2,471 research outputs found

    Recycled versus non-recycled insulation alternatives: LCA analysis for different climatic conditions in Spain

    Full text link
    [EN] The construction sector represents more than 40% of energy consumption in the European Union, as well as one of the biggest causes of environmental impact. Therefore, this sector needs a great deal of intervention through policies that promote the energetic efficiency of the buildings. One of the most important structural components to reach this energetic efficiency is the facades. In this work, the facade ventilated is chosen due to its better thermal insulation behaviour. The environmental impact of the facade ventilated depends on the thermal insulation material. The goal of this paper is to evaluate the environmental impact of different ventilated facades according to their thermal insulation behavior. For this purpose, the life-cycle assessment is applied in ventilated facades with different materials in different locations. The materials studied are the rock wool, the natural cork and the recycled cork, and the locations considered are the different climatic areas of Spain. To reach a complete environmental assessment all the ventilated facades life-cycle is considered, from cradle to grave. To do this we use the Open LCA software with the Ecoinvent database with the ReCiPe method. The results show that the recycled cork is the thermal insulation with the lowest environmental impact regardless the location.The authors acknowledge the financial support of the Spanish Ministry of Economy and Business (Project: BIA2017-85098-R) and the Spanish Ministry of Science and Innovation (Project: PID2020-117056RB-I00), along with FEDER funding. In addition would also acknowledge the Spanish Ministry of Science, Innovation and Universities for David Martinez-Munoz University Teacher Training Grant (FPU-18/01592).Ata-Ali, N.; Penadés-Plà, V.; Martínez-Muñoz, D.; Yepes, V. (2021). Recycled versus non-recycled insulation alternatives: LCA analysis for different climatic conditions in Spain. Resources Conservation and Recycling. 175:1-8. https://doi.org/10.1016/j.resconrec.2021.105838S1817

    Fabrication of integrated planar gunn diode and micro-cooler on GaAs substrate

    Get PDF
    We demonstrate fabrication of an integrated micro cooler with the planar Gunn diode and characterise its performance. First experimental results have shown a small cooling at the surface of the micro cooler. This is first demonstration of an integrated micro-cooler with a planar Gunn diode

    WIYN Open Cluster Study XI: WIYN 3.5m Deep Photometry of M35 (NGC 2168)

    Get PDF
    We present deep BVI observations of the core of M35 and a nearby comparison field obtained at the WIYN 3.5m telescope under excellent seeing. These observations display the lower main sequence in BV and VI CMDs down to V = 23.3 and 24.6, respectively. At these faint magnitudes background field stars are far more numerous than the cluster stars, yet by using a smoothing technique and CMD density distribution subtraction we recover the cluster fiducial main sequence and luminosity function to V = 24.6. We find the location of the main sequence in these CMDs to be consistent with earlier work on other open clusters, specifically NGC 188, NGC 2420, and NGC 2477. We compare these open cluster fiducial sequences to stellar models by Baraffe et al. (1998), Siess et al. (2000), Girardi et al. (2000), and Yi et al. (2001) and find that the models are too blue in both B-V and V-I for stars below ~0.4 Mo. M35 contains stars to the limit of the extracted main sequence, at M ~ 0.10-0.15 Mo, suggesting that M35 may harbor a large number of brown dwarfs, which should be easy targets for near-IR instrumentation on 8-10m telescopes. We also identify a new candidate white dwarf in M35 at V = 21.36 +- 0.01. Depending on which WD models are used to interpret this cluster candidate, it is either a very high mass WD (1.05 +- 0.05 Mo) somewhat older (0.19-0.26 Gyr, 3-4 sigma) than our best isochrone age (150 Myr), or it is a modestly massive WD (0.67-0.78 Mo) much too old (0.42-0.83 Gyr) to belong to the cluster.Comment: 28 pages + 24 figures; to be published in the Sept, 2002 A

    CCD Photometry of the Classic Second Parameter Globular Clusters M3 and M13

    Get PDF
    We present high-precision V, B-V color-magnitude diagrams (CMDs) for the classic second parameter globular clusters M3 and M13 from wide-field deep CCD photometry. The data for the two clusters were obtained during the same photometric nights with the same instrument, allowing us to determine accurate relative ages. Based on a differential comparison of the CMDs using the Delta (B-V) method, an age difference of 1.7 +/- 0.7 Gyr is obtained between these two clusters. We compare this result with our updated horizontal-branch (HB) population models, which confirm that the observed age difference can produce the difference in HB morphology between the clusters. This provides further evidence that age is the dominant second parameter that influences HB morphology.Comment: 27 pages, 12 figures, Accepted for publication in A

    Case study of the evaluation of the life cycle of a façade using the flip teaching method

    Full text link
    [EN] In the constant search for new and innovative pedagogical strategies, a model of teaching is proposed in which the learning of the student and the acquisition of all possible skills is the main thing. This article shows the study carried out by students of the subject "Methods and Advanced Technologies in work", taught in the Master's Degree in Planning and Management in Civil Engineering (MAPGIC) of the Universitat Politècnica de València. By means of the flip teaching or flipped classroom technique, students carry out the evaluation of the life cycle of a type of facade enclosure. This method gives students the responsibility to review the theoretical content so that they can solve their doubts and work on the concepts in class, individually or collaboratively way, as well as knowing, understanding and applying constructive procedures to advanced construction works. In Addition, it will acquire transversal competencies, such as decision-making and problem-solving capacities in terms of designs and projects to be carried out, taking into account ethical, environmental and professional responsibility.The authors are grateful for the support received by the Ministry of Economy, and Business and FEDER funds (Research Project BIA2017-85098-R) and the Universitat Politècnica de València (EXCELCON Educational Innovation and Quality Team).Ata-Ali, N.; Martínez-Muñoz, D.; Yepes, V.; Martí Albiñana, JV. (2019). Case study of the evaluation of the life cycle of a façade using the flip teaching method. IATED. 893-898. https://doi.org/10.21125/iceri.2019.0282S89389

    The Age Dependent Luminosities of the Red Giant Branch Bump, Asymptotic Giant Branch Bump, and Horizontal Branch Red Clump

    Get PDF
    Color-magnitude diagrams of globular clusters often exhibit a prominent horizontal branch (HB) and may also show features such as the red giant branch (RGB) bump and the asymptotic giant branch (AGB) bump. Stellar evolution theory predicts that the luminosities of these features will depend on the metallicity and age of the cluster. We calculate theoretical lines of 2 to 12 Gyr constant age RGB-bumps and AGB-bumps in the V(HB-Bump)--[Fe/H] diagram, which shows the brightness difference between the bump and the HB as a function of metallicity. In order to test the predictions, we identify giant branch bumps in new Hubble Space Telescope color-magnitude diagrams for 8 SMC clusters. First, we conclude that the SMC cluster bumps are RGB-bumps. The data for clusters younger than ~6 Gyr are in fair agreement the relative age dependent luminosities of the HB and RGB-bump. The V(HB-Bump)--[Fe/H] data for clusters older then ~6 Gyr demonstrate a less satisfactory agreement with our calculations. We conclude that ~6 Gyr is a lower bound to the age of clusters for which the Galactic globular cluster, age independent V(HB-Bump)--[Fe/H] calibration is valid. Application of the V(HB-bump)--[Fe/H] diagram to stellar population studies is discussed.Comment: Accepted for publication in the Astrophysical Journal, 30 pages, Latex aaspp4.sty, including 7 postscript figure

    Distances to Populous Clusters in the LMC via the K-Band Luminosity of the Red Clump

    Full text link
    We present results from a study of the distances and distribution of a sample of intermediate-age clusters in the Large Magellanic Cloud. Using deep near-infrared photometry obtained with ISPI on the CTIO 4m, we have measured the apparent K-band magnitude of the core helium burning red clump stars in 17 LMC clusters. We combine cluster ages and metallicities with the work of Grocholski & Sarajedini to predict each cluster's absolute K-band red clump magnitude, and thereby calculate absolute cluster distances. An analysis of these data shows that the cluster distribution is in good agreement with the thick, inclined disk geometry of the LMC, as defined by its field stars. We also find that the old globular clusters follow the same distribution, suggesting that the LMC's disk formed at about the same time as the globular clusters, ~ 13 Gyr ago. Finally, we have used our cluster distances in conjunction with the disk geometry to calculate the distance to the LMC center, for which we find (m-M)o = 18.40 +/- 0.04_{ran} +/- 0.08_{sys}, or Do = 47.9 +/- 0.9 +/- 1.8 kpc.Comment: 31 pages including 5 figures and 7 tables. Accepted for publication in the August 2007 issue of A

    Deep Photometry of the Globular Cluster M5: Distance Estimates from White Dwarf and Main Sequence Stars

    Full text link
    We present deep VI photometry of stars in the globular cluster M5 (NGC 5904) based on images taken with the Hubble Space Telescope. The resulting color-magnitude diagram reaches below V ~ 27 mag, revealing the upper 2-3 magnitudes of the white dwarf cooling sequence, and main sequence stars eight magnitudes and more below the turn-off. We fit the main sequence to subdwarfs of known parallax to obtain a true distance modulus of (m-M)_0 = 14.45 +/- 0.11 mag. A second distance estimate based on fitting the cluster white dwarf sequence to field white dwarfs with known parallax yielded (m-M)_0 = 14.67 +/- 0.18 mag. We couple our distance estimates with extensive photometry of the cluster's RR Lyrae variables to provide a calibration of the RR Lyrae absolute magnitude yielding M_V(RR) = 0.42 +/- 0.10 mag at [Fe/H] = -1.11 dex. We provide another luminosity calibration in the form of reddening-free Wasenheit functions. Comparison of our calibrations with predictions based on recent models combining stellar evolution and pulsation theories shows encouraging agreement. (Abridged)Comment: AASTeX, 29 pages including 5 figures. Complete photometry data and FITS-format images are available at http://physics.bgsu.edu/~layden/ASTRO/PUBL/published.html . Accepted for publication in the Astrophysical Journal, 2005 October 20. Replaced errant wording in last sentence of paragraph 4 of conclusion

    Fast approximation of centrality and distances in hyperbolic graphs

    Full text link
    We show that the eccentricities (and thus the centrality indices) of all vertices of a δ\delta-hyperbolic graph G=(V,E)G=(V,E) can be computed in linear time with an additive one-sided error of at most cδc\delta, i.e., after a linear time preprocessing, for every vertex vv of GG one can compute in O(1)O(1) time an estimate e^(v)\hat{e}(v) of its eccentricity eccG(v)ecc_G(v) such that eccG(v)e^(v)eccG(v)+cδecc_G(v)\leq \hat{e}(v)\leq ecc_G(v)+ c\delta for a small constant cc. We prove that every δ\delta-hyperbolic graph GG has a shortest path tree, constructible in linear time, such that for every vertex vv of GG, eccG(v)eccT(v)eccG(v)+cδecc_G(v)\leq ecc_T(v)\leq ecc_G(v)+ c\delta. These results are based on an interesting monotonicity property of the eccentricity function of hyperbolic graphs: the closer a vertex is to the center of GG, the smaller its eccentricity is. We also show that the distance matrix of GG with an additive one-sided error of at most cδc'\delta can be computed in O(V2log2V)O(|V|^2\log^2|V|) time, where c<cc'< c is a small constant. Recent empirical studies show that many real-world graphs (including Internet application networks, web networks, collaboration networks, social networks, biological networks, and others) have small hyperbolicity. So, we analyze the performance of our algorithms for approximating centrality and distance matrix on a number of real-world networks. Our experimental results show that the obtained estimates are even better than the theoretical bounds.Comment: arXiv admin note: text overlap with arXiv:1506.01799 by other author
    corecore