110 research outputs found

    Fundamental frequency suppression for the detection of broken bar in induction motors at low slip and frequency

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    ProducciĂłn CientĂ­ficaBroken rotor bar (BRB) is one of the most common failures in induction motors (IMs) these days; however, its identification is complicated since the frequencies associated with the fault condition appear near the fundamental frequency component (FFC). This situation gets worse when the IM slip or the operation frequency is low. In these circumstances, the common techniques for condition monitoring may experience troubles in the identification of a faulty condition. By suppressing the FFC, the fault detection is enhanced, allowing the identification of BRB even at low slip conditions. The main contribution of this work consists of the development of a preprocessing technique that estimates the FFC from an optimization point of view. This way, it is possible to remove a single frequency component instead of removing a complete frequency band from the current signals of an IM. Experimentation is performed on an IM operating at two different frequencies and at three different load levels. The proposed methodology is compared with two different approaches and the results show that the use of the proposed methodology allows to enhance the performance delivered by the common methodologies for the detection of BRB in steady state.CONACyT scholarship (415315)Project FOFI-UAQ 2018 FIN201812PRODEP UAQ-PTC-385 gran

    Power consumption analysis of electrical installations at healthcare facility

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    ProducciĂłn CientĂ­ficaThis paper presents a methodology for power consumption estimation considering harmonic and interharmonic content and then it is compared to the power consumption estimation commonly done by commercial equipment based on the fundamental frequency, and how they can underestimate the power consumption considering power quality disturbances (PQD). For this purpose, data of electrical activity at the electrical distribution boards in a healthcare facility is acquired for a long time period with proprietary equipment. An analysis in the acquired current and voltage signals is done, in order to compare the power consumption centered in the fundamental frequency with the generalized definition of power consumption. The results obtained from the comparison in the power consumption estimation show differences between 4% and 10% of underestimated power consumption. Thus, it is demonstrated that the presence of harmonic and interharmonic content provokes a significant underestimation of power consumption using only the power consumption centered at the fundamental frequency.SEP-CONACYT, under grant 222453-2013FOMIX, under grant QRO-2014-C03-250269FOFIUAQ-FIN20161

    Spectral kurtosis based methodology for the identification of stationary load signatures in electrical signals from a sustainable building

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    Producción CientíficaThe increasing use of nonlinear loads in the power grid introduces some unwanted effects, such as harmonic and interharmonic contamination. Since the existence of spectral contamination causes waveform distortion that may be harmful to the loads that are connected to the grid, it is important to identify the frequency components that are related to specific loads in order to determine how relevant their contribution is to the waveform distortion levels. Due to the diversity of frequency components that are merged in an electrical signal, it is a challenging task to discriminate the relevant frequencies from those that are not. Therefore, it is necessary to develop techniques that allow performing this selection in an efficient way. This paper proposes the use of spectral kurtosis for the identification of stationary frequency components in electrical signals along the day in a sustainable building. Then, the behavior of the identified frequencies is analyzed to determine which of the loads connected to the grid are introducing them. Experimentation is performed in a sustainable building where, besides the loads associated with the normal operation of the building, there are several power electronics equipment that is used for the electric generation process from renewable sources. Results prove that using the proposed methodology it is possible to detect the behavior of specific loads, such as office equipment and air conditioning.Universidad de Valladolid y Consejo Mexicano de Ciencia y Tecnología (CONACYT) - (grant 743842)Universidad Autónoma de Querétaro, Fondo para el Desarrollo del Conocimiento (FONDEC-UAQ 2020) - (project FIN202011

    Annual variation in the levels of transcripts of sex-specific genes in the mantle of the common mussel, Mytilus edulis

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    Mytilus species are used as sentinels for the assessment of environmental health but sex or stage in the reproduction cycle is rarely considered even though both parameters are likely to influence responses to pollution. We have validated the use of a qPCR assay for sex identification and related the levels of transcripts to the reproductive cycle. A temporal study of mantle of Mytilus edulis found transcripts of male-specific vitelline coat lysin (VCL) and female-specific vitelline envelope receptor for lysin (VERL) could identify sex over a complete year. The levels of VCL/VERL were proportional to the numbers of sperm/ova and are indicative of the stage of the reproductive cycle. Maximal levels of VCL and VERL were found in February 2009 declining to minima between July - August before increasing and re-attaining a peak in February 2010. Water temperature may influence these transitions since they coincide with minimal water temperature in February and maximal temperature in August. An identical pattern of variation was found for a cryptic female-specific transcript (H5) but a very different pattern was observed for oestrogen receptor 2 (ER2). ER2 varied in a sex-specific way with male > female for most of the cycle, with a female maxima in July and a male maxima in December. Using artificially spawned animals, the transcripts for VCL, VERL and H5 were shown to be present in gametes and thus their disappearance from mantle is indicative of spawning. VCL and VERL are present at equivalent levels in February and July-August but during gametogenesis (August to January) and spawning (March to June) VCL is present at lower relative amounts than VERL. This may indicate sex-specific control mechanisms for these processes and highlight a potential pressure point leading to reduced reproductive output if environmental factors cause asynchrony to gamete maturation or release

    Acceptability and feasibility of a virtual community of practice to primary care professionals regarding patient empowerment: A qualitative pilot study

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    Background: Virtual communities of practice (vCoPs) facilitate online learning via the exchange of experiences and knowledge between interested participants. Compared to other communities, vCoPs need to overcome technological structures and specific barriers. Our objective was to pilot the acceptability and feasibility of a vCoP aimed at improving the attitudes of primary care professionals to the empowerment of patients with chronic conditions. Methods: We used a qualitative approach based on 2 focus groups: one composed of 6 general practitioners and the other of 6 practice nurses. Discussion guidelines on the topics to be investigated were provided to the moderator. Sessions were audio-recorded and transcribed verbatim. Thematic analysis was performed using the ATLAS-ti software. Results: The available operating systems and browsers and the lack of suitable spaces and time were reported as the main difficulties with the vCoP. The vCoP was perceived to be a flexible learning mode that provided up-to-date resources applicable to routine practice and offered a space for the exchange of experiences and approaches. Conclusions: The results from this pilot study show that the vCoP was considered useful for learning how to empower patients. However, while vCoPs have the potential to facilitate learning and as shown create professional awareness regarding patient empowerment, attention needs to be paid to technological and access issues and the time demands on professionals. We collected relevant inputs to improve the features, content and educational methods to be included in further vCoP implementation. Trial registration: ClinicalTrials.gov, NCT02757781. Registered on 25 April 2016.This study was financed by Instituto de Salud Carlos III and Cofinanced by Fondo Europeo de Desarrollo Regional (FEDER). Ministerio de Economía y Competitividad. Gobierno de España. (PI15/00164, PI15/00586, PI15/00566

    Acceptability and feasibility of a virtual community of practice to primary care professionals regarding patient empowerment : A qualitative pilot study

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    Background: Virtual communities of practice (vCoPs) facilitate online learning via the exchange of experiences and knowledge between interested participants. Compared to other communities, vCoPs need to overcome technological structures and specific barriers. Our objective was to pilot the acceptability and feasibility of a vCoP aimed at improving the attitudes of primary care professionals to the empowerment of patients with chronic conditions. Methods: We used a qualitative approach based on 2 focus groups: one composed of 6 general practitioners and the other of 6 practice nurses. Discussion guidelines on the topics to be investigated were provided to the moderator. Sessions were audio-recorded and transcribed verbatim. Thematic analysis was performed using the ATLAS-ti software. Results: The available operating systems and browsers and the lack of suitable spaces and time were reported as the main difficulties with the vCoP. The vCoP was perceived to be a flexible learning mode that provided up-to-date resources applicable to routine practice and offered a space for the exchange of experiences and approaches. Conclusions: The results from this pilot study show that the vCoP was considered useful for learning how to empower patients. However, while vCoPs have the potential to facilitate learning and as shown create professional awareness regarding patient empowerment, attention needs to be paid to technological and access issues and the time demands on professionals. We collected relevant inputs to improve the features, content and educational methods to be included in further vCoP implementation. Trial registration: ClinicalTrials.gov, NCT02757781. Registered on 25 April 2016

    Evaluating the Impact of Nature-Based Solutions: A Handbook for Practitioners

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    The Handbook aims to provide decision-makers with a comprehensive NBS impact assessment framework, and a robust set of indicators and methodologies to assess impacts of nature-based solutions across 12 societal challenge areas: Climate Resilience; Water Management; Natural and Climate Hazards; Green Space Management; Biodiversity; Air Quality; Place Regeneration; Knowledge and Social Capacity Building for Sustainable Urban Transformation; Participatory Planning and Governance; Social Justice and Social Cohesion; Health and Well-being; New Economic Opportunities and Green Jobs. Indicators have been developed collaboratively by representatives of 17 individual EU-funded NBS projects and collaborating institutions such as the EEA and JRC, as part of the European Taskforce for NBS Impact Assessment, with the four-fold objective of: serving as a reference for relevant EU policies and activities; orient urban practitioners in developing robust impact evaluation frameworks for nature-based solutions at different scales; expand upon the pioneering work of the EKLIPSE framework by providing a comprehensive set of indicators and methodologies; and build the European evidence base regarding NBS impacts. They reflect the state of the art in current scientific research on impacts of nature-based solutions and valid and standardized methods of assessment, as well as the state of play in urban implementation of evaluation frameworks

    Planck pre-launch status : The Planck mission

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    COVAD survey 2 long-term outcomes: unmet need and protocol

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    Vaccine hesitancy is considered a major barrier to achieving herd immunity against COVID-19. While multiple alternative and synergistic approaches including heterologous vaccination, booster doses, and antiviral drugs have been developed, equitable vaccine uptake remains the foremost strategy to manage pandemic. Although none of the currently approved vaccines are live-attenuated, several reports of disease flares, waning protection, and acute-onset syndromes have emerged as short-term adverse events after vaccination. Hence, scientific literature falls short when discussing potential long-term effects in vulnerable cohorts. The COVAD-2 survey follows on from the baseline COVAD-1 survey with the aim to collect patient-reported data on the long-term safety and tolerability of COVID-19 vaccines in immune modulation. The e-survey has been extensively pilot-tested and validated with translations into multiple languages. Anticipated results will help improve vaccination efforts and reduce the imminent risks of COVID-19 infection, especially in understudied vulnerable groups

    Role of the Gulf Stream and Kuroshio–Oyashio systems in large-scale atmosphere–ocean interaction : a review

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    Author Posting. © American Meteorological Society, 2010. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Climate 23 (2010): 3249-3281, doi:10.1175/2010JCLI3343.1.Ocean–atmosphere interaction over the Northern Hemisphere western boundary current (WBC) regions (i.e., the Gulf Stream, Kuroshio, Oyashio, and their extensions) is reviewed with an emphasis on their role in basin-scale climate variability. SST anomalies exhibit considerable variance on interannual to decadal time scales in these regions. Low-frequency SST variability is primarily driven by basin-scale wind stress curl variability via the oceanic Rossby wave adjustment of the gyre-scale circulation that modulates the latitude and strength of the WBC-related oceanic fronts. Rectification of the variability by mesoscale eddies, reemergence of the anomalies from the preceding winter, and tropical remote forcing also play important roles in driving and maintaining the low-frequency variability in these regions. In the Gulf Stream region, interaction with the deep western boundary current also likely influences the low-frequency variability. Surface heat fluxes damp the low-frequency SST anomalies over the WBC regions; thus, heat fluxes originate with heat anomalies in the ocean and have the potential to drive the overlying atmospheric circulation. While recent observational studies demonstrate a local atmospheric boundary layer response to WBC changes, the latter’s influence on the large-scale atmospheric circulation is still unclear. Nevertheless, heat and moisture fluxes from the WBCs into the atmosphere influence the mean state of the atmospheric circulation, including anchoring the latitude of the storm tracks to the WBCs. Furthermore, many climate models suggest that the large-scale atmospheric response to SST anomalies driven by ocean dynamics in WBC regions can be important in generating decadal climate variability. As a step toward bridging climate model results and observations, the degree of realism of the WBC in current climate model simulations is assessed. Finally, outstanding issues concerning ocean–atmosphere interaction in WBC regions and its impact on climate variability are discussed.Funding for LT was provided by the NASA-sponsored Ocean Surface Topography Science Team, under Contract 1267196 with the University of Washington, administered by the Jet Propulsion Laboratory. HN was supported in part by the Grant-in-Aid 18204044 by the Japan Society for Promotion for Science (JSPS) and the Global Environment Research Fund (S-5) of the Japanese Ministry of Environment. YK was supported by the Kerr Endowed Fund and Penzance Endowed Fund
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