45 research outputs found

    New lithium ion batteries exploiting conversion/alloying anode and LiFe₀.₂₅Mn₀.₅Co₀.₂₅PO₄ olivine cathode

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    New Li-ion cells are formed by combining a LiFe₀.₂₅Mn₀.₅Co₀.₂₅PO₄ olivine cathode either with Sn-Fe₂O₃-C composite anodes. These active materials exhibit electrochemical properties very attractive in view of practical use, including the higher working voltage of the LiFe₀.₂₅Mn₀.₅Co₀.₂₅PO₄ cathode with respect to conventional LiFePO₄, as well as the remarkable capacity and rate capability of Sn-Fe₂O₃-C and Sn-C anodes. The stable electrode/electrolyte interfaces, demonstrated by electrochemical impedance spectroscopy, along with proper mass balancing and anode pre-lithiation, allow stable galvanostatic cycling of the full cells. The two batteries, namely Sn-Fe₂O₃-C/LiFe₀.₂₅Mn₀.₅Co₀.₂₅PO₄ and Sn-C/LiFe₀.₂₅Mn₀.₅Co₀.₂₅PO₄, reversibly operate revealing promising electrochemical features in terms of delivered capacity, working voltage and stability, thus suggesting these electrodes combinations as suitable alternatives for an efficient energy storage

    A New CuO-Fe₂O₃ ‐Mesocarbon Microbeads Conversion Anode in a High‐Performance Lithium‐Ion Battery with a Li₁.₃₅Ni₀.₄₈Fe₀.₁Mn₁.₇₂O₄ Spinel Cathode

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    A ternary CuO-Fe₂O₃ ‐mesocarbon microbeads (MCMB) conversion anode was characterized and combined with a high‐voltage Li₁.₃₅Ni₀.₄₈Fe₀.₁Mn₁.₇₂O₄ spinel cathode in a lithium‐ion battery of relevant performance in terms of cycling stability and rate capability. The CuO-Fe₂O₃-MCMB composite was prepared by using high‐energy milling, a low‐cost pathway that leads to a crystalline structure and homogeneous submicrometrical morphology as revealed by XRD and electron microscopy. The anode reversibly exchanges lithium ions through the conversion reactions of CuO and Fe₂O₃ and by insertion into the MCMB carbon. Electrochemical tests, including impedance spectroscopy, revealed a conductive electrode/electrolyte interface that enabled the anode to achieve a reversible capacity value higher than 500 mAh g⁻Âč when cycled at a current of 120 mA g⁻Âč. The remarkable stability of the CuO-Fe₂O₃-MCMB electrode and the suitable characteristics in terms of delivered capacity and voltage‐profile retention allowed its use in an efficient full lithium‐ion cell with a high‐voltage Li₁.₃₅Ni₀.₄₈Fe₀.₁Mn₁.₇₂O₄ cathode. The cell had a working voltage of 3.6 V and delivered a capacity of 110 mAh g_{cathode}⁻Âč with a Coulombic efficiency above 99 % after 100 cycles at 148 mA g_{cathode}⁻Âč. This relevant performances, rarely achieved by lithium‐ion systems that use the conversion reaction, are the result of an excellent cell balance in terms of negative‐to‐positive ratio, favored by the anode composition and electrochemical features

    A novel humid electronic nose combined with an electronic tongue for assessing deterioration of wine

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    We report herein the use of a combined system for the analysis of the spoilage of wine when in contact with air. The system consists of a potentiometric electronic tongue and a humid electronic nose. The potentiometric electronic tongue was built with thick-film serigraphic techniques using commercially available resistances and conductors for hybrid electronic circuits; i.e. Ag, Au, Cu, Ru, AgCl, and C. The humid electronic nose was designed in order to detect vapours that emanate from the wine and are apprehended by a moist environment. The humid nose was constructed using a piece of thin cloth sewn, damped with distilled water, forming five hollows of the right size to introduce the electrodes. In this particular case four electrodes were used for the humid electronic nose: a glass electrode, aluminium (Al), graphite and platinum (Pt) wires and an Ag-AgCl reference electrode. The humid electronic nose together with the potentiometric electronic tongue were used for the evaluation of the evolution in the course of time of wine samples. Additionally to the analysis performed by the tongue and nose, the spoilage of the wines was followed via a simple determination of the titratable (total) acidity. © 2011 Elsevier B.V.We thank the Spanish Government (project MAT2009-14564-C04) and the Generalitat Valenciana (project PROME-TEO/2009/016) for support. Luis Gil-Sanchez also thanks the Universidad Politecnica de Valencia for support (Primeros Proyectos de Investigacion - PAID-06-09) and the Generalitat Valenciana (proyectos de I+D para grupos de investigacion emergentes - 2009/8650).Gil Sånchez, L.; Soto Camino, J.; Martínez Mañez, R.; García Breijo, E.; Ibåñez Civera, FJ.; Llobet Valero, E. (2011). A novel humid electronic nose combined with an electronic tongue for assessing deterioration of wine. Sensors and Actuators A: Physical. 171(2):152-158. https://doi.org/10.1016/j.sna.2011.08.006S152158171

    Signatures of Environmental Genetic Adaptation Pinpoint Pathogens as the Main Selective Pressure through Human Evolution

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    Previous genome-wide scans of positive natural selection in humans have identified a number of non-neutrally evolving genes that play important roles in skin pigmentation, metabolism, or immune function. Recent studies have also shown that a genome-wide pattern of local adaptation can be detected by identifying correlations between patterns of allele frequencies and environmental variables. Despite these observations, the degree to which natural selection is primarily driven by adaptation to local environments, and the role of pathogens or other ecological factors as selective agents, is still under debate. To address this issue, we correlated the spatial allele frequency distribution of a large sample of SNPs from 55 distinct human populations to a set of environmental factors that describe local geographical features such as climate, diet regimes, and pathogen loads. In concordance with previous studies, we detected a significant enrichment of genic SNPs, and particularly non-synonymous SNPs associated with local adaptation. Furthermore, we show that the diversity of the local pathogenic environment is the predominant driver of local adaptation, and that climate, at least as measured here, only plays a relatively minor role. While background demography by far makes the strongest contribution in explaining the genetic variance among populations, we detected about 100 genes which show an unexpectedly strong correlation between allele frequencies and pathogenic environment, after correcting for demography. Conversely, for diet regimes and climatic conditions, no genes show a similar correlation between the environmental factor and allele frequencies. This result is validated using low-coverage sequencing data for multiple populations. Among the loci targeted by pathogen-driven selection, we found an enrichment of genes associated to autoimmune diseases, such as celiac disease, type 1 diabetes, and multiples sclerosis, which lends credence to the hypothesis that some susceptibility alleles for autoimmune diseases may be maintained in human population due to past selective processes

    Micromechanical Properties of Injection-Molded Starch–Wood Particle Composites

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    The micromechanical properties of injection molded starch–wood particle composites were investigated as a function of particle content and humidity conditions. The composite materials were characterized by scanning electron microscopy and X-ray diffraction methods. The microhardness of the composites was shown to increase notably with the concentration of the wood particles. In addition,creep behavior under the indenter and temperature dependence were evaluated in terms of the independent contribution of the starch matrix and the wood microparticles to the hardness value. The influence of drying time on the density and weight uptake of the injection-molded composites was highlighted. The results revealed the role of the mechanism of water evaporation, showing that the dependence of water uptake and temperature was greater for the starch–wood composites than for the pure starch sample. Experiments performed during the drying process at 70°C indicated that the wood in the starch composites did not prevent water loss from the samples.Peer reviewe

    New lithium ion batteries exploiting conversion/alloying anode and LiFe0.25Mn0.5Co0.25PO4 olivine cathode

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    New Li-ion cells are formed by combining a LiFe0.25Mn0.5Co0.25PO4 olivine cathode either with Sn-Fe2O3-C or with Sn-C composite anodes. These active materials exhibit electrochemical properties very attractive in view of practical use, including the higher working voltage of the LiFe0.25Mn0.5Co0.25PO4 cathode with respect to conventional LiFePO4, as well as the remarkable capacity and rate capability of Sn-Fe2O3-C and Sn-C anodes. The stable electrode/electrolyte interfaces, demonstrated by electrochemical impedance spectroscopy, along with proper mass balancing and anode pre-lithiation, allow stable galvanostatic cycling of the full cells. The two batteries, namely Sn-Fe2O3-C/LiFe0.25Mn0.5Co0.25PO4 and Sn-C/LiFe0.25Mn0.5Co0.25PO4, reversibly operate revealing promising electrochemical features in terms of delivered capacity, working voltage and stability, thus suggesting these electrodes combinations as suitable alternatives for an efficient energy storage

    Lithium-ion batteries for sustainable energy storage: Recent advances towards new cell configurations

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    The recent advances in the lithium-ion battery concept towards the development of sustainable energy storage systems are herein presented. The study reports on new lithium-ion cells developed over the last few years with the aim of improving the performance and sustainability of electrochemical energy storage. Alternative chemistries involving anode, cathode and electrolyte components are herein recalled in order to provide an overview of state-of-the-art lithium-ion battery systems, with particular focus on the cell configurations currently proposed at the laboratory scale. Hence, the review highlights the main issues related to full cell assembly, which have been tentatively addressed by a limited number of reports, while many papers describe materials investigation in half-cells, i.e., employing lithium metal anodes. The new battery prototypes here described are evaluated in terms of their electrochemical performances, cell balance, efficiency and cycle life. Finally, the applicability of these suitable energy storage systems is evaluated in the light of their most promising characteristics, thus outlining a conceivable scenario for new generation, sustainable lithium-ion batteries

    Metalloporphyrin-based electronic tongue: An application for the analysis of Italian white wines

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    An Electronic Tongue system (ET) composed of "all-solid-state" potentiometric sensors was developed and applied for the identification of white wines. The sensing properties were due to the PVC based membranes doped with several metallo-porphyrins deposited on the surface of glassy carbon working electrodes; potentiometric response towards several ions in a concentration range from 10(-5) M to 10(-1) M were studied and crosssensitivity of sensors was estimated. The sensor array was applied both for the classification and quantitative analysis of "Verdicchio D.O.C." Italian dry white wines produced by nine cantinas. Peculiar parameters of white wines (namely alcoholic degree, volatile acidity, SO2, L-Malic Acid, L-Lactic Acid and Total Polyphenols) individuated by standard analytical methods were compared with the values evaluated by metalloporphyrin-based ET. The system satisfactory discriminates between an artificial wine control and analyzed wines coming from different cantinas and produced in different years. A satisfactory correlation between results of wine analysis performed by certified methods and ET response has been obtained for SO2, L-Malic Acid, and Total Phenols content. The developed procedure allows the monitoring of the acetic acid amount in wines and hence to control wine volatile acidity, so indicating the initial steps of wine spoilage process

    A new nonlinear control of an active rectifier for variable speed generating units

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    This paper deals with a newly conceived (state-feedback) nonlinear control strategy for an active rectifier that is supplied by a Permanent Magnet Synchronous Generator (PMSG). The aim of the proposed control strategy is properly regulate the DC-link voltage within a wide range of system operating conditions by: (i) taking into account a sufficiently rich model, in which the classical simplification – imposing to the DC voltage dynamics a relative degree equal to two – is avoided (so that the input power is not assumed to supply instantaneously the sum of load power and charging rate of the capacitor energy, with the resistance loss and the switching device loss being neglected); (ii) resorting to neither input–output linearizing strategies (involving the DC-link voltage regulation error) that lead to unstable regulation dynamics nor to simplifying design assumptions that overlook derivatives of intermediate reference signals; (iii) avoiding the computational-effort-requirements of Model Predictive Control (MPC) techniques. Simulation and Hardware in the loop (HIL) results illustrate the effectiveness of the proposed control – exhibiting a rather simple structure while guaranteeing local exponential stability for the resulting error system – in terms of Total Harmonic Distortion (THD) and controller response to load and DC voltage reference steps: high band-width and good steady-state waveforms are achieved. Robustness issues and control adaptiveness with respect to uncertain model parameters are also finally addressed
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