Analysis and simulations of multifrequency induction hardening

We study a model for induction hardening of steel. The related differential system consists of a time domain vector potential formulation of the Maxwell's equations coupled with an internal energy balance and an ODE for the volume fraction of {\sl austenite}, the high temperature phase in steel. We first solve the initial boundary value problem associated by means of a Schauder fixed point argument coupled with suitable a-priori estimates and regularity results. Moreover, we prove a stability estimate entailing, in particular, uniqueness of solutions for our Cauchy problem. We conclude with some finite element simulations for the coupled system

Canonical quantization of non-local field equations

We consistently quantize a class of relativistic non-local field equations characterized by a non-local kinetic term in the lagrangian. We solve the classical non-local equations of motion for a scalar field and evaluate the on-shell hamiltonian. The quantization is realized by imposing Heisenberg's equation which leads to the commutator algebra obeyed by the Fourier components of the field. We show that the field operator carries, in general, a reducible representation of the Poincare group. We also consider the Gupta-Bleuler quantization of a non-local gauge field and analyze the propagators and the physical states of the theory.Comment: 18 p., LaTe

Gravitational Lensing Bound On The Average Redshift Of Gamma Ray Bursts In Models With Evolving Lenses

Identification of gravitationally lensed Gamma Ray Bursts (GRBs) in the BATSE 4B catalog can be used to constrain the average redshift $$ of the GRBs. In this paper we investigate the effect of evolving lenses on the of GRBs in different cosmological models of universe. The cosmological parameters $\Omega$ and $\Lambda$ have an effect on the of GRBs. The other factor which can change the $$is the evolution of galaxies. We consider three evolutionary model of galaxies. In particular, we find that the upper limit on$$ of GRBs is higher in evolving model of galaxies as compared to non-evolving models of galaxies.Comment: 23 pages,one plain LaTeX file with three postscript figures This is modified version with recent BATSE efficiency parameter and with the latest F paramete

On a non-isothermal model for nematic liquid crystals

A model describing the evolution of a liquid crystal substance in the nematic phase is investigated in terms of three basic state variables: the {\it absolute temperature} \teta, the {\it velocity field} \ub, and the {\it director field} \bd, representing preferred orientation of molecules in a neighborhood of any point of a reference domain. The time evolution of the velocity field is governed by the incompressible Navier-Stokes system, with a non-isotropic stress tensor depending on the gradients of the velocity and of the director field \bd, where the transport (viscosity) coefficients vary with temperature. The dynamics of \bd is described by means of a parabolic equation of Ginzburg-Landau type, with a suitable penalization term to relax the constraint |\bd | = 1. The system is supplemented by a heat equation, where the heat flux is given by a variant of Fourier's law, depending also on the director field \bd. The proposed model is shown compatible with \emph{First and Second laws} of thermodynamics, and the existence of global-in-time weak solutions for the resulting PDE system is established, without any essential restriction on the size of the data

Preparing children to cope with earthquakes: Building emotional competence

Natural disasters, including earthquakes, can have a traumatic impact on children’s psychological wellbeing and development. The efficacy of interventions aimed at enhancing children’s socio-emotional learning has been documented in the literature. At the same time, these techniques are the key for training children for possible future disasters by enhancing their knowledge about behavioural preparedness and emotional competence. However, research on evidence-based training programs on earthquakes combining digital and traditional activities is scarce. We tested the efficacy of a 10-unit training program for primary school children, developed within the XXX (XXX) project. It aimed at increasing knowledge of and metacognition about earthquakes, safety behaviours, emotions, and coping strategies, through digital (using the web-application XXX® developed ad-hoc) and traditional activities (completing paper-and-pencil tasks). The participants were 548 second and fourth-graders from Italian schools. They were divided into an experimental group (participating in the training program) and a control group. Both groups participated in pretests and posttests to evaluate changes in their knowledge of training-related contents. For ethical reasons, we also measured children’s wellbeing. Generalised linear mixed models indicated an improvement in the experimental group’s knowledge and metacognition about earthquakes, safety behaviours, emotions, and coping strategies after the training program, compared to the control group. Children’s general wellbeing did not deteriorate during participation in the project. The results documented the efficacy of the evidence-based training program developed within the XXX project. The program provides a preventive method for enhancing earthquake-related resilience that could be generalised to other kinds of disasters

Can a web application foster emotional competence in children and adolescents? The case of PandHEMOT®

The COVID-19 pandemic has had many traumatic consequences for the physical and psychological functioning of children and adolescents. Internet-based interventions can reach a large audience and be a potentially powerful resource for promoting well-being among young people. We tested the efficacy of the web application PandHEMOT®, developed ad hoc for increasing knowledge about pandemics, emotions, and emotion regulation. We involved a sample of 147 Italian third and seventh graders. The sample was assigned to an experimental (participating in the training) and a waitlist condition (who participated following a waitlist design). All the participants completed pretest and posttest measures. The intervention was structured into three units. The training took place between November and December 2021. Generalized linear mixed models and linear mixed models revealed that knowledge about pandemics, emotions, emotion regulation, and metacognitive awareness increased for the experimental condition. Moreover, adolescents performed better than children. The findings supported the efficacy of an Internet-based training for increasing children and adolescents' resilience, according to the standards of evidence-based research

Synchronization in Scale Free networks: The role of finite size effects

Synchronization problems in complex networks are very often studied by researchers due to its many applications to various fields such as neurobiology, e-commerce and completion of tasks. In particular, Scale Free networks with degree distribution $P(k)\sim k^{-\lambda}$, are widely used in research since they are ubiquitous in nature and other real systems. In this paper we focus on the surface relaxation growth model in Scale Free networks with $2.5< \lambda <3$, and study the scaling behavior of the fluctuations, in the steady state, with the system size $N$. We find a novel behavior of the fluctuations characterized by a crossover between two regimes at a value of $N=N^*$ that depends on $\lambda$: a logarithmic regime, found in previous research, and a constant regime. We propose a function that describes this crossover, which is in very good agreement with the simulations. We also find that, for a system size above $N^{*}$, the fluctuations decrease with $\lambda$, which means that the synchronization of the system improves as $\lambda$ increases. We explain this crossover analyzing the role of the network's heterogeneity produced by the system size $N$ and the exponent of the degree distribution.Comment: 9 pages and 5 figures. Accepted in Europhysics Letter

Development and early implementation of a public communication campaign to help adults to support children and adolescents to cope with coronavirus-related emotions: A community case study

Epidemics and pandemics can traumatically impact the emotional wellbeing of adults, children, and adolescents in diverse ways. This impact can be reduced by applying a range of evidence-based coping strategies. Based on previous research, we created a pamphlet-based communication campaign designed to assist adults to provide support for young people confronted with emotional distress associated with the pandemic caused by the novel coronavirus [severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)] and the related disease [coronavirus disease (COVID-19)] in 2020. We developed a pamphlet describing the common emotions children and adolescents report feeling in the face of disasters and the coping strategies that have proven effective in mitigating them. The target population was adults who interact with children and adolescents in both formal and informal settings. The pamphlet included basic information on this specific emergency, emotions that might be commonly experienced, and coping strategies for dealing with negative emotions. The aim of this paper is to describe the planning, development, and implementation of the campaign. First, we monitored how the media gave visibility to the campaign during the 40 days following the release of the pamphlet: it potentially reached a large audience at a national and international level through at least 216 media channels included the HEMOT\uae (Helmet for EMOTions) website. Second, Google Analytics\u2122 data from the HEMOT\uae website enabled us to examine the characteristics of the visitors to the website and the behavior of those who viewed the pamphlet. More than 6,000 visitors, most from Europe followed by the Americas, visited the website in the first 40 days after the pamphlet publication. The webpage including the pamphlet obtained over 6,200 views, most directly or via other websites. A cluster analysis suggested that the access to the webpage did not mirror the trend concerning the new cases of COVID-19 in Italy (which increased during the central phase of the campaign) or worldwide (which continued to increase across the 40 days). Third, data gathered with a convenience sample of adults who had consulted the pamphlet provided a perspective on the comprehensibility of the messages conveyed by the pamphlet and on the utility for children and adolescents. The process we have demonstrated in this example could be replicated in different communities and settings to respond to the spread of the COVID-19 or to respond to other widespread or more localized disasters

Impact assessment of different battery energy storage technologies in distribution grids with high penetration of renewable energies

The need for increasing further the penetration of Renewable Energy Sources (RESs) is demanding a change in the way distribution grids are managed. In particular, the RESs intermittent and stochastic nature is finding in Battery Energy Storage (BES) systems its most immediate countermeasure. This work presents a reality-based assessment and comparison of the impact of three different BES technologies on distribution grids with high RES penetration, namely Li-ion, Zn-Air and Redox Flow. To this end, a benchmark distribution grid with real prosumers’ generation and load profiles is considered, with the RES penetration purposely scaled up in such a way as to violate the grid operational limits. Then, further to the BES(s) placement on the most affected grid location(s), the impact of the three BES types is assessed considering two Use Cases: 1) Voltage & Congestion Management and 2) Peak Shaving & Energy shifting. Assessment is conducted by evaluating a set of technical Key Performance Indicators (KPIs), together with a simplified economic analysis. © 2022, European Association for the Development of Renewable Energy, Environment and Power Quality (EA4EPQ). All rights reserved