508 research outputs found

    Electrochemically assisted adsorption/desorption of bentazone on activated carbon cloth

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    This paper investigates the use of electrochemical techniques for the removal of a common herbicide, bentazone, from water streams using a carbon-based electrode. Activated carbon cloth with high surface area and narrow micropores was used as electrode. For a better understanding of the process, adsorption was investigated under both open circuit and controlled polarization conditions, the latter in anodic and cathodic directions. It was found that anodic polarization enhances the kinetics of adsorption of the herbicide on the carbon cloth, the extent of which is strongly related to the applied current value. At converse, cathodic polarization induces the reversible desorption of the compound. Moreover, in-situ UV spectra recording on the solution did not show any structural change of the herbicide upon polarization, demonstrating the reversibility of the process for the regeneration of the adsorbent and the recovery of the compound. Based on these experiments, a mechanism is proposed to interpret the reversible sorption of bentazone under polarization.The authors thank Actitex, France, for kindly supplying the activated carbon cloth. COA thanks the CSIC I3P Program, co-financed by the European Social Fund, for a postdoctoral contract. Dr. Khomenko is also acknowledged for fruitful discussionsPeer reviewe

    Solvent-free ionic liquids as in situ probes for assessing the effect of ion size on the performance of electrical double layer capacitors

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    The authors thank Norit for kindly supplying the activated carbon adsorbent. COA thanks MEC, Spain, for the financial support (EX2004-0612). Poznań University of Technology is also acknowledged (Project DS 32/007/2005). The help of Dr. Parra with the Modelling Software and of Dr. Khomenko in the conductivity measurements is acknowledged.Peer reviewe

    Mapping the Mechanical Properties of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) Banded Spherulites by Nanoindentation

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    Nanoindentation provides clear evidence that spherulite banding can be associated with a continuous modulation of mechanical properties from the more compliant peaks to the stiffer valleys. The structural arrangement in polymer-banded spherulites has intrigued scientists for many decades, and the debate has been recently intensified with the advent of new experimental evidence. The present paper approaches this issue by exploring the local mechanical properties of poly(3-hydroxybutyrate-co-3-hydroxyvalerate)-ringed spherulites via nanoindentation and discussing the confidence of the results. It was found that storage modulus and hardness across the banding morphology can be described as a sequence of regular oscillations with a periodicity that exactly matches the one observed using optical and atomic force microscopy. Results are consistent with the model of regular twisting of the lamellae, with flat-on arrangement in the low regions and edge-on lamellae in the crests.The authors wish to thank the MINECO (Ministerio de Economía y Competitividad), Spain, for funding the research reported under grants MAT2013-47898-C2-1-R (covering the costs to publish in open access) and MAT2012-36341. Patricia Enrique-Jimenez acknowledges MINECO for a FPI (Formación Personal Investigador) studentship. We acknowledge support by the CSIC Open Access Publication Initiative through its Unit of Information Resources for Research (URICI)

    Carbon Materials as Additives to WO3 for an Enhanced Conversion of Simulated Solar Light

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    We have explored the impact of the incorporation of nanoporous carbons as additives to tungsten oxide on the photocatalytic degradation of two recalcitrant pollutants: rhodamine B and phenol, under simulated solar light. For this purpose, WO3/carbon mixtures were prepared using three carbon materials with different properties (in terms of porosity, structural order and surface chemistry). Despite the low carbon content used (2 wt. %), a significant increase in the photocatalytic performance of the semiconductor was observed for all the catalysts. Moreover, the influence of the carbon additive on the performance of the photocatalysts was found to be very different for the two pollutants. Carbon additives of hydrophobic nature increased the photodegradation yield of phenol compared to bare WO3, likely due to the higher affinity and stronger interactions of phenol molecules towards basic nanoporous carbons. Oppositely, the use of acidic carbon additives led to higher rhodamine B conversions due to increased acidity of the WO3/carbon mixtures and the stronger affinity of the pollutant for acidic catalyst’s surfaces. As a result, the photooxidation of rhodamine B is favored by means of a coupled (photosensitized and photocatalytic) degradation mechanism. All these results highlight the importance of favoring the interactions of the pollutant with the catalyst’s surface through a detailed design of the features of the photocatalyst

    Thermal and mechanical properties of recycled poly(Lactic acid)

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    Biodegradable polymers have experienced increased attention in recent years because of their wide range of applications in biomedical, packaging and agriculture fields. PLA, poly(lactic acid), is a linear aliphatic biodegradable thermoplastic polyester, with good mechanical properties, thermal stability, processability and low environmental impact, widely used as an alternative to conventional polymers. PLA products can be recycled after use either by remelting and reprocessing the material, or by hydrolysis to basic lactic acid [1]. The object of this communication is the study of the possible variation in physical properties induced by sub sequent reprocessing cycles of PLA

    Comparison of engagement and emotional responses of older and younger adults interacting with 3D cultural heritage artefacts on personal devices

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    The availability of advanced software and less expensive hardware allows museums to preserve and share artefacts digitally. As a result, museums are frequently making their collections accessible online as interactive, 3D models. This could lead to the unique situation of viewing the digital artefact before the physical artefact. Experiencing artefacts digitally outside of the museum on personal devices may affect the user's ability to emotionally connect to the artefacts. This study examines how two target populations of young adults (18–21 years) and the elderly (65 years and older) responded to seeing cultural heritage artefacts in three different modalities: augmented reality on a tablet, 3D models on a laptop, and then physical artefacts. Specifically, the time spent, enjoyment, and emotional responses were analysed. Results revealed that regardless of age, the digital modalities were enjoyable and encouraged emotional responses. Seeing the physical artefacts after the digital ones did not lessen their enjoyment or emotions felt. These findings aim to provide an insight into the effectiveness of 3D artefacts viewed on personal devices and artefacts shown outside of the museum for encouraging emotional responses from older and younger people

    Sub-250 fs, 650 kW Peak Power Harmonic Mode-Locked Fiber Laser with InN-based SESAM

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    43rd. European Conference on Optical Communication (ECOC 2017), Gothemburg, 17-21 Sept.We demonstrate ultrafast harmonically mode-locked fiber lasing in up to 6-km-long rings at 1.56μm with InN SESAM. Fundamental mode-locking with pulse width of 239fs, pulse energy of 155nJ and peak power of 650kW is achieved with a 1-km-long cavity.European CommissionMinisterio de Economía y CompetitividadComunidad de Madri

    Nanoespumas de carbono: Producción por láser, propiedades químico-físicas y potenciales aplicaciones electroquímicas y en catálisis

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    Trabajo presentado a la "XII Reunion del Grupo Español del Carbón" celebrada en Madrid del 20 al 23 de octubre de 2013.Este trabajo ha sido financiado por la Comisión Europea (proyecto LIFE11/ENV/ES 560 “CERAMGLASS”) y el Gobierno de Aragón (Proyecto PI119/09).Peer Reviewe

    The interplay between genotype, metabolic state and cofactor treatment governs phenylalanine hydroxylase function and drug response

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    The discovery of a pharmacological treatment for phenylketonuria (PKU) raised new questions about function and dysfunction of phenylalanine hydroxylase (PAH), the enzyme deficient in this disease. To investigate the interdependence of the genotype, the metabolic state (phenylalanine substrate) and treatment (BH4 cofactor) in the context of enzyme function in vitro and in vivo, we (i) used a fluorescence-based method for fast enzyme kinetic analyses at an expanded range of phenylalanine and BH4 concentrations, (ii) depicted PAH function as activity landscapes, (iii) retraced the analyses in eukaryotic cells, and (iv) translated this into the human system by analyzing the outcome of oral BH4 loading tests. PAH activity landscapes uncovered the optimal working range of recombinant wild-type PAH and provided new insights into PAH kinetics. They demonstrated how mutations might alter enzyme function in the space of varying substrate and cofactor concentrations. Experiments in eukaryotic cells revealed that the availability of the active PAH enzyme depends on the phenylalanine-to-BH4 ratio. Finally, evaluation of data from BH4 loading tests indicated that the patient's genotype influences the impact of the metabolic state on drug response. The results allowed for visualization and a better understanding of PAH function in the physiological and pathological state as well as in the therapeutic context of cofactor treatment. Moreover, our data underscore the need for more personalized procedures to safely identify and treat patients with BH4-responsive PAH deficienc
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