6,014 research outputs found

    An Innovative Methodology to Optimize Aerospace Eco-efficiency Assembly Processes

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    Sustainability and eco-efficiency have been researched in multiple scientific papers since the last years. However the literature is not so abundant when applying those concepts to industrial assembly processes. This paper presents an innovate methodology to optimize aerospace assembly processes. Authors propose the introduction of a new element, the eco-efficiency, along with the traditional criteria, cost and time, currently used for optimization. Using a large Aero-Structure as an industrial case of study, the methodology analyzes the eco-efficiency of an assembly process in connection with a Life Cycle Assessment (LCA) to compute the environmental impact. Results are shown in a dashboard along with the relevant Key Process Indicator (KPI) to help the engineers to select the best assembly processEuropean Union (UE). H2020 DILECO 785367European Union H2020-EU.3.4.5.4-IT

    Assessing the overall perceived quality of the undergraduate students

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    Purpose - The paper is twofold aimed: (i) defining and validating a scale to assess the quality of the university experienced by students and (ii) analyzing the role of the aforementioned di- mensions and their impact on students’ satisfaction. Methodology/Approach - A survey of 2,557 undergraduate students that finished their degrees in 2013 at universities located in the region of Catalonia has been analyzed using Structural Equation Modeling (SEM). An exploratory analysis suggests the final dimensions that were confirmed in a confirmatory analysis. The psychometric characteristics of the scale are provided to show reliability and validity of the constructs. An extra model (also using SEM) assesses the impact of these dimensions on overall satisfac- tion. Findings - The quality is a multifactor construct composed by: (i) “syllabus”, which refers to the quality of the learning methods and the coordination efforts through the whole study period; (ii) “skills development”, referring to the skills that students might acquire along their studies and (iii) “services and facilities” of the university. Moreover, the first and third factors act as “enablers” for the second factor one. Nevertheless, only “Syllabus” dimension affects significantly on students’ satisfaction, whereas “services and facilities” do not have a significant role, although they are necessary in order to provide a good service. Research Limitation/implication - Although the sample is large enough to draw robust re- sults, it is limited the Catalonia. The paper provides recommendations for university managers and public administration authorities in order to allocate the available resources. Originality/Value of paper - In an era of global competition, universities are trying to adapt to these new requirements by expanding they academic offer, introducing innovative teaching methods, providing teaching resources to lecturers, and updating the general services of the university among others. All these services will be considered when students evaluate their experience at the university. The paper contributes with an assessment scale for the holistic service provided by the university within the period that the student is in the university. These findings can be applied to help define attractive academic programs and provide useful insights on how the supporting facilities should be designed to allow students take advantage of their learning process at universities.Postprint (published version

    OPTIMALISASI PENEGAKAN HUKUM DALAM RANGKA MEWUJUDKAN KETAHANAN NASIONAL

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    Penegakan hukum harus dijalankan dengan baik dan efektif dalam mewujudkan Ketahanan Nasional Indonesia. Disamping dengan mengadakan suatu hukum(perundang-undangan, kesiapan mental penegak hukum dalam menjalankan tugasnya harus baik. Hal lain yang perlu dilakukan adalah dengan menertibkan fungsi tugas dan wewenang lembaga-lembaga yang menaungi para penegak hukum. Selanjutnya adalah bagaimana aturan tersebut dilaksanakan oleh masyarakat. Komponen-komponen tersebut harus berjalan selaras dan seimbang prinsip ”Rule Of Law

    A continuous low star formation rate in IZw 18 ?

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    Deep long-slit spectroscopic observations of the blue compact galaxy IZw 18 obtained with the CFH 3.6 m Telescope are presented. The very low value of oxygen abundance previously reported is confirmed and a very homogeneous abundance distribution is found (no variation larger than 0.05 dex) over the whole ionized region. We concur with Tenorio-Tagle (1996) and Devost et al. (1997) that the observed abundance level cannot result from the material ejected by the stars formed in the current burst, and propose that the observed metals were formed in a previous star formation episode. Metals ejected in the current burst of star formation remain most probably hidden in a hot phase and are undetectable using optical spectroscopy. We discuss different scenarios of star formation in IZw 18. Combining various observational facts, for instance the faint star formation rate observed in low surface brightness galaxies van Zee et al. (1997), it is proposed that a low and continuous rate of star formation occurring during quiescent phases between bursts could be a significant source of metal enrichment of the interstellar medium.Comment: 10 pages, 4 Postscript figures, to be published in Astronomy and Astrophysics main journa

    Exhumation of the Sierra de Cameros (Iberian Range, Spain): constraints from low-temperature thermochronology

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    We present new fission-track and (U–Th)/He data from apatite and zircon in order to reconstruct the exhumation of the Sierra de Cameros, in the northwestern part of Iberian Range, Spain. Zircon fission-track ages from samples from the depocentre of the basin were reset during the metamorphic peak at approximately 100 Ma. Detrital apatites from the uppermost sediments retain fission-track age information that is older than the sediment deposition age, indicating that these rocks have not exceeded 110 8C. Apatites from deeper in the stratigraphic sequence of the central part of the basin have fission-track ages of around 40 Ma, significantly younger than the stratigraphic age, recording the time of cooling after peak metamorphic conditions. Apatite (U–Th)/He ages in samples from these sediments are 31–40 Ma and record the last period of cooling during Alpine compression. The modelled thermal history derived from the uppermost sediments indicates that the thermal pulse associated with peak metamorphism was rapid, and that the region has cooled continuously to the present. The estimated palaeogeothermal gradient is around 86 8C km21 and supports a tectonic model with a thick sedimentary fill (c. 8 km) and explains the origin of the low-grade metamorphism observed in the oldest sediments

    Small-scale Intensity Mapping: Extended Lyα\alpha, Hα\alpha and Continuum emission as a Probe of Halo Star Formation in High-redshift Galaxies

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    Lyman alpha halos are observed ubiquitously around star-forming galaxies at high redshift, but their origin is still a matter of debate. We demonstrate that the emission from faint unresolved satellite sources, MUV≳−17M_{\rm UV} \gtrsim -17, clustered around the central galaxies may play a major role in generating spatially extended Lyα\alpha, continuum (UV+VIS{\rm UV + VIS}) and Hα\alpha halos. We apply the analytic formalism developed in Mas-Ribas & Dijkstra (2016) to model the halos around Lyman Alpha Emitters (LAEs) at z=3.1z=3.1, for several different satellite clustering prescriptions. In general, our UV and Lyα\alpha surface brightness profiles match the observations well at 20â‰Črâ‰Č4020\lesssim r \lesssim 40 physical kpc from the centers of LAEs. We discuss how our profiles depend on various model assumptions and how these can be tested and constrained with future Hα\alpha observations by the James Webb Space Telescope (JWST). Our analysis shows how spatially extended halos constrain (i) the presence of otherwise undetectable satellite sources, (ii) the integrated, volumetric production rates of Lyα\alpha and LyC photons, and (iii) their population-averaged escape fractions. These quantities are all directly relevant for understanding galaxy formation and evolution and, for high enough redshifts, cosmic reionization.Comment: 13 pages, 6 figures, edited to match accepted ApJ version. Results unaffected. New descriptive flow-chart figure (Fig.6
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