| 1. |
- Ferrero, L., et al.
(författare)
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Determining the Aethalometer multiple scattering enhancement factor C from the filter loading parameter
- 2024
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Ingår i: Science of the Total Environment. - 0048-9697 .- 1879-1026. ; 917
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Tidskriftsartikel (refereegranskat)abstract
- Light-absorbing aerosols heat the atmosphere; an accurate quantification of their absorption coefficient is mandatory. However, standard reference instruments (CAPS, MAAP, PAX, PTAAM) are not always available at each measuring site around the world.By integrating all previous published studies concerning the Aethalometers, the AE33 filter loading parameter, provided by the dual-spot algorithm, were used to determine the multiple scattering enhancement factor from the Aethalometer itself (hereinafter CAE) on an yearly and a monthly basis. The method was developed in Milan, where Aethalometer measurements were compared with MAAP data; the comparison showed a good agreement in terms of equivalent black carbon (R2 = 0.93; slope = 1.02 and a negligible intercept = 0.12 μg m−3) leading to a yearly experimental multiple scattering enhancement factor of 2.51 ± 0.04 (hereinafter CMAAP). On a yearly time base the CAE values obtained using the new approach was 2.52 ± 0.01, corresponding to the experimental one (CMAAP). Considering the seasonal behavior, higher experimental CMAAP and computed CAE values were found in summer (2.83 ± 0.12) whereas, the lower ones in winter/early-spring (2.37 ± 0.03), in agreement with the single scattering albedo behavior in the Po Valley.Overall, the agreement between the experimental CMAAP and CAE showed a root mean squared error (RMSE) of just 0.038 on the CMAAP prediction, characterized by a slope close to 1 (1.001 ± 0.178), a negligible intercept (−0.002 ± 0.455) and a high degree of correlation (R2 = 0.955). From an environmental point of view, the application of a dynamic (space/time) determination of CAE increases the accuracy of the aerosol heating rate (compared to applying a fixed C value) up to 16 % solely in Milan, and to 114 % when applied in the Arctic at 80°N.
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| 2. |
- Reboli, T., et al.
(författare)
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Gas Turbine Combined Cycle Range Enhancer - Part 1 : Cyber-Physical Setup
- 2022
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Ingår i: Proceedings of the ASME Turbo Expo. - : ASME International.
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Konferensbidrag (refereegranskat)abstract
- Natural gas turbine combined cycles (GTCCs) are playing a fundamental role in the current energy transition phase towards sustainable power generation. The competitiveness of a GTCC in future electrical networks will thus be firmly related to its capability of successfully compensating the discontinuous power demands. This can be made possible by enhancing power generation flexibility and extending the operative range of the plant. To achieve this goal, a test rig to investigate gas turbine inlet conditioning techniques was developed at the TPG laboratory of the University of Genoa, Italy. The plant is composed of three key hardware components: a micro gas turbine, a butane-based heat pump, and a phase-change material cold thermal energy storage system. The physical test-rig is virtually scaled up through a cyber-physical approach, to emulate a full scale integrated system. The day-ahead schedule of the plant is determined by a high-level controller referring to the Italian energy market, considering fluctuations in power demands. By using HP and TES, it is possible to control the mGT inlet air temperature and thus enhance the operational range of the plant optimizing the management of energy flows. This article (Part 1) introduces the new experimental facility, the real-time bottoming cycle dynamic model, and the four-level control system that regulates the operation of the whole cyber-physical plant. The experimental campaign and the analysis of the system performance are presented in the Part 2.
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| 3. |
- Braae, Ellen, et al.
(författare)
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A conversation on education
- 2018
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Ingår i: Routledge Research Companion to Landscape Architecture. - : Routledge. ; , s. 324-334
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Landscape architecture today is becoming increasingly professionalized as a quasi-global profession—not least through the successful expansion of academic research efforts within the discipline. This includes the kinds of effort to which this volume as a whole contributes, and this chapter broadens our understanding of the institutional structures within which we operate. Indeed, education may be one of the most important realms for the engagement and transmission of knowledge that moves back and forth and connects practice and research in intricate ways—with the added benefit that education remains a dialogical and personal setting for exchange, not least in studio-driven design programmes. We therefore have asked significant educators from Landscape Architecture programmes in Europe and North America to reflect on the tensions and challenges the profession currently faces, and on what we can do to prepare new generations of landscape architects who are now part of the educational system or will be so in the future. Moreover, we wished to inspire a discussion of how the aesthetic and ethical dimensions of landscape architecture potentially impact on the discipline, and of the role they should play in future landscape architecture education.
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| 4. |
- Gini, L., et al.
(författare)
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Part-Load Behaviour And Control Philosophy Of A Recuperated Supercritical Co2Cycle
- 2022
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Ingår i: Proceedings of the ASME Turbo Expo. - : American Society of Mechanical Engineers (ASME).
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Konferensbidrag (refereegranskat)abstract
- High efficiency, flexibility and competitive capital costs make supercritical CO2 (sCO2) systems a promising technology for renewable power generation in a low carbon energy scenario. Recently, innovative supercritical systems have been studied in the literature and proposed by DOE-NETL (STEP project) and a few projects in the EU Horizon 2020 program aiming to demonstrate supercritical CO2 Brayton power plants, promising superior techno-economic features than steam cycles particularly at high temperatures. The H2020 SOLARSCO2OL project1, which started in 2020, is building the first European MW-scale sCO2 demonstration plant and has been specifically tailored for Concentrating Solar Power (CSP) applications. This paper presents the first offdesign analysis of such a demonstrator, which is based on a simply recuperated sCO2 cycle. The part-load analysis ranged from 50% of nominal up to a 105% peak load, discussing the impact on compressor and turbine operating conditions. The whole system dynamic model has been developed in TRANSEO MATLAB® environment. Full operational envelop has been determined considering cycle main constraints, such as maximum turbine inlet temperature and minimum pressure at compressor inlet. The off-design performance analysis highlights the most relevant relationships among the main part-load regulating parameters, namely mass flow rate, total mass in the loop, and available heat source. The results show specific features of different control approaches, discussing the pros and cons of each solution, considering also its upscale towards commercial applications. In particular, the analysis shows that at 51% of load an efficiency decrease of 20% is expected.
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| 5. |
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| 6. |
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| 7. |
- Mayer, Ludovic, et al.
(författare)
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Widespread Pesticide Distribution in the European Atmosphere Questions their Degradability in Air
- 2024
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Ingår i: Environmental Science and Technology. - 0013-936X. ; 58:7, s. 3342-3352
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Tidskriftsartikel (refereegranskat)abstract
- Risk assessment of pesticide impacts on remote ecosystems makes use of model-estimated degradation in air. Recent studies suggest these degradation rates to be overestimated, questioning current pesticide regulation. Here, we investigated the concentrations of 76 pesticides in Europe at 29 rural, coastal, mountain, and polar sites during the agricultural application season. Overall, 58 pesticides were observed in the European atmosphere. Low spatial variation of 7 pesticides suggests continental-scale atmospheric dispersal. Based on concentrations in free tropospheric air and at Arctic sites, 22 pesticides were identified to be prone to long-range atmospheric transport, which included 15 substances approved for agricultural use in Europe and 7 banned ones. Comparison between concentrations at remote sites and those found at pesticide source areas suggests long atmospheric lifetimes of atrazine, cyprodinil, spiroxamine, tebuconazole, terbuthylazine, and thiacloprid. In general, our findings suggest that atmospheric transport and persistence of pesticides have been underestimated and that their risk assessment needs to be improved.
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