6,468 research outputs found

    THROES: a caTalogue of HeRschel Observations of Evolved Stars. I. PACS range spectroscopy

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    This is the first of a series of papers presenting the THROES (A caTalogue of HeRschel Observations of Evolved Stars) project, intended to provide a comprehensive overview of the spectroscopic results obtained in the far-infrared (55-670 microns) with the Her- schel space observatory on low-to-intermediate mass evolved stars in our Galaxy. Here we introduce the catalogue of interactively reprocessed PACS (Photoconductor Array Camera and Spectrometer) spectra covering the 55-200 microns range for 114 stars in this category for which PACS range spectroscopic data is available in the Herschel Science Archive (HSA). Our sample includes objects spanning a range of evolutionary stages, from the asymptotic giant branch to the planetary nebula phase, displaying a wide variety of chemical and physical properties. The THROES/PACS catalogue is accessible via a dedicated web-based inter- face (https://throes.cab.inta-csic.es/) and includes not only the science-ready Herschel spectroscopic data for each source, but also complementary photometric and spectroscopic data from other infrared observatories, namely IRAS (Infrared Astronomical Satellite), ISO (Infrared Space Observatory) or AKARI, at overlapping wavelengths. Our goal is to create a legacy-value Herschel dataset that can be used by the scientific community in the future to deepen our knowledge and understanding of these latest stages of the evolution of low-to-intermediate mass stars.Comment: 38 page

    Smart Demand for Improving Short-term Voltage Control on Distribution Networks

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    Smart grids must involve active roles from end users in order to be truly smart. The energy consumption has to be done in a flexible and intelligent manner, in accordance with the current conditions of the power system. Moreover, with the advent of dispersed and renewable generation, increasing customer integration to aid power system performance is almost inevitable. This study introduces a new type of smart demand side technology, denoted demand as voltage controlled reserve (DVR), to improve short-term voltage control, where customers are expected to play a more dynamic role to improve voltage control. The technology can be provided by thermostatically controlled loads as well as other types of load. This technology is proven to be effective in case of distribution systems with a large composition of induction motors, where the voltage presents a slow recovery characteristic due to deceleration of the motors during faults. This study presents detailed models, discussion and simulation tests to demonstrate the technical viability and effectiveness of the DVR technology for short-term voltage control.3872473

    Strength assessment of Al-Humic and Al-Kaolin aggregates by intrusive and non-intrusive methods

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    Made available in DSpace on 2019-10-06T15:34:15Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-06-15Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Resistance to breakage is a critical property of aggregates generated in water and wastewater treatment processes. After flocculation, aggregates should ideally keep their physical characteristics (i.e. size and morphology), to result in the best performance possible by individual separation processes. The integrity of aggregates after flocculation depends upon their capacity to resist shear forces while transported through canals, passages, apertures, orifices and other hydraulic units. In this study, the strength of Al-Humic and Al-Kaolin aggregates was investigated using two macroscopic measurement techniques, based on both intrusive and non-intrusive methods, using image analysis and light scattering based equipment. Each technique generates different information which was used for obtaining three floc strength indicators, namely, strength factor (SF), local stress from the hydrodynamic disturbance (σ) and the force coefficient (γ) for two different study waters. The results showed an increasing trend for the SF of both Al-Humic and Al-Kaolin aggregates, ranging from 29.7% to 78.6% and from 33.3% to 85.2%, respectively, in response to the increase of applied shear forces during flocculation (from 20 to 120 s−1). This indicates that aggregates formed at higher shear rates are more resistant to breakage than those formed at lower rates. In these conditions, σ values were observed to range from 0.07 to 0.44 N/m2 and from 0.08 to 0.47 N/m2 for Al-Humic and Al-Kaolin, respectively. Additionally, it was found that for all studied conditions, the resistance of aggregates to shear forces was nearly the same for Al-Humic and Al-Kaolin aggregates, formed from destabilized particles using sweep coagulation. These results suggest that aggregate strength may be mainly controlled by the coagulant, emphasizing the importance of the coagulant selection in water treatment. In addition, the use of both intrusive and non-intrusive techniques helped to confirm and expand previous experiments recently reported in literature.Instituto de Geociências e Ciências Exatas Univ. Estadual Paulista (UNESP), Av. 24-A, 1515, Jardim Bela Vista, Rio ClaroPrograma de Pós-graduação em Engenharia Civil e Ambiental Univ. Estadual Paulista (UNESP), Av. 24-A, 1515, Jardim Bela Vista, Rio ClaroDepartment of Civil Engineering University of BirminghamDepartment of Civil Environmental and Geomatic Engineering University College London, Gower StInstituto de Geociências e Ciências Exatas Univ. Estadual Paulista (UNESP), Av. 24-A, 1515, Jardim Bela Vista, Rio ClaroPrograma de Pós-graduação em Engenharia Civil e Ambiental Univ. Estadual Paulista (UNESP), Av. 24-A, 1515, Jardim Bela Vista, Rio ClaroFAPESP: 2017/19195-

    Productivity of three sugarcane cultivars under dry and drip irrigated management

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    O objetivo neste trabalho foi estudar o efeito da tecnologia de irrigação por gotejamento, em cultivares de cana-de-açúcar, em dois ciclos de produção (cana-planta e cana-soca). O delineamento experimental utilizado foi o de blocos ao acaso, com quatro repetições, constituídos pela combinação de três cultivares de cana-de-açúcar: RB867515; RB855536 e SP80-3280, e dois manejos da cultura: sistema de irrigação por gotejamento subterrâneo e sistema de sequeiro, totalizando seis tratamentos. O primeiro ciclo teve duração de 336 dias, ocorrendo precipitação de 1.480 mm. O volume de água disponibilizado pelo sistema de irrigação por gotejamento foi de 400 mm, totalizando 1.880 mm. O segundo ciclo teve duração de 365 dias, cujo volume de água por meio de precipitação foi de 1.394 mm; somados aos 320 mm fornecidos pelo sistema de irrigação, totalizaram 1.714 mm. Ocorreu interação entre manejo e cultivar para as variáveis: produtividade de colmos (TCH) e produtividade de açúcar (TPH) em que a maior diferença foi observada para a cultivar SP80-3280. As cultivares apresentaram respostas diferenciadas na eficiência de utilização da água. No manejo irrigado por gotejamento houve elevação de 24% na produtividade de colmos e de 23% na produtividade de açúcar, em relação ao manejo de sequeiro.This study aimed to evaluate the effect of drip irrigation technology in different sugarcane varieties in two crop cycles (plant cane and ratoon). The experimental design was in completly randomized blocks, in split-plot with four replications, constituted by three sugarcane genotypes: RB867515; RB855536 and SP80-3280 and two crop management: drip irrigation system and rainfed system, totalizing six treatments. The first cycle lasted for 336 days, with rainfall of 1,480 mm. The volume of water provided by the system of drip irrigation was 400 mm, totaling 1,880 mm. The second cycle lasted for 365 days, the volume of water through rainfall was 1,394 mm, added to 320 mm provided by the system of irrigation, totaled 1,714 mm. Interaction between management and cultivars was found significant for the variables: productivity of stalks (TCH) and sugar yield (TPH), in which the largest difference was observed for cultivar SP80-3280. There was significant response to drip irrigation, on average the increase of production of stalks and sugar was 24 and 23%, respectively

    Both cetaceans in the Brazilian Amazon show sustained, profound population declines over two decades

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    <div><p>Obligate river dolphins occur only in the rivers of Asia and South America, where they are increasingly subject to damaging pressures such as habitat degradation, food competition and entanglement in fishing gear as human populations expand. The Amazon basin hosts two, very different, dolphins—the boto or Amazon river dolphin (<i>Inia geoffrensis</i>) and the smaller tucuxi (<i>Sotalia fluviatilis</i>). Both species have wide geographical ranges and were once considered to be relatively abundant. Their IUCN Red List conservation status of Data Deficient (DD), due to limited information on threats, ecology, population numbers and trends, did not initially cause alarm. However, the development of dolphin hunting to provide fish bait at around the beginning of this millennium broadly coincided with the onset of a widespread perception that numbers of both species were in decline. Consequently, the need for population trend data to inform conservation advice and measures became urgent. This paper presents a 22-year time series of standardised surveys for both dolphins within the Mamirauá Reserve, Amazonas State, Brazil. Analysis of these data show that both species are in steep decline, with their populations halving every 10 years (botos) and 9 years (tucuxis) at current rates. These results are consistent with published, independent information on survival rates of botos in this area, which demonstrated a substantial drop in annual survival, commencing at around the year 2000. Mamirauá is a protected area, and is subject to fewer environmental pressures than elsewhere in the region, so there is no reason to suspect that the decline in dolphins within the Reserve is more pronounced than outside it. If South America's freshwater cetaceans are to avoid following their Asian counterparts on the path to a perilous conservation status, effective conservation measures are required immediately. Enforcement of existing fishery laws would greatly assist in achieving this.</p></div

    Excited states of bromopyrimidines probed by vuv photoabsorption spectroscopy and theoretical calculations

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    Funding Information: Funding: J.P.‐d.‐S. acknowledges the Portuguese National Funding Agency FCT‐MCTES through PhD grant PD/BD/142768/2018, together with R.R., J.A., M.M. and F.F.d.S. through the researcher grant PTDC/FIS‐AQM/31215/2017 and AIL through the researcher grant PTDC/FIS‐ AQM/31281/2017. This work was also supported by Radiation Biology and Biophysics Doctoral Training Programme (RaBBiT, PD/00193/2012); UIDB/04378/2020 (UCIBIO); and UIDB/00068/2020 (CEFITEC). The research leading to this result has been supported by the project CALIPSOplus under the Grant Agreement 730872 from the EU Framework Programme for Research and Innovation HORIZON 2020.We report absolute photoabsorption cross sections for gas‐phase 2‐ and 5‐ bromopyrimidine in the 3.7–10.8 eV energy range, in a joint theoretical and experimental study. The measurements were carried out using high‐resolution vacuum ultraviolet synchrotron radiation, with quantum chemical calculations performed through the nuclear ensemble approach in combination with time‐dependent density functional theory, along with additional Franck–Condon Herzberg–Teller calculations for the first absorption band (3.7–4.6 eV). The cross sections of both bromopyrimidines are very similar below 7.3 eV, deviating more substantially from each other at higher energies. In the 7.3–9.0 eV range where the maximum cross‐section is found, a single and broad band is observed for 5‐bromopyrimidine, while more discernible features appear in the case of 2‐bromopyrimidine. Several π* ← π transitions account for the most intense bands, while weaker ones are assigned to transitions involving the nitrogen and bromine lone pairs, the antibonding σ*Br orbital, and the lower‐lying Rydberg states. A detailed comparison with the available photo‐absorption data of bromobenzene is also reported. We have found significant differences regarding the main absorption band, which is more peaked in bromobenzene, becoming broader and shifting to higher energies in both bromopyrimidines. In addition, there is a significant suppression of vibrational structures and of Rydberg states in the pair of isomers, most noticeably for 2‐bromopyrimidine.publishersversionpublishe

    DESiRED -- Dynamic, Enhanced, and Smart iRED: A P4-AQM with Deep Reinforcement Learning and In-band Network Telemetry

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    Active Queue Management (AQM) is a mechanism employed to alleviate transient congestion in network device buffers, such as routers and switches. Traditional AQM algorithms use fixed thresholds, like target delay or queue occupancy, to compute random packet drop probabilities. A very small target delay can increase packet losses and reduce link utilization, while a large target delay may increase queueing delays while lowering drop probability. Due to dynamic network traffic characteristics, where traffic fluctuations can lead to significant queue variations, maintaining a fixed threshold AQM may not suit all applications. Consequently, we explore the question: \textit{What is the ideal threshold (target delay) for AQMs?} In this work, we introduce DESiRED (Dynamic, Enhanced, and Smart iRED), a P4-based AQM that leverages precise network feedback from In-band Network Telemetry (INT) to feed a Deep Reinforcement Learning (DRL) model. This model dynamically adjusts the target delay based on rewards that maximize application Quality of Service (QoS). We evaluate DESiRED in a realistic P4-based test environment running an MPEG-DASH service. Our findings demonstrate up to a 90x reduction in video stall and a 42x increase in high-resolution video playback quality when the target delay is adjusted dynamically by DESiRED.Comment: Preprint (Computer Networks under review
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