55 research outputs found
Automatic detection of PV systems failures from monitoring validated on 10,000 BIPV systems in Europe
The installers and owners show a growing interest in the follow-up of the performance of their photovoltaic (PV) systems. The owners are requesting reliable sources of information to ensure that their system is functioning properly, and the installers are actively looking for efficient ways of providing them the most useful possible information from the data available. Policy makers are becoming increasingly interested in the knowledge of the real performance of PV systems and the most frequent sources of problems that they suffer to be able to target the identified challenges properly. The scientific and industrial PV community is also requiring an access to massive operational data to pursue the technological improvements further
An open-source simulation tool of grid-connected PV systems.
This paper will present an open-source simulation tool, which is being developed in the
frame of an European research project1. The tool, whose final version will be freely available
through a website, allows the modelling and the design of different types of grid-connected
PV systems, such as large grid-connected plants and building-integrated installations.
The tool is based on previous software developed by the IES-UPM2, whose models and
energy losses scenarios have been validated in the commissioning of PV projects3 carried out
in Spain, Portugal, France and Italy, whose aggregated capacity is nearly 300MW. This link
between design and commissioning is one of the key points of tool presented here, which is
not usually addressed by present commercial software.
The tool provides, among other simulation results, the energy yield, the analysis and
breakdown of energy losses, and the estimations of financial returns adapted to the legal and
financial frameworks of each European country. Besides, educational facilities will be
developed and integrated in the tool, not only devoted to learn how to use this software, but
also to train the users on the best design PV systems practices.
The tool will also include the recommendation of several PV community experts, which
have been invited to identify present necessities in the field of PV systems simulation. For
example, the possibility of using meteorological forecasts as input data, or modelling the
integration of large energy storage systems, such as vanadium redox or lithium-ion batteries.
Finally, it is worth mentioning that during the verification and testing stages of this
software development, it will be also open to the suggestions received from the different
actors of the PV community, such as promoters, installers, consultants, etc
Tools for the high penetration of PV Systems in the EU electrical networks: results of PVCROPS Project
The Solar Energy Industrial Initiative established the objective of integrating PV into the grid to provide up to 12% of the EU electricity demand. The FP7 project PVCROPS has developed solutions to allow the high penetration of PV systems in EU electrical networks and to reduce its Levelized Cost (LCoE) increasing PV system performance. The solutions consist of documents like technical specifications and toolboxes for design, prediction, integration of batteries and automatic detection of performance failures. Six of them are on-line free tools and thirteen are marketable products. These tools allow reducing the LCoE up to 30%, increasing the Performance Ratio up to 9% and PV penetration of 30%. The tools developed by PVCROPS are detailed in www.pvcrops.e
The FlözerbÀndli: A Late Palaeolithic/ Early Mesolithic Site in the Muota Valley (Canton Schwyz/ CH)
Evolving the Physical Global Ocean Observing System for Research and Application Services Through International Coordination
Climate change and variability are major societal challenges, and the ocean is an integral part of this complex and variable system. Key to the understanding of the ocean's role in the Earth's climate system is the study of ocean and sea-ice physical processes, including its interactions with the atmosphere, cryosphere, land and biosphere. These processes include those linked to ocean circulation; the storage and redistribution of heat, carbon, salt and other water properties; and air-sea exchanges of heat, momentum, freshwater, carbon and other gasses. Measurements of ocean physics variables are fundamental to reliable earth prediction systems for a range of applications and users. In addition, knowledge of the physical environment is fundamental to growing understanding of the ocean's biogeochemistry and biological/ecosystem variability and function. Through the progress from OceanObs'99 to OceanObs'09, the ocean observing system has evolved from a platform centric perspective to an integrated observing system. The challenge now is for the observing system to evolve to respond to an increasingly diverse end user group. The Ocean Observations Physics and Climate panel (OOPC), formed in 1995, has undertaken many activities that led to observing system-related agreements. Here, OOPC will explore the opportunities and challenges for the development of a fit-for-purpose, sustained and prioritized ocean observing system, focusing on physical variables that maximize support for fundamental research, climate monitoring, forecasting on different timescales, and society. OOPC recommendations are guided by the Framework for Ocean Observing (Lindstrom et al. 2012) which emphasizes identifying user requirements by considering time and space scales of the Essential Ocean Variables. This approach provides a framework for reviewing the adequacy of the observing system, looking for synergies in delivering an integrated observing system for a range of applications and focusing innovation in areas where existing technologies do not meet these requirement
4U 1907+09: a HMXB running away from the Galactic plane
We report the discovery of a bow shock around the high-mass X-ray binary
(HMXB) 4U 1907+09 using the Spitzer Space Telescope 24 m data (after Vela
X-1 the second example of bow shocks associated with HMXBs). The detection of
the bow shock implies that 4U 1907+09 is moving through the space with a high
(supersonic) peculiar velocity. To confirm the runaway nature of 4U 1907+09, we
measured its proper motion, which for an adopted distance to the system of 4
kpc corresponds to a peculiar transverse velocity of km/s,
meaning that 4U 1907+09 is indeed a runaway system and supporting the general
belief that most of HMXBs possess high space velocities. The direction of
motion of 4U 1907+09 inferred from the proper motion measurement is consistent
with the orientation of the symmetry axis of the bow shock, and shows that the
HMXB is running away from the Galactic plane. We also present the Spitzer
images of the bow shock around Vela X-1 (a system similar to 4U 1907+09) and
compare it with the bow shock generated by 4U 1907+09.Comment: accepted for publication in A&
Altimetry for the future: Building on 25 years of progress
In 2018 we celebrated 25 years of development of radar altimetry, and the progress achieved by this methodology in the fields of global and coastal oceanography, hydrology, geodesy and cryospheric sciences. Many symbolic major events have celebrated these developments, e.g., in Venice, Italy, the 15th (2006) and 20th (2012) years of progress and more recently, in 2018, in Ponta Delgada, Portugal, 25 Years of Progress in Radar Altimetry. On this latter occasion it was decided to collect contributions of scientists, engineers and managers involved in the worldwide altimetry community to depict the state of altimetry and propose recommendations for the altimetry of the future. This paper summarizes contributions and recommendations that were collected and provides guidance for future mission design, research activities, and sustainable operational radar altimetry data exploitation. Recommendations provided are fundamental for optimizing further scientific and operational advances of oceanographic observations by altimetry, including requirements for spatial and temporal resolution of altimetric measurements, their accuracy and continuity. There are also new challenges and new openings mentioned in the paper that are particularly crucial for observations at higher latitudes, for coastal oceanography, for cryospheric studies and for hydrology. The paper starts with a general introduction followed by a section on Earth System Science including Ocean Dynamics, Sea Level, the Coastal Ocean, Hydrology, the Cryosphere and Polar Oceans and the ââGreenâ Ocean, extending the frontier from biogeochemistry to marine ecology. Applications are described in a subsequent section, which covers Operational Oceanography, Weather, Hurricane Wave and Wind Forecasting, Climate projection. Instrumentsâ development and satellite missionsâ evolutions are described in a fourth section. A fifth section covers the key observations that altimeters provide and their potential complements, from other Earth observation measurements to in situ data. Section 6 identifies the data and methods and provides some accuracy and resolution requirements for the wet tropospheric correction, the orbit and other geodetic requirements, the Mean Sea Surface, Geoid and Mean Dynamic Topography, Calibration and Validation, data accuracy, data access and handling (including the DUACS system). Section 7 brings a transversal view on scales, integration, artificial intelligence, and capacity building (education and training). Section 8 reviews the programmatic issues followed by a conclusion
Mortality and pulmonary complications in patients undergoing surgery with perioperative SARS-CoV-2 infection: an international cohort study
Background: The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on postoperative recovery needs to be understood to inform clinical decision making during and after the COVID-19 pandemic. This study reports 30-day mortality and pulmonary complication rates in patients with perioperative SARS-CoV-2 infection. Methods: This international, multicentre, cohort study at 235 hospitals in 24 countries included all patients undergoing surgery who had SARS-CoV-2 infection confirmed within 7 days before or 30 days after surgery. The primary outcome measure was 30-day postoperative mortality and was assessed in all enrolled patients. The main secondary outcome measure was pulmonary complications, defined as pneumonia, acute respiratory distress syndrome, or unexpected postoperative ventilation. Findings: This analysis includes 1128 patients who had surgery between Jan 1 and March 31, 2020, of whom 835 (74·0%) had emergency surgery and 280 (24·8%) had elective surgery. SARS-CoV-2 infection was confirmed preoperatively in 294 (26·1%) patients. 30-day mortality was 23·8% (268 of 1128). Pulmonary complications occurred in 577 (51·2%) of 1128 patients; 30-day mortality in these patients was 38·0% (219 of 577), accounting for 81·7% (219 of 268) of all deaths. In adjusted analyses, 30-day mortality was associated with male sex (odds ratio 1·75 [95% CI 1·28â2·40], p\textless0·0001), age 70 years or older versus younger than 70 years (2·30 [1·65â3·22], p\textless0·0001), American Society of Anesthesiologists grades 3â5 versus grades 1â2 (2·35 [1·57â3·53], p\textless0·0001), malignant versus benign or obstetric diagnosis (1·55 [1·01â2·39], p=0·046), emergency versus elective surgery (1·67 [1·06â2·63], p=0·026), and major versus minor surgery (1·52 [1·01â2·31], p=0·047). Interpretation: Postoperative pulmonary complications occur in half of patients with perioperative SARS-CoV-2 infection and are associated with high mortality. Thresholds for surgery during the COVID-19 pandemic should be higher than during normal practice, particularly in men aged 70 years and older. Consideration should be given for postponing non-urgent procedures and promoting non-operative treatment to delay or avoid the need for surgery. Funding: National Institute for Health Research (NIHR), Association of Coloproctology of Great Britain and Ireland, Bowel and Cancer Research, Bowel Disease Research Foundation, Association of Upper Gastrointestinal Surgeons, British Association of Surgical Oncology, British Gynaecological Cancer Society, European Society of Coloproctology, NIHR Academy, Sarcoma UK, Vascular Society for Great Britain and Ireland, and Yorkshire Cancer Research
Outcomes from elective colorectal cancer surgery during the SARS-CoV-2 pandemic
This study aimed to describe the change in surgical practice and the impact of SARS-CoV-2 on mortality after surgical resection of colorectal cancer during the initial phases of the SARS-CoV-2 pandemic
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