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The growing demand of flexible electronic devices is increasing the requirements of their power sources. The effect of bending in thin-film batteries is still not well understood. Here, we successfully developed a high active area flexible all-solid-state battery as a model system that consists of thin-film layers of Li 4 Ti 5 O 12 , LiPON, and Lithium deposited on a novel flexible ceramic substrate. A systematic study on the bending state and performance of the battery is presented. The battery withstands bending radii of at least 14 mm achieving 70% of the theoretical capacity. Here, we reveal that convex bending has a positive effect on battery capacity showing an average increase of 5.5%, whereas concave bending decreases the capacity by 4% in contrast with recent studies. We show that the change in capacity upon bending may well be associated to the Li-ion diffusion kinetic change through the electrode when different external forces are applied. Finally, an encapsulation scheme is presented allowing sufficient bending of the device and operation for at least 500 cycles in air. The results are meant to improve the understanding of the phenomena present in thin-film batteries while undergoing bending rather than showing improvements in battery performance and lifetime.

The continuous demand for improved performance in energy storage is driving the evolution of Li-ion battery technology toward emerging battery architectures such as 3D all-solid-state microbatteries (ASB). Being based on solid-state ionic processes in thin films, these new energy storage devices require adequate materials analysis techniques to study ionic and electronic phenomena. This is key to facilitate their commercial introduction. For example, in the case of cathode materials, structural, electrical and chemical information must be probed at the nanoscale and in the same area, to identify the ionic processes occurring inside each individual layer and understand the impact on the entire battery cell. In this work, we pursue this objective by using two well established nanoscale analysis techniques namely conductive atomic force microscopy (C-AFM) and secondary ion mass spectrometry (SIMS). We present a platform to study Li-ion composites with nanometer resolution that allows one to sense a multitude of key characteristics including structural, electrical and chemical information. First, we demonstrate the capability of a biased AFM tip to perform field-induced ionic migration in thin (cathode) films and its diagnosis through the observation of the local resistance change. The latter is ascribed to the internal rearrangement of Li-ions under the effect of a strong and localized electric field. Second, the combination of C-AFM and SIMS is used to correlate electrical conductivity and local chemistry in different cathodes for application in ASB. Finally, a promising starting point towards quantitative electrochemical information starting from C-AFM is indicated.

The growing demand of flexible electronic devices is increasing the requirements of their power sources. The effect of bending in thin-film batteries is still not well understood. Here, we successfully developed a high active area flexible all-solid-state battery as a model system that consists of thin-film layers of Li Ti O , LiPON, and Lithium deposited on a novel flexible ceramic substrate. A systematic study on the bending state and performance of the battery is presented. The battery withstands bending radii of at least 14 mm achieving 70% of the theoretical capacity. Here, we reveal that convex bending has a positive effect on battery capacity showing an average increase of 5.5%, whereas concave bending decreases the capacity by 4% in contrast with recent studies. We show that the change in capacity upon bending may well be associated to the Li-ion diffusion kinetic change through the electrode when different external forces are applied. Finally, an encapsulation scheme is presented allowing sufficient bending of the device and operation for at least 500 cycles in air. The results are meant to improve the understanding of the phenomena present in thin-film batteries while undergoing bending rather than showing improvements in battery performance and lifetime.

A set of distributed robust finite-time state observers was developed and tested to estimate the main biochemical substances in interconnected metabolic networks with complex structure. The finite-time estimator was designed by composing several supertwisting based step-by-step state observers. This segmented structure was proposed accordingly to the partition of metabolic network obtained as a result of applying the observability analysis of the model used to represent metabolic networks. The observer was developed under the assumption that a sufficient and small number of intracellular compounds can be obtained by some feasible analytic techniques. These techniques are enlisted to demonstrate the feasibility of designing the proposed observer. A set of numerical simulations was proposed to test the observer design over the hydrogen producing metabolic behavior of Escherichia coli. The numerical evaluations showed the superior performance of the observer (on recovering immeasurable state values) over classical approaches (high gain). The variations of internal metabolites inserted in the hydrogen productive metabolic networks were collected from databases. This information supplied to the observer served to validate its ability to recover the time evolution of nonmeasurable metabolites.

This article proposes a robust parametric identifier of systems that describe metabolic networks in microorganisms. This identifier implements a robust decentralized parallel differentiator that recovers the time variation of the concentrations of all the substances involved in the metabolic network. The sense of decentralized concept used in this study regards the application of the differentiator in each node of the network without considering the effect of the surrounding nodes. This solution can be obtained under the consideration of robustness provided by the kind of differentiator used in this study. The differentiator is based on the super-twisting algorithm (STA) which is applied to the variation of each substance that is included in the metabolic network. These derivatives are fed into a parallel nonlinear least mean square scheme that succeeds in recovering the parameters that characterize the metabolic network. This identifier is applied to a simplified metabolic network, taken from Escherichia coli that regulates hydrogen production from glucose and it is conformed by 18 reactions. The metabolic network is simulated with parameters obtained from previous studies. Then, these parameters were estimated using the parametric identifier evaluated in this study based on the STA. All the parameters were estimated with less than 5 % error.

Modelamos la decisión de IPO de un empresario en una economía de intercambio y estudiamos los beneficios de diversificación. El empresario inicialmente posee un activo no listado en la bolsa, modelado como árbol de Lucas, y en el momento del IPO el mercado converge a una economía de dos árboles, desarrollada en Cochrane, Longstaff, & Santa- Clara (2007). Resolvemos el problema de tiempo óptimo, y estudiamos los efectos de diversificación sobre el valor de la firma y el consumo del empresario. Tanto el empresario como el mercado se benefician por el IPO y el nuevo escenario diversificado, pero ya que la decisión es tomada por un solo agente, el tiempo óptimo de IPO no maximiza el bienestar de la economía agregada. Esto puede solucionarse con la implementación de subsidios e impuestos. El modelo predice que los IPO debieran estar correlacionados con el tamaño de las firmas dentro de una industria, y explica por qué se espera que las primeras firmas en abrirse al mercado tengan menores betas.

I found your new \"Where's Wally\" style puzzle very entertaining (Eyewitness: inside the new Wembley, September 21),...

Black carbon (BC) from fossil fuel and biomass combustion darkens the snow and makes it melt sooner. The BC footprint of research activities and tourism in Antarctica has likely increased as human presence in the continent has surged in recent decades. Here, we report on measurements of the BC concentration in snow samples from 28 sites across a transect of about 2,000 km from the northern tip of Antarctica (62°S) to the southern Ellsworth Mountains (79°S). Our surveys show that BC content in snow surrounding research facilities and popular shore tourist-landing sites is considerably above background levels measured elsewhere in the continent. The resulting radiative forcing is accelerating snow melting and shrinking the snowpack on BC-impacted areas on the Antarctic Peninsula and associated archipelagos by up to 23 mm water equivalent (w.e.) every summer. The snow surrounding research facilities and shore tourist-landing sites in Antarctica was found to be darker than elsewhere in the continent, which suggests that local emissions of black carbon are accelerating seasonal snowmelt in impacted regions.

En ultimas fechas, diversos medios de comunicacion han emitido notas en el sentido de que la compania de telefonia movil Iusacell pasa por una grave crisis economica al grado tal que se encuentra en quiebra tecnica, y que asi incluso lo han tenido que reconocer y revelar en sus informes sus auditores externos en observancia a las disposiciones legales que en materia contable y del mercado de valores, les resultan aplicables tanto a la propia firma de auditores externos, como a dicha empresa de telefonia celular cuyas acciones son objeto de oferta publica y cotizacion en la Bolsa Mexicana de Valores.Cabe aclarar que el objetivo perseguido con las normas legales que imponen la obligacion de hacer tal revelacion al publico inversionista es procurar que los presentes o potenciales inversionistas cuenten con elementos apropiados para decidir informadamente sobre la conveniencia o no de invertir en tales o cuales valores de los que se ofertan en el mercado bursatil.Tambien es oportuno precisar que, si bien es cierto que la Ley General de Sociedades Mercantiles establece en su articulo 229 como causal de disolucion de una sociedad el que esta haya perdido las dos terceras partes de su capital social, situacion a la que se le ha identificado como quiebra tecnica, tambien es cierto que, conforme a las disposiciones de la Ley de Concursos Mercantiles, una empresa para ser declarada en estado de quiebra, requiere primeramente ser declarada en concurso...