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Abstract Secondary concentrators are used in solar concentrating systems to redirect solar beams reflected by the primary concentrators to the focal point or line. These components allow to increase the concentrated solar flux density and hence to lower thermal radiation losses. Solar reflectors for secondary concentrators are permanently exposed to environmental conditions, high radiation fluxes and elevated temperatures that potentially cause stress and degradation throughout the time. Therefore, analyzing solar reflectors of secondary concentrators by simulating these conditions is crucial. No previous research works about the durability of solar reflector materials for secondary concentrators have been reported. The present work is focused on studying the degradation of the reflector materials by simulating accelerated aging, caused by several ambient parameters and the effect of concentrated radiation. Both cooled and uncooled systems for secondary concentrators are included in this study. According to results obtained, aluminum reflectors and thin silvered-glass reflectors glued to an aluminum structure showed minimum reflectance losses and structural degradation under the operation conditions of cooled 3D secondary concentrators (tower systems). Following critical aspects to avoid reflector degradation were identified: to select a suitable adhesive material to glue the thin silvered-glass reflector to the support aluminum structure, to properly protect reflectors edges, to design a suitable cooling system and to avoid the combination of high radiation fluxes with mechanical stress. In addition, laminated silvered-glass reflectors have shown to be suitable for uncooled 2D secondary concentrators (Fresnel collectors). Furthermore, a comparison with naturally aged secondary concentrators using silvered-glass reflectors glued to an aluminum structure revealed that the simulated degradation under accelerated conditions performed in this work did reproduce the most frequent degradation patterns suffered in real operating conditions.

Results from a literature review of hybrid life-cycle assessment. Details the underestimation of purely process-based life-cycle assessment and the diversity in terminology used by authors.

Dataset abstract This dataset contains quality-checked meteorological observations of air temperature, relative humidity, dew point, barometric pressure and observations of downwelling solar radiation and ultraviolet radiation. Further it contains the wind speed and direction relative to the ship but not corrected for air-flow distortion, and translated into the earth reference frame. For each of these variables observations are available from a portside and starboard side sensor. The dataset also contains, cloud base height and sky cover at three levels measured with a Ceilometer. As additional information the solar azimuth and altitude angle have been calculated for the ship’s position every five minutes and have been added as a one-minute time series using the nearest value. The ship’s position, heading, course and speed over ground are also provided. The wind speed measurements were made at a height of approximately 30.5 meters above sea level. The measurement height of the temperature and humidity probes is 23.7 meters above sea level. The barometric pressure was measured at 20 meters above sea level. The observations have been screened for implausible values and on some occasions despiking based on visual inspection and a rolling interquartile range filter have been applied. Solar radiation measurements are affected by shadowing of the ship, and the air temperature and humidity by the heating of air that passes over the ship. Masks are provided to flag affected observations. The wind speed readings are affected by airflow distortion and should be used with consideration until a dataset of corrected wind speeds is published. More details on airflow distortion can be requested from the contact person. Dataset contents ACE_filtered_meteorological_data_1min.csv, data file, comma-separated values diff_TA1_TA3_WDR2_5min_1.png, metadata, portable network graphics ratio_SR1_SR3_solangle_5min_1.png, metadata, portable network graphics data_file_header.txt, metadata, text README.txt, metadata, text ace_filtered_meteorological_data_change_log.txt, metadata, text Change log v1.1 - The range check for skycover (SC) and cloudlevel (CL) was added to the quality-checking routines. 53 data points violated the range check for these variables: these have now been marked as NaN. v1.0 - Initial release of verified meteorological data. Dataset license This meteorological dataset is made available under the Creative Commons Attribution 4.0 International License (CC BY 4.0) whose full description can be found at https://creativecommons.org/licenses/by/4.0/ {"references": ["Smith, Shawn R., Mark A. Bourassa, and Ryan J. Sharp. Establishing More Truth in True Winds. JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY 16 (1999): 14.", "Stull, Roland. Wet-Bulb Temperature from Relative Humidity and Air Temperature. 2011. Journal of Applied Meteorology and Climatology 50, no. 11 (9 September 2011): 2267\u201369. https://doi.org/10.1175/JAMC-D-11-0143.1."]} The Antarctic Circumnavigation Expedition was made possible by funding from the Swiss Polar Institute and Ferring Pharmaceuticals. Antarctic Circumnavigation Expedition – Delivering Added value To Antarctica (ACE-DATA) is funded by the Swiss Data Science Center as Project number 17-02.

Abstract Within the broader context of energy security and critical infrastructure protection, the comprehensive assessment of accidents and their related consequences are of high priority for many stakeholders. The risk of accidents is commonly assessed by aggregated risk indicators, allowing for a consistent and direct comparison between energy chains and country groups. However, these indicators do not explicitly evaluate consequences at selected probability levels and/or consider risk aversion aspects. Furthermore, in risk-informed decision-making it is important to account for risk preferences of different stakeholders. To overcome these potential drawbacks, in this study, Value-at-Risk, Expected Shortfall and the Spectral Risk Measures, which are commonly used in the financial realm, are applied within an energy security perspective. In particular, fatality risk indicators are calculated for different country groups of three fossil data sets (coal, oil, natural gas) extracted from the Energy-related Severe Accident Database (ENSAD). The use of these risk measures facilitates a direct comparison and a better understanding of energy accident risks to insurers and other industry stakeholders that normally focus on financial and less infrastructure-related aspects. Furthermore, the usefulness of the risk measures and their pros and cons in the evaluation of accident risks in the energy sector has been discussed.

Abstract A new model, primarily aimed at air oxidation has been recently developed at PSI, assessed against separate effects tests data and implemented into a developmental version of RELAP5/SCDAPSIM. Oxygen is treated as an active species and nitrogen as a catalyst that promotes breakaway, so that the essential feature of the model is the transition from parabolic to breakaway oxidation. As part of the second stage of the model assessment, analysis is performed of the air ingress bundle experiment PARAMETER-SF4 which comprised pre-oxidation in steam, a period of air ingress, and reflood. The analysis focuses on the thermal response and possible breakaway during, the oxygen consumption. Of particular interest is the effect of oxygen starvation on the oxidation excursion during the subsequent reflood.

Abstract The purification of upgraded metallurgical silicon by extraction of boron and phosphorus was experimentally demonstrated using concentrated solar radiation in the temperature range 1550–1700 °C. The process operated with a flow of Ar at reduced pressure (0.05 atm) for elimination of P, and with a flow of H 2 O for elimination of B. Impurity content decreased by a factor of 3 after a 50-min solar treatment, yielding Si samples with final average content of 2.1 ppm w B and 3.2 ppm w P.

Abstract This paper presents the results of a series of studies, using detailed pin power distributions derived from Monte Carlo simulation results, to assess the effects of local dryout during normal operation on the cladding temperatures, heat fluxes and potentially on cladding oxidation for modern boiling water reactor (BWR) fuel. The development of a new three-dimensional LWR fuel thermo-mechanics solver, OpenFoam Fuel BEhAviour Tool (OFFBEAT), was initiated for these studies. Three-dimensional simulations of heat transfer in an axial section of a fuel pin have been conducted using OFFBEAT assuming different local dryout conditions. The results have shown that local power effects and, in particular, strong power gradients across the fuel pin can contribute significantly towards increased heat fluxes in the cladding, reducing the safety margin to dryout. Further, the studies have shown that, under the conservative assumption that the fuel pellet is not centred, but is instead touching the cladding on one side, the safety margin is further decreased. Investigations of possible neutronics feedback effects following dryout, taking into account the detailed intra-pin temperature distribution before and after dryout, have confirmed that there is no mitigating neutronics effect under dryout conditions. Finally, a basic study of the cladding oxidation under dryout conditions has shown that days to weeks of continuous dryout, or alternatively weeks of repeated dryout and rewetting would be required to obtain oxide layers thicknesses that would affect the mechanical integrity of the cladding. This work is an initial step towards developing a comprehensive multi-physics capability for simulations and studies of local three-dimensional coupled effects during dryout, and on this basis strengthen our understanding of the potential impact on the cladding integrity.