A variational model for fracture and debonding of thin films under in-plane loadings

We study fracture and debonding of a thin stiff film bonded to a rigid substrate through a thin compliant layer, introducing a two-dimensional variational fracture model in brittle elasticity. Fractures are naturally distinguished between transverse cracks in the film (curves in 2D) and debonded surfaces (2D planar regions). In order to study the mechanical response of such systems under increasing loads, we formulate a dimension-reduced, rate-independent, irreversible evolution law accounting for both transverse fracture and debonding. We propose a numerical implementation based on a regularized formulation of the fracture problem via a gradient damage functional, and provide an illustration of its capabilities exploring complex crack patterns, showing a qualitative comparison with geometrically involved real life examples. Moreover, we justify the underlying dimension-reduced model in the setting of scalar-valued displacement fields by a rigorous asymptotic analysis using Γ-convergence, starting from the three-dimensional variational fracture (free-discontinuity) problem under precise scaling hypotheses on material and geometric parameters. © 2014 Elsevier Ltd

SEOM guidelines on hydroelectrolytic disorders

Hydroelectrolytic disorders are one of the most common metabolic complications in cancer patients. Although often metabolic alterations affecting various ions are part of the manifestations of the oncological disease, even in the form of paraneoplastic syndrome, we must not forget that very often, these disorders could be caused by various drugs, including some of the antineoplastic agents most frequently used, such as platin derivatives or some biologics. These guidelines review major management of diagnosis, evaluation and treatment of the most common alterations of sodium, calcium, magnesium and potassium in cancer patients. Aside from life-sustaining treatments, we have reviewed the role of specific drug treatments aimed at correcting some of these disorders, such as intravenous bisphosphonates for hypercalcemia or V2 receptor antagonists in the management of syndrome of inappropriate antidiuretic hormone secretion-related hyponatremia

Clustering Techniques Performance for the Coordination of Adaptive Overcurrent Protections

Inclusion of distributed generation and topological changes in a network originate several operating scenarios. For this reason, techniques that adjust the configuration of overcurrent relays have been developed in order to provide protection coordination strategies capable of operating in different schemes. However, the adjustments allowed by these devices are limited. Thus, scenario grouping techniques are proposed to reduce the number of required configurations. This paper aims to evaluate the performance of different grouping techniques with input parameters for coordination strategies of electrical overcurrent protections, where it is required to associate the different modes of operation of a distribution network. For the clustering process, unsupervised learning techniques such as K-means, K-medoids and Agglomerative Hierarchical Clustering were employed. Additionally, for the input characteristics, fault currents, nominal currents and other parameters obtained from the electrical system were taken into account. From the results obtained when evaluating different combinations of techniques and inputs, it is important to mention that the characteristics that describe the different modes of operation necessary for the grouping are decisive for the coordination strategies of electrical protections and that it is not possible to establish a significant difference between the clustering techniques evaluated. Lastly, the combination that presents the best performance was K-means: Manhattan and maximum short-circuit phase currents per relay with a sum of operation time of 428.72s and zero restriction violation. © 2022 IEEE

Adaptive Fault Detection Based on Neural Networks and Multiple Sampling Points for Distribution Networks and Microgrids

Smart networks such as active distribution network (ADN) and microgrid (MG) play an important role in power system operation. The design and implementation of appropriate protection systems for MG and ADN must be addressed, which imposes new technical challenges. This paper presents the implementation and validation aspects of an adaptive fault detection strategy based on neural networks (NNs) and multiple sampling points for ADN and MG. The solution is implemented on an edge device. NNs are used to derive a data-driven model that uses only local measurements to detect fault states of the network without the need for communication infrastructure. Multiple sampling points are used to derive a data-driven model, which allows the generalization considering the implementation in physical systems. The adaptive fault detector model is implemented on a Jetson Nano system, which is a single-board computer (SBC) with a small graphic processing unit (GPU) intended to run machine learning loads at the edge. The proposed method is tested in a physical, real-life, low-voltage network located at Universidad del Norte, Colombia. This testing network is based on the IEEE 13-node test feeder scaled down to 220 V. The validation in a simulation environment shows the accuracy and dependability above 99.6%, while the real-time tests show the accuracy and dependability of 95.5% and 100%, respectively. Without hard-to-derive parameters, the easy-to-implement embedded model highlights the potential for real-life applications. © 2013 State Grid Electric Power Research Institute

Generation Of Entanglement In Quantum Parametric Oscillators Using Phase Control.

The control of quantum entanglement in systems in contact with environment plays an important role in information processing, cryptography and quantum computing. However, interactions with the environment, even when very weak, entail decoherence in the system with consequent loss of entanglement. Here we consider a system of two coupled oscillators in contact with a common heat bath and with a time dependent oscillation frequency. The possibility to control the entanglement of the oscillators by means of an external sinusoidal perturbation applied to the oscillation frequency has been theoretically explored. We demonstrate that the oscillators become entangled exactly in the region where the classical counterpart is unstable, otherwise when the classical system is stable, entanglement is not possible. Therefore, we can control the entanglement swapping from stable to unstable regions by adjusting amplitude and phase of our external controller. We also show that the entanglement rate is approximately proportional to the real part of the Floquet coefficient of the classical counterpart of the oscillators. Our results have the intriguing peculiarity of manipulating quantum information operating on a classical system.51315

Control of entanglement dynamics in a system of three coupled quantum oscillators

Sem informaçãoDynamical control of entanglement and its connection with the classical concept of instability is an intriguing matter which deserves accurate investigation for its important role in information processing, cryptography and quantum computing. Here we consider a tripartite quantum system made of three coupled quantum parametric oscillators in equilibrium with a common heat bath. The introduced parametrization consists of a pulse train with adjustable amplitude and duty cycle representing a more general case for the perturbation. From the experimental observation of the instability in the classical system we are able to predict the parameter values for which the entangled states exist. A different amount of entanglement and different onset times emerge when comparing two and three quantum oscillators. The system and the parametrization considered here open new perspectives for manipulating quantum features at high temperatures.718Sem informaçãoSem informaçãoSem informaçã

Charged Annular Disks and Reissner-Nordstr\"{o}m Type Black Holes from Extremal Dust

We present the first analytical superposition of a charged black hole with an annular disk of extremal dust. In order to obtain the solutions, we first solve the Einstein-Maxwell field equations for sources that represent disk-like configurations of matter in confomastatic spacetimes by assuming a functional dependence among the metric function, the electric potential and an auxiliary function,which is taken as a solution of the Laplace equation. We then employ the Lord Kelvin Inversion Method applied to models of finite extension in order to obtain annular disks. The structures obtained extend to infinity, but their total masses are finite and all the energy conditions are satisfied. Finally, we observe that the extremal Reissner-Nordstr\"{o}m black hole can be embedded into the center of the disks by adding a boundary term in the inversion.Comment: 17 revtex pages, 8 eps figure

ANÁLISIS CINEMÁTICO DE MECANISMOS PLANOS POR EL MÉTODO DE LOS GRAFOS

En este artículo se presenta una simplificación metodológica para el análisis cinemático de mecanismos formados a partir de grupos de Assur de segunda clase, por el método de los grafos. Se presenta un planteamiento general del método y la solución de un mecanismo especific

ANÁLISIS CINEMÁTICO DE MECANISMOS PLANOS POR EL MÉTODO DE LOS GRAFOS

En este artículo se presenta una simplificación metodológica para el análisis cinemático de mecanismos formados a partir de grupos de Assur de segunda clase, por el método de los grafos. Se presenta un planteamiento general del método y la solución de un mecanismo especific

Econometric analysis of the industrial growth determinants in Colombia

An econometric study is carried out using a panel data model with fixed effects to identify the industrial development determinants in Colombia during the term 2005–2015. The database used in the study corresponds to World Bank and the Colombian state. The determinants of industrial growth identified at the theoretical level that allow the enhancement of productive capacities to face foreign competition in Colombia are: innovation; networks of innovations and knowledge among companies and organizations; the interest rate; the capital-product ratio, the unit labor cost; and the exchange rate. The amount invested in scientific, technological and innovation activities by industrial group is the only variable that is not significant in the model