109 research outputs found
Fundamentals of Enzymatic Electrochemical Systems
No full textBioelectrochemical Systems (BESs) are innovative and sustainable devices that combine biological and electrochemical processes to engineer sensors, treat wastewater and/or produce electricity, fuels or high-value chemicals. In BESs, scientists have managed to incorporate biological catalysts, i.e. enzymes and/or microorganisms, and make them work into advanced electrochemical cells. BESs operate under mild conditions ? at close to ambient temperature and pressure and at circumneutral pH ? and represent a sustainable alternative to precious metal-based systems. Interestingly, enzymes and microorganisms are able to catalyze an extremely large variety of chemical reactions and process a wide variety of organic substrates, including dozens of biofuels and waste products. Incorporating biological catalysts into devices, while keeping their activity and achieving electrical communication with electrode surfaces, is a critical challenge when trying to advance the field of BESs. From implantable enzymatic biosensors to microbial electrosynthesis, and from laboratory-scale systems and fundamental studies to marketed devices, this book will provide a comprehensive overview of recent advances related to functional electrodes for BESs. Suitable for researchers, and graduate students of chemistry, biochemistry, materials science and environmental science and technology.Fil: Flexer, Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia de Jujuy. Universidad Nacional de Jujuy. Centro de Investigaciones y Transferencia de Jujuy; ArgentinaFil: Brun, N.. Université Montpellier II; Franci
Nanocarbon-Based Enzymatic Electrodes
No full textBioelectrochemical Systems (BESs) are innovative and sustainable devices that combine biological and electrochemical processes to engineer sensors, treat wastewater and/or produce electricity, fuels or high-value chemicals. In BESs, scientists have managed to incorporate biological catalysts, i.e. enzymes and/or microorganisms, and make them work into advanced electrochemical cells. BESs operate under mild conditions ? at close to ambient temperature and pressure and at circumneutral pH ? and represent a sustainable alternative to precious metal-based systems. Interestingly, enzymes and microorganisms are able to catalyze an extremely large variety of chemical reactions and process a wide variety of organic substrates, including dozens of biofuels and waste products. Incorporating biological catalysts into devices, while keeping their activity and achieving electrical communication with electrode surfaces, is a critical challenge when trying to advance the field of BESs. From implantable enzymatic biosensors to microbial electrosynthesis, and from laboratory-scale systems and fundamental studies to marketed devices, this book will provide a comprehensive overview of recent advances related to functional electrodes for BESs. Suitable for researchers, and graduate students of chemistry, biochemistry, materials science and environmental science and technology.Fil: Brun, Nicolas. Université Montpellier II; FranciaFil: Baccour, Mohamed. Université Montpellier II; FranciaFil: Flexer, Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia de Jujuy. Universidad Nacional de Jujuy. Centro de Investigaciones y Transferencia de Jujuy; Argentin
Maybe You Could Close Your Eyes While I Dance: ‘Age’, ‘Ageing’ and ‘In/visibility’ as choreographic drivers in Yael Flexer & Galit Liss’s Acting Our Age
No full textThe chapter examines Yael Flexer and Galit Liss’s shared interest in Age, Ageing and ‘In/visibility’ as choreographic drivers for the creation of professional works with cross-generational and over 60s female performers. It hones in on their recent joint touring production Acting Our Age (2023) co-created with an international cast of performers aged 26-76, delineating the different ways in which age, ageing and in/visibility manifest as choreographic form and content bringing to the fore a methodology that prioritises somatic, socio-political and ethical values attuned to the ageing body in performance (Farmer et al 2022, Liss 2024).
The work uses a variety of choreographic strategies that build on Liss and Flexer’s previous independent works. These include an informal and proximal mode of performance to engender embodied viewing, unearthing autobiographical nuggets of material used as text or as impetus for movement creation (Suslik 2019:84), playing with different modes and references to the visible and invisible - what is displayed and what is hidden from view - to underscore the intertwining of presence and representation (Flexer 2020) and a pointing towards co-authorship and nonauthoritarian choreography (Lepecki 2013). As a dancer’s personal movement archive serves a key choreographic component in Acting Our Age (2023), the discussion also touches on notions of ‘the body as archive’ drawing on writing by Lepecki (2010), Foellmer (2020), Adair & Griffiths (2020) and Schwaiger (2012). However, rather than exploring the re-staging of repertoire , the writing (and performed work) focus on the ways in which the archive is used as choreographic device in relation to the overarching theme of age. Similarly, notions of ‘choreopolicing’ and ‘choreopolitics’ as discussed by Lepecki (2013) ground a discussion of the ways in which socially constructed conventions of the ‘danceable’ (Laermans 2015) and the disciplining function of dance underlies and frames audiences and dancers’ own perceptions of age and stage performance (Schwaiger 2012)
El potencial tecnológico alrededor del litio
No full textLa minería del litio resalta la disparidad entre nuestra realidad como exportadores de recursos primarios y nuestra falta de capacidad para agregar valor a dichos recursos. Aunque existen varios proyectos a futuro, para cuya concreción aún no hay fechas, en la actualidad dos mineras en fase de producción y una fábrica de cloruro de litio son los únicos emprendimientos productivos en nuestro país vinculados al litio. La actividad extractiva se concentra en la Puna. En nuestro grupo consideramos que existen tres potenciales ejes de desarrollo tecnológico en torno al litio.Fil: Flexer, Victoria. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro de Investigacion y Desarrollo En Materiales Avanzados y Almacenamiento de Energia de Jujuy. - Universidad Nacional de Jujuy. Centro de Investigacion y Desarrollo En Materiales Avanzados y Almacenamiento de Energia de Jujuy. - Gobierno de la Provincia de Jujuy. Centro de Investigacion y Desarrollo En Materiales Avanzados y Almacenamiento de Energia de Jujuy; Argentin
José María Rico García (1978-2014): "in memoriam"
No full textTabla de contenido:
Introducción por José A. Gómez Pedrero...3
Ciencia y Deporte por Luis M. Sánchez Brea ....6
El lugar de Chema por Javier Alda ....8
Memories of José María in Bordeaux (Recuerdos de José María en Burdeos) por Ashod
Aradian ....11
Discussion avec José (Hablar con José) por Stephanie Delair ...6
Palabras para José por Victoria Flexer ....18
Homenaje a José María por Alessandro Veltri ....20
Publicaciones de José María Rico García ....21Sección Deptal. de Óptica (Óptica)Fac. de Óptica y OptometríaFALSEunpu
Modelling and experiments on self-assembled enzyme systems for electrochemical generation of biosensor signal
No full textSe comparan datos experimentales de respuesta amperométrica para biosensores enzimáticos con modelos que acoplan procesos de difusión-reacción. Se trabajó con Glucosa Oxidasa (GOx, E.C. 1.1.3.4) y mediadores redox artificiales: el complejo [Os(bpy)2ClpyCOOH]+ en el caso homogéneo; y un análogo del mismo unido covalentemente a polialilamina (PAH-Os), que se autoensambla electrostáticamente capa-por-capa junto a GOx dando lugar a un biosensor totalmente integrado. Se ajustaron datos experimentales para el sistema homogéneo a las fórmulas analíticas aproximadas del modelo de Albery (JEC, 323, (1992), 97). A baja concentración de glucosa se observaron voltagramas cíclicos no estacionarios, con desarrollo de un pico de corriente y marcada histéresis, contrariamente a lo predicho por el modelo. Se compararon voltagramas experimentales y simulados numéricamente, en el marco de un modelo más completo que considera el desarrollo de perfiles de concentración. Se reporta además inactivación de la enzima presente en solución de glucosa. Se analizaron cambios en la estructura y la electrocatálisis de películas al variar la densidad de carga lineal de PAH-Os modificando el pH de las soluciones de autoensamblado. La respuesta del sistema inmovilizado se analizó según el modelo de Pratt-Bartlett (JEC, 397, (1995), 61) con el objeto de validar el mismo. Se trabajó con películas de espesor variable y un amplio intervalo de concentraciones de glucosa. Los datos experimentales arrojaron un buen ajuste a las fórmulas aproximadas. También se ajustaron usando una rutina Simplex combinada con la resolución numérica de las ecuaciones diferenciales sin emplear simplificaciones. Los parámetros de ajuste fueron acotados alrededor de los valores hallados con las fórmulas aproximadas. El análisis combinado mediante fórmulas analíticas aproximadas y simulaciones numéricas resultó útil para la extracción de parámetros desconocidos y comprender mejor los factores que afectan la respuesta amperométrica.Experimental data of amperometric response for enzyme biosensors is compared with models that couple diffusion-reaction processes. We have worked with Glucose Oxidase (GOx, E.C. 1.1.3.4) and artificial redox mediators: the complex [Os(bpy)2ClpyCOOH]+ for the homogeneous system, and a similar complex covalently attached to poly(allylamine), PAH-Os, which is electrostatically self-assembled layer-by-layer together with GOx to build up an integrated biosensor. Experimental data for the homogeneous system was fitted to the approximate analytical equations given by Albery’s model (JEC, 323, (1992), 97). At low glucose concentration non-steady state cyclic voltammograms with peak maximum and evident hysteresis were observed, contrary to the model’s predictions. Cyclic voltammograms were simulated according to a more complete model that allows development of concentration profiles (not considered by Albery) and compared to the experimental voltammograms. We also report on enzyme inactivation when present in glucose solutions. We studied changes in the structure and electrocatalysis of enzyme films when changing the polymer linear charge density by adjusting the PAH-Os adsorption solution pH. The amperometric output of the system was studied according to Pratt-Bartlett’s model (JEC, 397, (1995), 61) with the aim to validate such model. We studied films of varying thickness in a wide glucose concentration range. The fitting of the experimental data to the approximate analytical solutions showed good agreement. This data was in turn fitted using a Simplex routine coupled to the numerical simulation of the complete (unsimpliffied) differential equations. The fitting parameters were constrained around the values found with the analytical equations. The combined analysis using approximate analytical solutions and numerical simulations proved useful for the extraction of unknown parameters and for a better understanding of the factors affecting the amperometric output.Fil: Flexer, Victoria. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina
Is it possible to recover lithium compounds from complex brines employing electromembrane processes exclusively?
No full textResearch to develop direct lithium extraction technologies from aqueous sources is fundamental due to the environmental and techno-economic shortcomings of the evaporitic technology currently in use. Electromembrane processes are an attractive alternative since they could be much faster, more readily adaptable to brines of different compositions, sustainable since they use electrons as reactants, avoiding waste production, the use of chemicals, and decreasing the water footprint. Valuable Li+ ions are only a very minor component in a complex matrix of very high ionic strength with co-existing cations, most importantly Mg2+ and Na+, displaying similar chemical properties. A review from the recent literature shows that adaptation from the simple electrodialysis configuration will be needed to selectively recover pure lithium products. Testing of the proposed methodologies at meaningful concentrations, representative of real brines is key to bring these closer to industrial scale applications.Fil: Díaz Nieto, César Horacio. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro de Investigacion y Desarrollo En Materiales Avanzados y Almacenamiento de Energia de Jujuy. - Universidad Nacional de Jujuy. Centro de Investigacion y Desarrollo En Materiales Avanzados y Almacenamiento de Energia de Jujuy. - Gobierno de la Provincia de Jujuy. Centro de Investigacion y Desarrollo En Materiales Avanzados y Almacenamiento de Energia de Jujuy; ArgentinaFil: Flexer, Victoria. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro de Investigacion y Desarrollo En Materiales Avanzados y Almacenamiento de Energia de Jujuy. - Universidad Nacional de Jujuy. Centro de Investigacion y Desarrollo En Materiales Avanzados y Almacenamiento de Energia de Jujuy. - Gobierno de la Provincia de Jujuy. Centro de Investigacion y Desarrollo En Materiales Avanzados y Almacenamiento de Energia de Jujuy; Argentin
Purposely Designed Hierarchical Porous Electrodes for High Rate Microbial Electrosynthesis of Acetate from Carbon Dioxide
No full textCarbon-based products are crucial to our society, but their production from fossil-based carbon is unsustainable. Production pathways based on re-use of CO2 will achieve ultimate sustainability. Furthermore, the costs of renewable electricity production are decreasing at such a high rate, that electricity is expected to be the main energy carrier from 2040 onwards. Electricity-driven novel processes that convert CO2 into chemicals need to be further developed. Microbial electrosynthesis is a biocathode-driven process in which electroactive microorganisms derive electrons from solid-state electrodes to catalyse the reduction of CO2 or organics and generate valuable extracellular multicarbon reduced products. Microorganisms can be tuned to high-rate and selective product formation. Optimization and up-scaling of microbial electrosynthesis to practical, real life applications is dependent upon performance improvement while maintaining low cost. Extensive biofilm development, enhanced electron transfer rate from solid-state electrodes to microorganisms and increased chemical production rate require optimized microbial consortia, efficient reactor designs, and improved cathode materials. This Account is about the development of different electrode materials purposely designed for improved microbial electrosynthesis: NanoWeb-RVC and EPD-3D. Both type of electrodes are biocompatible, highly conductive three-dimensional hierarchical porous structures. Both chemical vapour deposition (CVD) and electrophoretic deposition were used to grow homogeneous and uniform carbon nanotubes layers on the honeycomb structure of reticulated vitreous carbon. The high surface area to volume ratio of these electrodes maximizes the available surface area for biofilm development, i.e. enabling an increased catalyst loading. Simultaneously, the nanostructure makes it possible for a continuous electroactive biofilm to be formed, with increased electron transfer rate and high coulombic efficiencies. Fully autotrophic biofilms from mixed-cultures developed on both type of electrodes relying on CO2 as the sole carbon source and the solid-state-electrode as the unique energy supply.We present first the synthesis and characteristics of the bare electrodes. We then report the outstanding performance indicators of these novel biocathodes: current densities up to -200 A m 2, and acetate production rates up to 1330 g m-2 day-1, with electron and CO2 recoveries into acetate very close to 100 % for mature biofilms. The performance indicators are still amongst the highest reported by either purposely designed or commercially available biocathodes. Finally, we made use of the Titration and off-gas analysis sensor (TOGA) to elucidate the electron transfer mechanism in these efficient biocathodes. Planktonic cells in the catholyte were found irrelevant for acetate production. We identified the electron transfer to be mediated by biologically?induced H2. H2 is not detected in the head-space of the reactors , unless CO2 feeding is interrupted or the cathodes sterilized. Thus the biofilm is extremely efficient in consuming the generated H2. Finally, we successfully demonstrated the use of a synthetic biogas mixture as a CO2 source. We thus proved the potential of microbial electrosynthesis for the simultaneous upgrading of biogas, while fixating CO2 via the production of acetate.Fil: Flexer, Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigación y Desarrollo en Materiales Avanzados y Almacenamiento de Energía de Jujuy - Universidad Nacional de Jujuy. Centro de Investigación y Desarrollo en Materiales Avanzados y Almacenamiento de Energía de Jujuy - Gobierno de la Provincia de Jujuy. Centro de Investigación y Desarrollo en Materiales Avanzados y Almacenamiento de Energía de Jujuy; ArgentinaFil: Jourdin, Ludovic. Delft University of Technology; Países Bajo
Review- Non-Carbonaceous Materials as Cathodes for Lithium-Sulfur Batteries
No full textLithium-sulfur batteries are presented as a promising alternative for the operation of those devices, including electric vehicles,that require higher specific capacity than current lithium-ion technology. Unfortunately, lithium-sulfur batteries suffer from severallimitations that still produce a relatively fast capacity fading and poor utilization of active materials.In order to alleviate the disadvantages that arise at the cathode, several researchers have searched for new electrode materials. Becauseof the long standing tradition in the use of carbons in energy storage systems, carbonaceous cathodes have been the most popularchoice. Recently, however, there has been a trend for the study of non-carbonaceous materials as cathodes in lithium-sulfur systems.Materials such as polymers, metal oxides, metal carbides, amongst many others were reported, showing excellent properties whichmake them compete side by side with state of the art carbonaceous cathodes. Thesematerials have generally improved the conductivityof the conventional sulfur electrode, and have provided a 3D soft adsorbent porous structure, which efficiently traps polysulfides.These characteristics are reflected in an improved electrochemical performance, reaching, in some cases, capacity retention valuesclose to 1000 mA h g−1 after 100 cycles at high discharge rate. Here, we propose a review of these non-carbonaceous cathodes.Fil: Arias, Analía Natalí. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro de Investigacion y Desarrollo En Materiales Avanzados y Almacenamiento de Energia de Jujuy. - Universidad Nacional de Jujuy. Centro de Investigacion y Desarrollo En Materiales Avanzados y Almacenamiento de Energia de Jujuy. - Gobierno de la Provincia de Jujuy. Centro de Investigacion y Desarrollo En Materiales Avanzados y Almacenamiento de Energia de Jujuy; ArgentinaFil: Tesio, Alvaro Yamil. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro de Investigacion y Desarrollo En Materiales Avanzados y Almacenamiento de Energia de Jujuy. - Universidad Nacional de Jujuy. Centro de Investigacion y Desarrollo En Materiales Avanzados y Almacenamiento de Energia de Jujuy. - Gobierno de la Provincia de Jujuy. Centro de Investigacion y Desarrollo En Materiales Avanzados y Almacenamiento de Energia de Jujuy; ArgentinaFil: Flexer, Victoria. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro de Investigacion y Desarrollo En Materiales Avanzados y Almacenamiento de Energia de Jujuy. - Universidad Nacional de Jujuy. Centro de Investigacion y Desarrollo En Materiales Avanzados y Almacenamiento de Energia de Jujuy. - Gobierno de la Provincia de Jujuy. Centro de Investigacion y Desarrollo En Materiales Avanzados y Almacenamiento de Energia de Jujuy; Argentin
Lithium recovery from brines: A vital raw material for green energies with a potential environmental impact in its mining and processing
No full textThe electrification of our world is driving a strong increase in demand for lithium. Energy storage is paramount in electric and hybrid vehicles, in green but intermittent energy sources, and in smart grids in general. Lithium is a vital raw material for the build-up of both currently available lithium-ion batteries, and prospective next generation batteries such as lithium-air and lithium sulphur. The continued availability of lithium can only rely on a strong increase of mining and ore processing. It would be an inconsistency if the increased production of lithium for a more sustainable society would be associated with non-sustainable mining practices. Currently 2/3 of the world production of lithium is extracted from brines, a practice that evaporates on average half a million litres of brine per ton of lithium carbonate. Furthermore, the extraction is chemical intensive, extremely slow, and delivers large volumes of waste. This technology is heavily dependent on the geological structure of the deposits, brine chemical composition and both climate and weather conditions. Therefore, it is difficult to adapt from one successful exploitation to new deposits. A few years of simulations and piloting are needed before large scale production is achieved. Consequently, this technology is struggling with the current surge in demand. At time of writing, only 5 industrial scale facilities are in operation worldwide, highlighting the shortcomings in this technology. Both mining companies and academics are intensively searching for new technologies for lithium recovery from brines. However, focus on the chemistry of brine processing has left unattended the analysis of the sustainability of the overall process. Here we review both the current available technology and new proposed methodologies. We make a special focus on an overall sustainability analysis, with particular emphasis to the geological characteristics of deposits and water usage in relation to mining processes.Fil: Flexer, Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentina. Centro de Investigación y Desarrollo en Materiales Avanzados y Almacenamiento de Energía de Jujuy; ArgentinaFil: Baspineiro, Celso Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentina. Centro de Investigación y Desarrollo en Materiales Avanzados y Almacenamiento de Energía de Jujuy; ArgentinaFil: Galli, Claudia Inés. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; Argentina. Universidad Nacional de Salta. Facultad de Ciencias Naturales; Argentin
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