacio del consultorio, la necesidad de que los trabajadores dominen el conocimiento de todas las medidas, entre otras.
ABSTRACT Introduction: The use of aerosols in dental clinics represents a very important risk factor to be in focus as they could resulting in bacterial transmission to healthcare workers and entity environment through the dispersion of tiny droplets. Its use, in the presence of COVID-19 pandemic, represents a danger to human life. Objective: To gather essential information that argue the risk of SARS-CoV-2 related infection when using aerosols in dental care clinics, as well as the additional measures taken into account for preventing infection of health personnel. Method: It was conducted a bibliographic review at the Clínica Estomatológica Provincial Docente "Mártires del Moncada" in Santiago de Cuba from January to September, 2020. Searches concerning the importance of the use of aerosols in dental clinics and how to use it in this current pandemic were carried out in the data bases Pubmed, Medline, Science Direct, SciELO, and Google scholar. Results: The information found revealed norms, measures, clinical criteria, precautions and recommendations related to the use of aerosols in the dental clinic. Conclusions: In addition to standard precautions, it is essential to avoid the use of tools and devices that generate aerosols, since they increase the risk of SARS-CoV-2 infection. Also it is important not to remove the protection means use in the dental office, the need for workers to knowledge all protocol, among others important aspects.
RESUMO Introdução: Os aerossóis em Estomatologia são um fator muito importante a se levar em consideração, pois facilitam a transmissão bacteriana aos profissionais de saúde e ao ambiente de escritório com a dispersão de minúsculas gotas. Objetivo: Realizar uma compilação de informações que discutam o risco de transmissão do vírus SARS-CoV-2 através do uso de aerossóis em atendimento odontológico e as medidas adicionais precisas a serem levadas em conta para a prevenção do contágio à saúde pessoal desta área. Método: Realizou-se um estudo na Clínica Estomatológica Provincial Docente "Mártires del Moncada", em Santiago de Cuba, no período de janeiro a setembro de 2020, consistindo numa revisão bibliográfica. A busca foi realizada nas bases de dados bibliográficas Pubmed, Medline, Science Direct, SciELO e na ferramenta de busca Google Scholar, sobre a importância dos aerossóis gerados na prática odontológica em relação à atual pandemia. Resultados: As informações encontradas expressam as normas, medidas, critérios clínicos, cuidados e recomendações relacionadas aos aerossóis no consultório de Estomatologia. Conclusões: Além das precauções padrão, é imprescindível evitar o uso de instrumentos e dispositivos que gerem aerossóis, pois aumentam o risco de contrair o vírus SARS-CoV-2, não retiram os meios de proteção no ambiente de escritório, a necessidade de os trabalhadores dominarem o conhecimento de todas as medidas, entre outras.
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Thermally sprayed cermet coatings are adequate solutions to improve cavitation and wear resistance of hydraulic turbines made of stainless steel (SS), especially in rivers with a high sediment load, such as the Madeira River in Brazil. However, some cermets are easily dissolved in river water, leading to premature failure of the coating and costly maintenance. Moreover, galvanic corrosion induced by coupling the cermet to a SS can accelerate the coating dissolution. Therefore, the corrosion resistance of six cermets (WC-12Co, WC-10Ni, WC-10Co-4Cr, Cr3C2-25NiCr, Cr3C2-10NiCr and Cr3C2-10Ni) and the galvanic corrosion resistance of these materials coupled to CA6NM SS were evaluated in a solution that simulated Madeira River water. WC-12Co and WC-10Ni cermets exhibited the highest corrosion rates, 0.077 and 0.068 mm/year, respectively, whereas the Cr content in the WC-10Co-4Cr (0.017 mm/year) and Cr3C2-based coatings (0.005 to 0.007 mm/year) led them to corrode at slower rates. Moreover, the WC-10Co-4Cr and Cr3C2-based cermets exhibited negligible galvanic corrosion current when coupled to the CA6NM SS, making them good options to coat hydraulic turbines. In contrast, WC-12Co and WC-10Ni coatings underwent a more severe galvanic corrosion process, which would drastically reduce the lifespan of these materials as hydraulic turbine coatings.
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There are a wide variety of devices behaving essentially as flexible and elastic systems while interacting dynamically with fluids, usually water or air, under normal operating conditions. Interactions of this kind involve a double complexity of the dynamics, as the systems go through large deformation due to the flow actions, and simultaneously, the flow dynamics is strongly influenced by the shape adopted by the systems. The present research adapts mathematical methods, still new to the field, to represent ways of dealing with flows of fluid in bidirectional interactions with those new technologies, and particularly applies them to the exploration of vorticity wind turbines (VWT), a new kind of vertical blade-less turbine that gathers energy from the vortex induced vibrations (VIV) of a relatively short and scalable mast. This research presents a framework for such modeling by coupling the discrete element method (DEM) with the Immersed Boundary Method (IBM), for the representation of VWT; and with the finite volume method (FVM), for solving the Navier-Stokes equations. Simulations show that the VWT achieves the lock-in effect for wind velocities between 9 and 15 m/s, with efficiency values between 20 and 30%. The preliminary results together with logistic and cost-related reasons, make these devices very promising, especially when considering the difficulties of implementing new approaches in developing countries.
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The high potential of wind speed in the Colombian Caribbean coast is an opportunity to develop offshore wind energy technology. This article contains the wind speed and wind power density in four strategic locations in Colombia (Cartagena, Barranquilla, Santa Marta and La Guajira) at different elevations. The dataset from this study is related to the research paper "Renewables energies in Colombia and the opportunity for the offshore wind technology published in Journal of Cleaner Production (Rueda-Bayona et al.) [1]. Reading and processing numerous files stored in databases could be challenging because it demands software programming to do so, what could difficult the access to valuable data for the community. Also, high compressed files such as NetCDF formats demand specialised software which is not easy obtaining and utilising because it requires skills in a programming language. Then, this study used the NARR-NOAA database [2] and generated local wind and power density data stored in Excel sheets to ease their utilisation.
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Wind energy has rapidly become an important alternative among renewable energies, and it is generally considered clean. However, little is known about its impact at the level of ecological communities, especially in biodiversity hotspots. The Isthmus of Tehuantepec is a highly biodiverse region in Mesoamerica, and has the highest potential for generating wind energy in Mexico. To assess the effects of installing a wind farm on the understory bat community in a landscape of fragmented habitat, we assessed its diversity and composition over four stages of installation (site preparation, construction, and two stages of operation). We captured 919 bats belonging to 22 species. Species richness, functional diversity and phylogenetic diversity decreased during construction and the first stage of operation. However, these components of biodiversity increased during the second stage of operation, and species composition began to resemble that of the site preparation stage. No species considered as sensitive to disturbance was recorded at any stage. This is the first study to reveal the diversity of a Neotropical bat community after wind turbines begin to operate.