132 research outputs found

    Macromodelling for analog design and robustness boosting in bio-inspired computing models

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    Setting specifications for the electronic implementation of biological neural-network-like vision systems on-chip is not straightforward, neither it is to simulate the resulting circuit. The structure of these systems leads to a netlist of more than 100.000 nodes for a small array of 100×150 pixels. Moreover, introducing an optical input in the low level simulation is nowadays not feasible with standard electrical simulation environments. Given that, to accomplish the task of integrating those systems in silicon to build compact, low power consuming, and reliable systems, a previous step in the standard analog electronic design flux should be introduced. Here a methodology to make the translation from the biological model to circuit-level specifications for electronic design is proposed. The purpose is to include non ideal effects as mismatching, noise, leakages, supply degradation, feedthrough, and temperature of operation in a high level description of the implementation, in order to accomplish behavioural simulations that require less computational effort and resources. A particular case study is presented, the analog electronic implementation of the locust's Lobula Giant Movement Detector (LGMD), a neural structure that fires a collision alarm based on visual information. The final goal is a collision threat detection vision system on-chip for automotive applications.European Union IST-2001-38097, TIC2003 - 09817-C02-0

    Locust-inspired vision system on chip architecture for collision detection in automotive applications

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    This paper describes a programmable digital computing architecture dedicated to process information in accordance to the organization and operating principles of the four-layer neuron structure encountered at the visual system of Locusts. This architecture takes advantage of the natural collision detection skills of locusts and is capable of processing images and ascertaining collision threats in real-time automotive scenarios. In addition to the Locust features, the architecture embeds a Topological Feature Estimator module to identify and classify objects in collision course.European Commission IST2001 - 38097Ministerio de Ciencia y Tecnología TIC2003 - 09817- C02 - 0

    “Anonymous” Islam in Spagna? Influenza delle comunità islamiche come gruppi di interesse nelle politiche pubbliche

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    Este libro se erige como una obra importante dentro de una rama de la Ciencia Política aún no muy transitada. Si bien podemos decir que existen estudios sobre la influencia de los grupos de interés en el proceso de implantación de las políticas públicas e, incluso, sobre la influencia que ejercen sobre el mismo los grupos de interés católicos, no es menos cierto que el estudio de la influencia de los grupos de interés islámicos en este ámbito resulta una vía novedosa y poco desarrollada hasta el momento. En este sentido, la obra de Peña Ramos abre un camino con el fin de arrojar luz a esta temática

    Bioethanol Production and Alkali Pulp Processes as Sources of Anionic Lignin Surfactants

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    Lignin is an abundant biopolymer with potential value-added applications that depend on biomass source and fractioning method. This work explores the use as emulsifiers of three native lignin-rich product coming from industrial bioethanol production and alkali or Kraft pulping. In addition to their distinctive characteristics, the different molecular organization induced by emulsification pH is expected to interact in various ways at the water-oil interface of the emulsion droplets. Initially, model oil-in-water (O/W) emulsions of a silicone oil will be studied as a function of lignin source, disperse phase concentration and emulsification pH. Once stablished the effect of such variables, emulsion formulations of three potential bitumen rejuvenators (waste vegetable cooking oil, recycled lubricating oil and a 160/220 penetration range soft bitumen). Droplet size distribution, Z-potential and viscous tests conducted on model emulsions have shown that emulsification pH strongly affects stabilization ability of the lignins tested. Regarding bitumen rejuvenators, lignin emulsification capability will be affected by surfactant source, pH and, additionally, by the dispersed phase characteristics. Lower Z-potential values shown by KL at pH 9 and 11 seem to facilitate emulsification of the less polar disperse phases formed by RLUB and bitumen. In any case, lower particle size and higher yield stress values were found for both bioethanol-derived lignins emulsifying RVO and RLUB at pH 13, which are expected to exhibit a longer stabilit

    Bitumen chemical modification by thiourea dioxide

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    This work evaluates a novel bitumen modification through the use of a chemical agent, thiourea dioxide, substance which has been traditionally used as a reducing agent. Thermogravimetric analysis demonstrated the formation of new chemical compounds, most probably originated through reactions between products from thiourea dioxide thermal decomposition and some highly polar bitumen molecules. As a result of these reactions, which continues even after 60 days, bitumen permanent deformation resistance at high temperature is enhanced, as indicated by a significant increase in its viscosity and elastic features. On the other hand, thiourea dioxide addition produces changes in the bitumen colloidal nature, which improve its flexibility at low in-service temperatures, and consequently its resistance to thermal cracking under loading. In fact, dynamic bending tests indicated a remarkable decrease in the value of binder glass transition temperature, which was further corroborated by differential scanning calorimetry. As a conclusion, thiourea dioxide can be seen as a promising modifiying agent, which can extend the in-service temperature range at which bitumen would present a satisfactory performance.This work is part of a research project sponsored by a MEC-FEDER Programme (Research Project MAT2007-61460) and by a Junta de Andalucía Programme (TEP6689). The authors gratefully acknowledge its financial support. A.A.Cuadri also acknowledges the concession of MEC FPU research fellowship (AP2008-01419).This work is part of a research project sponsored by a MEC - FEDER P rogramme (Research Project MAT2 007 - 61460) and by a Junta de Andaluc í a Programme (TEP6689). The authors gratefully acknowledge its financial support. A.A.Cuadri also acknowledges the concession of MEC FPU research fellowship (AP2008 - 01419).This work is part of a research project sponsored by a MEC-FEDER Programme (Research Project MAT2007-61460) and by a Junta de Andalucia Programme (TEP6689). The authors gratefully acknowledge its financial support. A.A. Cuadri also acknowledges the concession of MEC FPU research fellowship (AP2008-01419)

    Bitumen modifiers for reduced temperature asphalts: a comparative analysis between three polymeric and non-polymeric additives

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    This study presents three bitumen modifiers which may find successful application in the fabrication of binders for warm mix asphalt in the paving industry. In that sense, two non-polymeric additives, thiourea and thiourea dioxide, along with a reactive isocyanate-terminated prepolymer have been evaluated. Viscous flow and linear viscoelasticity tests, at 60 ºC, reveal bituminous modified binders which evolve towards highly viscous materials when subjected to ambient curing. However, at 135 ºC, they show lower viscosity than a typical 3 wt.% SBS binder used as reference. These results suggest modified binders with low viscosity which may contribute to reduce the mix asphalt temperature. On the contrary, they are expected to undergo an important increase in viscosity when the asphalt is in service, which would contribute to improve further their performance. Low temperature performance and effects of short-term and long-term aging were not considered in this study.This work is part of a research project sponsored by a MEC-FEDER Programme of references BES-2008-003572 and AP2008-01419, supported by European Social Fund. The authors gratefully acknowledge its financial support

    Molecular gas in super spiral galaxies

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    We thank the referee for the careful revision of the manuscript and constructive comments. UL acknowledges support by the research projects AYA2017-84897-P and PID2020-114414GB-I00 from the Spanish Ministerio de Economía y Competitividad, from the European Regional Development Funds (FEDER) and the Junta de Andalucía (Spain) grants FQM108. This work is based on observations carried out under project numbers 205-19 and 068-20 with the IRAM 30m telescope. IRAM is supported by INSU/CNRS (France), MPG (Germany) and IGN (Spain). This research made use of the “K-corrections calculator” service available at http://kcor.sai.msu.ru/ . This research made use of Astropy, a community- developed core Python ( http://www.python.org ) package for Astronomy (Astropy Collaboration 2013, 2018); ipython (Pérez & Granger 2007); matplotlib (Hunter 2007); SciPy, a collection of open source software for scientific computing in Python (Virtanen et al. 2020); and NumPy, a structure for efficient numerical computation (van der Walt et al. 2011). This publication makes use of data products from the Wide-field Infrared Survey Explorer, which is a joint project of the University of California, Los Angeles, and the Jet Propulsion Laboratory/California Institute of Technology, funded by the National Aeronautics and Space Administration. This work was made possible by the NASA/IPAC Extragalactic Database and the NASA/ IPAC Infrared Science Archive, which are both operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. We acknowledge the usage of the HyperLeda database ( http://leda.univ-lyon1.fr ).At the highest stellar masses (log(M*) ≳ 11.5 M⊙), only a small fraction of galaxies are disk-like and actively star-forming objects. These so-called ‘super spirals’ are ideal objects to better understand how galaxy evolution proceeds and to extend our knowledge about the relation between stars and gas to a higher stellar mass regime. We present new CO(1–0) data for a sample of 46 super spirals and for 18 slightly lower-mass (log(M*) > 11.0 M⊙) galaxies with broad HI lines – HI fast-rotators (HI-FRs). We analyze their molecular gas mass, derived from CO(1–0), in relation to their star formation rate (SFR) and stellar mass, and compare the results to values and scaling relations derived from lower-mass galaxies. We confirm that super spirals follow the same star-forming main sequence (SFMS) as lower-mass galaxies. We find that they possess abundant molecular gas (mean redshift-corrected molecular gas mass fraction (log(fmol, zcorr) = −1.36 ± 0.02), which lies above the extrapolation of the scaling relation with stellar mass derived from lower-mass galaxies, but within the relation between fmol and the distance to the SFMS. The molecular gas depletion time, τdep = Mmol/SFR, is higher than for lower-mass galaxies on the SFMS (τdep = 9.30 ± 0.03, compared to τdep = 9.00 ± 0.02 for the comparison sample) and seems to continue an increasing trend with stellar mass. HI-FR galaxies have an atomic-to-molecular gas mass ratio that is in agreement with that of lower-mass galaxies, indicating that the conversion from the atomic to molecular gas proceeds in a similar way. We conclude that the availability of molecular gas is a crucial factor to enable star formation to continue and that, if gas is present, quenching is not a necessary destiny for high-mass galaxies. The difference in gas depletion time suggests that the properties of the molecular gas at high stellar masses are less favorable for star formation.Spanish Ministerio de Economía y Competitividad AYA2017-84897-P, PID2020-114414GB-I00European Regional Development Funds (FEDER) AYA2017-84897-P, PID2020-114414GB-I00Junta de Andalucía (Spain) FQM108INSU/CNRS (France) 205-19, 068-20MPG (Germany) 205-19, 068-20IGN (Spain) 205-19, 068-20IPACNational Aeronautics and Space Administration NASACentre National de la Recherche Scientifique CNR

    A CNN-driven locally adaptive CMOS image sensor

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    A bioinspired model for mixed-signal array mimics the way in which images are processed in the visual pathway. Focal-plane processing of images permits local adaptation of photoreceptor structures in silicon. Beyond simple resistive grid filtering, nonlinear and anisotropic diffusion can be programmed in this CNN chip. This paper presents the local circuitry for sensors adaptation based on the mixed-signal VLSI parallel processing infrastructure in CMOS

    Rheological and phase behaviour of paraffin wax/bitumen blends with thermal storage characteristics

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    This paper analyses the thermomechanical properties, heat storage characteristics and compatibility of bitumen blends with a paraffin wax, having a melting point around 60 ◦C, as phase change material. To that end, temperature sweeps in the linear viscoelastic range, technological properties, Modulated Differential Scanning Calorimetry (MDSC), and cross-polarised optical microscopy observations were carried out on blends and pure compounds. The obtained results reveal a partial compatibility between the compounds and the development of a multiphasic microstructure, where the paraffin-rich or bitumen-rich domains form the continuous phase depending on the concentration, with the phase inversion around 20 wt% wax. Below this threshold concentration, the disperse paraffin-rich phase acts as filler that reinforces the continuous bitumen matrix until it reaches the melting transition. Above the critical concentration for the phase inversion, the continuous paraffin- rich phase controls the rheological response. However, both phases retain their own identity and show their individual transitions and relaxations. Despite the partial compatibility, a high degree of crystallinity is found, especially for high paraffin contents, which would result in a significant capacity to store thermal energy, for applications such as solar thermal collection or thermoregulation materials for buildings, etc.This work is part of the projects TED2021-131284B-I00 and PID2020-116905RB-I00 funded by MCIN/AEI/10.13039/ 501100011033 (Spanish Ministry of Science and Innovation) and European Union “NextGenerationEU” and the Cátedra Fundación CEPSA edition 2022. Adrián Tenorio also acknowledges financial support from Junta de Andalucía through the post-doctoral Grant POSTDOC_21_00644, co-funded by the EU Fondo Social Europeo (FSE)

    Non-bituminous binders formulated with bio-based and recycled materials for energy-efficient roofing applications

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    Non-bituminous binders have been designed as potential roofing materials with sustainable characteristics. To that end, three bio-based rosin esters (R), a waste cooking oil (O) and a recycled polyethylene from greenhouse agriculture (LDPEr) have been used in their formulations. A comprehensive rheological, microstructural, calorimetric, and technological characterization have been performed on binary (polymer/oil or rosin/oil) and ternary (polymer/rosin/oil) blends, allowing the compatibility among binder compounds to be studied. Additionally, thermal conductivity and solar radiation tests have been conducted on a selected non-bituminous binder and compared with a reference polymer modified bitumen. The formulation composed of 61.0% phenolic-modified rosin, 30.5% oil and 8.5% LDPEr has shown suitable mechanical properties for roofing materials, and has exhibited enhanced energy efficiency derived from its light yellowish to brownish color. Under the experimental radiant flux conditions, surface temperature of the non-bituminous binder was 8 °C lower than that of the black bitumen. Moreover, conduction heat transfer through this roofing material was about 14% lower than that conducted through a bitumen-based membrane with the same thickness. Accordingly, developed binders are expected to behave as reflective building materials aiming to reduce the heat island effects and save energy.This work is part of GreenAsphalt project (ref. 802C1800001), cofunded by FEDER European Programme (80%) and Junta de Andalucía (Consejería de Economía, Conocimiento, Empresas y Unversidades/ Agencia-IDEA), and has been also co-funded by FEDER/Junta de Andalucía-Consejería de Economía y Conocimiento/Project UHU- 1256916. Clara Delgado-S´anchez also acknowledges financial support from Junta de Andalucía through post-doctoral Grant No. DC 01228 (PAIDI 2020), co-funded by the EU Fondo Social Europeo (FSE). Funding for open access charge: Universidad de Huelva / CBUA
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