Search results for "Potential"
showing 10 items of 3348 documents
Behaviour of reactive energy meters in polluted power systems
2006
The reactive energy meters used in electric distribution networks are based on a conventional definition of reactive energy (or power) for sinusoidal voltages and currents, containing only the fundamental frequency component. As a consequence, the performances of reactive energy meters in the presence of harmonic distortion are not tested and their accuracy specifications can be very different from the nominal ones, that are evaluated in sinusoidal conditions. In this paper the authors present a comparative study of the performances of different reactive energy meters, both electromechanical and static, in the presence of harmonic distortion; the study is supported by several simulations an…
Inequalities for Information Potentials and Entropies
2020
We consider a probability distribution p0(x),p1(x),&hellip
The lift computation for an oscillating flat plate in incompressible potential flow
1994
The initial aim of this work was the estimation of the lift acting on a flat plate performing small oscillations in a plane uniform stream by means of a simplified model based on one or at the most two lumped vortices, and the assessment of its results by comparison to those that were exact. The model was found to work well up to a reduced frequency of about 1 or 2, above which the results diverged from those that were correct. In order to improve the model, its behaviour at very high frequencies was then investigated, discovering: (i) that if the number of lumped vortices is greater than one the possibility to impose all boundary conditions is subject to certain geometrical constraints; (i…
Years of life that could be saved from prevention of hepatocellular carcinoma
2016
Summary Background Hepatocellular carcinoma (HCC) causes premature death and loss of life expectancy worldwide. Its primary and secondary prevention can result in a significant number of years of life saved. Aim To assess how many years of life are lost after HCC diagnosis. Methods Data from 5346 patients with first HCC diagnosis were used to estimate lifespan and number of years of life lost after tumour onset, using a semi-parametric extrapolation having as reference an age-, sex- and year-of-onset-matched population derived from national life tables. Results Between 1986 and 2014, HCC lead to an average of 11.5 years-of-life lost for each patient. The youngest age-quartile group (18–61 y…
Robin problems with general potential and double resonance
2017
Abstract We consider a semilinear elliptic problem with Robin boundary condition and an indefinite and unbounded potential. The reaction term is a Caratheodory function exhibiting linear growth near ± ∞ . We assume that double resonance occurs with respect to any positive spectral interval. Using variational tools and critical groups, we show that the problem has a nontrivial smooth solution.
Multiple nodal solutions for semilinear robin problems with indefinite linear part and concave terms
2017
We consider a semilinear Robin problem driven by Laplacian plus an indefinite and unbounded potential. The reaction function contains a concave term and a perturbation of arbitrary growth. Using a variant of the symmetric mountain pass theorem, we show the existence of smooth nodal solutions which converge to zero in $C^1(\overline{\Omega})$. If the coefficient of the concave term is sign changing, then again we produce a sequence of smooth solutions converging to zero in $C^1(\overline{\Omega})$, but we cannot claim that they are nodal.
Superlinear Robin Problems with Indefinite Linear Part
2018
We consider a semilinear Robin problem with an indefinite linear part and a superlinear reaction term, which does not satisfy the usual in such cases AR condition. Using variational methods, together with truncation–perturbation techniques and Morse theory (critical groups), we establish the existence of three nontrivial solutions. Our result extends in different ways the multiplicity theorem of Wang.
A novel numerical meshless approach for electric potential estimation in transcranial stimulation
2015
In this paper, a first application of the method of fundamental solutions in estimating the electric potential and the spatial current density distribution in the brain due to transcranial stimulation, is presented. The coupled boundary value p roblems for the electric potential are solved in a meshless way, so avoiding the use of grid based numerical methods. A multi-spherical geometry is considered and numerical results are discussed.
L'utilisation des reliefs naturels dans l'art gravé et sculpté pariétal du paléolithique supérieur français
2005
Pendant toute la durée du Paléolithique supérieur, en Espagne et en France principalement, les artistes ont réalisé des figurations en utilisant les reliefs naturels et la morphologie des parois de grottes ou d'abris-sous-roche. Ce phénomène artistique, qui a toujours préoccupé les préhistoriens, a suscité les interrogations et les interprétations les plus diverses de la fin du XIXe siècle jusqu'à présent : origine de l'art, préoccupations magico-religieuses, organisation spatiale et sanctuarisation de l'espace souterrain, structures pariétales, chamanisme, techno-cultures, etc. Pendant longtemps, ce que les formes rocheuses pouvaient avoir d'évocateur a été considéré comme la raison d'être…
Melt flow instability and vortex structures in Czochralski growth under steady magnetic fields
2002
Abstract The hydrodynamics of melt motion in the CZ-process of silicon single crystal growth in axial and axial–radial magnetic fields is studied using a physical model. The modeling liquid is eutectics InGaSn. Most attention is paid to the problem of flow stability. A multi-channel system gathering data is used to define the pattern and dynamics of velocity disturbances. Instant spatial distributions of the electric potential induced by motion in the melt are obtained. Temporal evolution of the instant distributions in vertical and horizontal planes of the working volume is under investigation.