Determination of the zero-order fringe position in digital speckle pattern interferometry

A method for determining the position of the zero-order fringe in a metrological experiment with digital speckle pattern interferometry is proposed. It is based on an averaging procedure with shifted images obtained before and after a load is applied. This technique is a complement to the phase-shifting methods. Experimental examples are shown

Fixed grid finite element analysis for 3D structural problems

Fixed Grid (FG) methodology was first introduced by García and Steven as an engine for numerical estimation of two-dimensional elasticity problems -- The advantages of using FG are simplicity and speed at a permissible level of accuracy -- Two dimensional FG has been proved effective in approximating the strain and stress field with low requirements of time and computational resources -- Moreover, FG has been used as the analytical kernel for different structural optimisation methods as Evolutionary Structural Optimisation, Genetic Algorithms (GA), and Evolutionary Strategies -- FG consists of dividing the bounding box of the topology of an object into a set of equally sized cubic elements -- Elements are assessed to be inside (I), outside (O) or neither inside nor outside (NIO) of the object -- Different material properties assigned to the inside and outside medium transform the problem into a multi-material elasticity problem -- As a result of the subdivision NIO elements have non-continuous properties -- They can be approximated in different ways which range from simple setting of NIO elements as O to complex noncontinuous domain integration -- If homogeneously averaged material properties are used to approximate the NIO element, the element stiffness matrix can be computed as a factor of a standard stiffness matrix thus reducing the computational cost of creating the global stiffness matrix. An additional advantage of FG is found when accomplishing re-analysis, since there is no need to recompute the whole stiffness matrix when the geometry changes -- This article presents CAD to FG conversion and the stiffness matrix computation based on non-continuous elements -- In addition inclusion/exclusion of O elements in the global stiffness matrix is studied -- Preliminary results shown that non-continuous NIO elements improve the accuracy of the results with considerable savings in time -- Numerical examples are presented to illustrate the possibilities of the metho

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

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

Una evaluación de línea base múltiple de la terapia de aceptación y compromiso centrada en pensamiento negativo repetitivo en trastorno por pánico

Although cognitive-behavioral therapy (CBT) is efficacious for treating panic disorder, a segment of the population is not treated due to the treatment length and the acceptability of interoceptive exposure. This study explored the efficacy of a brief protocol based on acceptance and commitment therapy (ACT) focused on repetitive negative thinking (RNT) in adults suffering from panic disorder. We designed a 4-session RNT-focused ACT protocol because previous CBT studies considered this length "ultra-brief." Additionally, although conducting exposure is consistent with the ACT model, we did not include explicit exposure exercises to increase the intervention acceptability. A randomized, multiple-baseline design across three participants was implemented with a 3-month follow-up. The effect of the intervention was evaluated through weekly scores on the Depression Anxiety and Stress Scale – 21 (DASS-21; S. H. Lovibond & P. F. Lovibond, 1995), Penn State Worry Questionnaire (PSWQ; Meyer et al., 1990), and the frequency of panic attacks. After the intervention, all participants ceased to experience panic attacks and showed clinically significant changes in the DASS-Total and PSWQ. The effect sizes comparable across designs were very large and statistically significant for the DASS-Total (d= 2.48), DASS-Depression (d= 1.45), DASS-Anxiety (d= 1.93), DASS-Stress (d= 1.63), and PSWQ (d= 2.36). All three participants also showed clinically significant changes and large effect sizes in experiential avoidance (d= 3.26), cognitive fusion (d= 3.58), and valued living (Progress: d= 0.72, Obstruction: d= 2.43). In conclusion, brief RNT-focused ACT interventions might be efficacious for treating panic disorder.Aunque la terapia cognitivo-conductual (TCC) es eficaz en el trastorno de pánico, un segmento de la población no recibe tratamiento debido a su duración y aceptabilidad de la exposición interoceptiva. Este estudio exploró la eficacia de la terapia de aceptación y compromiso (ACT) focalizada en pensamiento negativo repetitivo (PNR) en adultos con trastorno por pánico. Se diseñó un protocolo de 4 sesiones porque estudios previos han considerado esta duración como "ultra breve". Pese a que la exposición es consistente con el modelo ACT, no incluimos ejercicios de exposición explícita para aumentar la aceptabilidad de la intervención. Se implementó un diseño de línea de base múltiple aleatorizado a través de tres participantes con un seguimiento de 3 meses. El efecto de la intervención se evaluó con la Depression Anxiety and Stress Scale - 21 (DASS-21, S. H. Lovibond y P. F. Lovibond, 1995), el Penn State Worry Questionnaire (PSWQ; Meyer et al., 1990) y la frecuencia de ataques de pánico. Tras la intervención, los tres participantes dejaron de experimentar ataques de pánico y mostraron cambios clínicamente significativos en DASS-Total y PSWQ. Los tamaños del efecto comparables a través de diseños fueron muy grandes y estadísticamente significativos para DASS-Total (d = 2.48), DASS-Depresión (d = 1.45), DASS-Ansiedad (d = 1.93), DASS-Estrés (d = 1.63) y PSWQ (d = 2.36). Los participantes mostraron cambios clínicamente significativos y grandes tamaños del efecto en evitación experiencial (d = 3.26), fusión cognitiva (d = 3.58) y valores (Progreso: d = 0.72, Obstrucción: d = 2.43)

Techno-economic Feasibility of A Trust and Grid-aware Coordination Scheme

The massive penetration of active customers throughout Home Energy Management Systems (HEMS) may cause adverse effects on the power grid, including rebound peaks, instabilities, and power congestion. The concept of coordination has arisen in literature to mitigate these effects and relieve power grid stress. Their advantages have been discussed for different market types as well as at different grid scales. However, it is imperative to develop proofs-of-concept and test not only the economic feasibility of such programs but also the technical one. This paper presents a cosimulation-based framework that facilitates economic and technical studies for coordination programs. A case study is presented, with eighteen residential users and a local coordinator within a Stackelberg game. At the customer level, flexibility is achieved through electric thermal storage (ETS). The program exploits salient features of blockchain algorithms to increase security at the demand aggregation level. The technical feasibility was evaluated through the Peak-to-average (PAR) ratio, active power losses, and the voltage profile using power flow methods over the IEEE 33-node feeder. This study’s findings demonstrate the coordination programs’ ability to bring economic benefits and reduce the PAR. Furthermore, they suggest that although coordination programs can assist in flattening the power profile, they could create adverse effects on the power grid in critical scenarios

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

Local invertibility in Sobolev spaces with applications to nematic elastomers and magnetoelasticity

We define a class of deformations in W^1,p(\u3a9,R^n), p>n 121, with positive Jacobian that do not exhibit cavitation. We characterize that class in terms of the non-negativity of the topological degree and the equality between the distributional determinant and the pointwise determinant of the gradient. Maps in this class are shown to satisfy a property of weak monotonicity, and, as a consequence, they enjoy an extra degree of regularity. We also prove that these deformations are locally invertible; moreover, the neighbourhood of invertibility is stable along a weak convergent sequence in W^1,p, and the sequence of local inverses converges to the local inverse. We use those features to show weak lower semicontinuity of functionals defined in the deformed configuration and functionals involving composition of maps. We apply those results to prove existence of minimizers in some models for nematic elastomers and magnetoelasticity