Energy partition and segregation for an intruder in a vibrated granular system under gravity

The difference of temperatures between an impurity and the surrounding gas in an open vibrated granular system is studied. It is shown that, in spite of the high inhomogeneity of the state, the temperature ratio remains constant in the bulk of the system. The lack of energy equipartition is associated to the change of sign of the pressure diffusion coefficient for the impurity at certain values of the parameters of the system, leading to a segregation criterium. The theoretical predictions are consistent with previous experimental results, and also in agreement with molecular dynamics simulation results reported in this paper.Comment: To appear in Phys. Rev. Let

Symmetry breaking and clustering in a vibrated granular gas with several macroscopically connected compartments

The spontaneous symmetry breaking in a vibro-fluidized low-density granular gas in three connected compartments is investigated. When the total number of particles in the system becomes large enough, particles distribute themselves unequally among the three compartments. Particles tend to concentrate in one of the compartments, the other two having the (relatively small) same average number of particles. A hydrodynamical model that accurately predicts the bifurcation diagram of the system is presented. The theory can be easily extended to the case of an arbitrary number of connected compartments

Hydrodynamic profiles for an impurity in a open vibrated granular gas

The hydrodynamic state of an impurity immersed in a low density granular gas is analyzed. Explicit expressions for the temperature and density fields of the impurity in terms of the hydrodynamic fields of the gas are derived. It is shown that the ratio between the temperatures of the two components, measuring the departure from energy equipartition, only depends on the mechanical properties of the particles, being therefore constant in the bulk of the system. This ratio plays an important role in determining the density profile of the intruder and its position with respect to the gas, since it determines the sign of the pressure diffusion coefficient. The theoretical predictions are compared with molecular dynamics simulation results for the particular case of the steady state of an open vibrated granular system in absence of macroscopic fluxes, and a satisfactory agreement is found

Ac magnetic susceptibility of a molecular magnet submonolayer directly patterned onto a microSQUID sensor

We report the controlled integration, via Dip Pen Nanolithography, of monolayer dots of ferritin-based CoO nanoparticles (12 Bohr magnetons) into the most sensitive areas of a microSQUID sensor. The nearly optimum flux coupling between these nanomagnets and the microSQUID improves the achievable sensitivity by a factor 100, enabling us to measure the linear susceptibility of the molecular array down to very low temperatures (13 mK). This method opens the possibility of applying ac susceptibility experiments to characterize two-dimensional arrays of single molecule magnets within a wide range of temperatures and frequencies.Comment: 4 pages 3 figure

Deep Learning-Based Fault Detection and Isolation in Solar Plants for Highly Dynamic Days

ICCAD'22: 2022- 6th International Conference on Control, Automation and Diagnosis, Lisbon, Portugal, July 13-15, 2022Solar plants are exposed to numerous agents that degrade and damage their components. Due to their large size and constant operation, it is not easy to access them constantly to analyze possible failures on-site. It is, therefore, necessary to use techniques that automatically detect faults. In addition, it is crucial to detect the fault and know its location to deal with it as quickly and effectively as possible. This work applies a fault detection and isolation method to parabolic trough collector plants. A characteristic of solar plants is that they are highly dependent on the sun and the existence of clouds throughout the day, so it is not easy to achieve methods that work well when disturbances are too variable and difficult to predict. This work proposes dynamic artificial neural networks (ANNs) that take into account past information and are not so sensitive to the variations of the plant at each moment. With this, three types of failures are distinguished: failures in the optical efficiency of the mirrors, flow rate, and thermal losses in the pipes. Different ANNs have been proposed and compared with a simple feedforward ANN, obtaining an accuracy of 73.35%.European Research Council 10.13039/50110000078

A deep learning-based strategy for fault detection and isolation in parabolic-trough collectors

Solar plants are exposed to the appearance of faults in some of their components, as they are vulnerable to the action of external agents (wind, rain, dust, birds …) and internal defects. However, it is necessary to ensure a satisfactory operation when these factors affect the plant. Fault detection and diagnosis methods are essential to detecting and locating the faults, maintaining efficiency and safety in the plant. This work proposes a methodology for detecting and isolating faults in parabolic-trough plants. It is based on a three-layer methodology composed of a neural network to obtain a preliminary detection and classification between three types of fault, a second stage analyzing the flow rate dynamics, and a third stage defocusing the first collector to analyze thermal losses. The methodology has been applied by simulation to a model of the ACUREX plant, which was located at the Plataforma Solar de Almería. The confusion matrices have been obtained, with accuracies over 80% when using the three layers in a hierarchical structure. By forcing all the three layers, the accuracies exceed 90%.Unión Europea - Horizonte 2020 No 789 05

Use of room temperature ionic liquids for the selective fractionation of bioactive ketoses from aldoses

This work deals with the effective fractionation of bioactive ketoses, i.e. lactulose and tagatose, from their corresponding aldoses, lactose and galactose, in equimolar binary mixtures driven by room temperature ionic liquids, i.e. 1-ethyl-3-methylimidazolium dicyanamide ([EMIM][DCA]) and 1-butyl-3-methylimidazolium methyl sulfate ([BMIM][MeSO4]), respectively. Under assayed conditions, tagatose was found to be 6-fold more soluble on [BMIM][MeSO4] than galactose; meanwhile lactulose was 3 times more soluble than lactose on [EMIM][DCA]. As an application example in a more complex sample, a lactose isomerization mixture containing in addition lactulose and monosaccharides was enriched in this ketose by using [EMIM][DCA]. Carbohydrates were then successfully recovered from the ionic liquid following an activated charcoal-based treatment. Overall, lactulose content was enriched from a 24% in the initial isomerization reaction mixture to a 62% in the purified sample. These experimental results demonstrated the potential of ionic liquids as green alternative solvents for the selective fractionation of bioactive ketoses from their corresponding aldoses in food and beverage production.Authors thank Ministerio de Ciencia e Innovación (projects AGL2009-11909 and AGL2011-27884), Ministerio de Economía y Competitividad (project CTQ2012-32957) and the European founding from FEDER program for financial support. L. Ruiz-Aceituno is supported by CSIC by a JAE-Pre grant, co-financed by the European Social Fund (ESF). C. Carrero-Carralero thanks Ministerio de Ciencia e Innovación (Spain) for a predoctoral contract.Peer Reviewe

Freeze desalination by the integration of falling film and block freeze concentration techniques

Block and falling film freeze concentration are two technologies that separate water by freezing,with the potential to desalinate seawater. In this study, the integration of two freeze concentration techniques as an alternative to obtain potable water was analysed. Water with 0.5%–8% NaCl was freeze-concentrated by the falling film technique. The ice from each stage was fractionally thawed to recover the solids retained inPostprint (updated version