Energy shortage failure prediction in photovoltaic standalone installations by using machine learning techniques

The use of energy storage systems in standalone photovoltaic installations is essential to supply energy demands, independently of solar generation. Accurate prediction of the battery state is critical for the safe, durable, and reliable operation of systems in this type of installations. In this study, an installation located in the area of Aragon (Spain) has been considered. Two methods, based on different types of Recurrent Neural Networks (RNN), are proposed to predict the battery voltage of the installation two days ahead. Specifically, the Nonlinear Auto Regressive with Exogenous Input (NARX) network and the Long Short-Term Memory (LSTM) network are studied and compared. The implemented algorithms process battery voltage, temperature and current waveforms; and rely on the selection of different future scenarios based on weather forecasting to estimate the future voltage of the battery. The proposed methodology is capable of predicting the voltage with a Root Mean Squared Error (RMSE) error of 1.2 V for batteries of 48 V, in critical situations where the installation is running out of energy. The study contributes to the ongoing research of developing preventive control systems that help reduce costs and improve the performance of remote energy storage systems based on renewable energies with a positive outcome

A classification of entanglement in three-qubit systems

We present a classification of three-qubit states based in their three-qubit and reduced two-qubit entanglements. For pure states these criteria can be easily implemented, and the different types can be related with sets of equivalence classes under Local Unitary operations. For mixed states characterization of full tripartite entanglement is not yet solved in general; some partial results will be presented here.Comment: Shortened version. Accepted in EPJ

Force Spectroscopy Imaging and Constriction Assays Reveal the Effects of Graphene Oxide on the Mechanical Properties of Alginate Microcapsules

Microencapsulation of cells in hydrogel-based porous matrices is an approach that has demonstrated great success in regenerative cell therapy. These microcapsules work by concealing the exogenous cells and materials in a robust biomaterial that prevents their recognition by the immune system. A vast number of formulations and additives are continuously being tested to optimize cell viability and mechanical properties of the hydrogel. Determining the effects of new microcapsule additives is a lengthy process that usually requires extensive in vitro and in vivo testing. In this paper, we developed a workflow using nanoindentation (i.e., indentation with a nanoprobe in an atomic force microscope) and a custom-built microfluidic constriction device to characterize the effect of graphene oxide (GO) on three microcapsule formulations. With our workflow, we determined that GO modifies the microcapsule stiffness and surface properties in a formulation-dependent manner. Our results also suggest, for the first time, that GO alters the conformation of the microcapsule hydrogel and its interaction with subsequent coatings. Overall, our workflow can infer the effects of new additives on microcapsule surfaces. Thus, our workflow can contribute to diminishing the time required for the validation of new microcapsule formulations and accelerate their clinical translation

Setups microfluídicos dedicados al cultivo celular

El desarrollo de nuevas herramientas de cultivo celular basadas en microtecnologías permitecontrolar el escenario mecánico, químico y eléctrico de las muestras biológicas, así comomonitorizar sus reacciones de una manera que hasta ahora era imposible. Como consecuencia,es posible generar nuevas vías para la realización de tests “in-vitro” en condiciones muysimilares a las “in-vivo”. Se espera que dicho avance permita reducir la experimentación conanimales y optimizar el desarrollo de nuevos fármacos a través de pruebas de test masivo (highthroughput).Hasta la fecha, los dispositivos microfluídicos para cultivo celular han estado basados entecnología de litografía blanda (soft-lithography), utilizando materiales como el PDMS. Latecnología basada en el material polimérico SU-8 ha sido ya previamente desarrollada y testeadapara aplicaciones del diagnóstico clínico, permitiendo no solo la construcción robusta demicrocanales, sino la posibilidad de integrar sensores y de crear redes de canales en tresdimensiones entre otras características interesantes.Tras la fabricación de los primeros dispositivos microfluídicos en SU-8 y la realización de lainserción de células en su interior, se ha podido corroborar la viabilidad del crecimiento celularen dichos dispositivos, aplicando un flujo de nutrientes continuo y controlado. Este control deflujo y el ambiente biomimético buscado se consiguen mediante el establecimiento de todo unsetup microfluídico consistente en encapsulado para el chip, reservorio, válvulas y microbomba.En este tipo de experimentación es muy importante tener un control preciso del flujo que se leestá aplicando a las células, por lo que el control de la microbomba es uno de los aspectosfundamentales en el desarrollo de setup microfluídicos para cultivo celular

Proposed experimental tests of the Bell-Kochen-Specker theorem

For a two-particle two-state system, sets of compatible propositions exist for which quantum mechanics and noncontextual hidden-variable theories make conflicting predictions for every individual system whatever its quantum state. This permits a simple all-or-nothing state-independent experimental verification of the Bell-Kochen-Specker theorem.Comment: LaTeX, 8 page

Thermoplastic elastomer with advanced hydrophilization and bonding performances for rapid (30 s) and easy molding of microfluidic devices

One of the most important area of research in microfluidic technologies focuses on the identification and characterisation of novel materials with enhanced properties and versatility. Here we present a fast, easy and inexpensive microstructuration method for the fabrication of novel, flexible, transparent and biocompatible microfluidic devices. Using a simple hot-press, we demonstrate the rapid (30s) production of various microfluidic prototypes embossed in a commercially-available soft thermoplastic elastomer (sTPE). This styrenic block copolymer (BCP) material is as flexible as PDMS and as thermoformable as classical thermoplastics. It exhibits high fidelity in replication using SU–8 and epoxy master molds in a highly convenient low-isobar (0.4 bar) and iso-thermal process. Microfluidic devices can then be easily sealed using either a simple hot plate or even room-temperature assembly, allowing them so sustain liquid pressure of 2 and 0.6 bars respectively. The excellent sorption and biocompatibility properties of the microchips were validated via a standard rhodamine dye assay as well as a sensitive yeast cell-based assay. The morphology and composition of the surface area after plasma treatment for hydrophilization purposes are stable and show constant and homogenous distribution of the block nanodomains (∼ 22° after 4 days). These domains, which are evenly distributed at the nanoscale, therefore account for a uniform and convenient surface at a “microfluidic scale device”. To our knowledge, this is the first thermoplastic elastomer material that can be used for fast and reliable fabrication and assembly of microdevices while maintaining a high and stable hydrophilicity

Distribution and mobility of geogenic arsenic in the shallow aquifers of the northeast of La Pampa, Argentina

Groundwater contamination with elevated arsenic (As) and other toxic trace elements has been studied in the central part of the vast Chaco-Pampean Plain, in the city of Quemu Quemu, northeastern La Pampa, Argentina. The groundwater samples were mostly alkaline with pH ranging up to 9.18, oxidizing and characterized by high EC. The concentration of total As (5.58-535 µg/L) and fluoride (0.5-14.2 mg/L) in some samples exceeded the recommended WHO drinking water guideline and the Argentine national drinking water standard. Arsenic was positively correlated with HCO3-, F-, B and V. Long-term consumption of the groundwater could pose a severe health threat for the local community