Search results for "Model theory"
showing 10 items of 681 documents
Studies regarding the use of a neuro-fuzzy mathematical model in order to determine the technological parameters of the polyethylene pipes butt weldi…
2017
The paper analyzes the possibility to use a neuro-fuzzy type mathematical model, with the final goal of establishing the welding parameters for new types and dimensions of pipes and fittings. Anticipating the developing dynamic of polyethylene-made elements, especially pipes and fittings, starting from the current situation when already a wide range of pipes and fittings with different wall thicknesses and nominal working pressures is produced and commercialized, and taking into account also new development, it was considered necessary to find out the welding parameters for any new pipe type and dimension. The usage of existing welding equipment for new pipe dimensions is impossible without…
Superconducting tantalum nitride-based normal metal-insulator-superconductor tunnel junctions
2014
We report the development of superconducting tantalum nitride (TaN$_{x} $) normal metal-insulator-superconductor (NIS) tunnel junctions. For the insulating barrier, we used both AlO$_{x}$ and TaO$_{x}$ (Cu-AlO$_{x}$-Al-TaN$_{x} $ and Cu-TaO$_{x}$-TaN$_{x} $), with both devices exhibiting temperature dependent current-voltage characteristics which follow the simple one-particle tunneling model. The superconducting gap follows a BCS type temperature dependence, rendering these devices suitable for sensitive thermometry and bolometry from the superconducting transition temperature $T_{\text{C}}$ of the TaN$_{x} $ film at $\sim 5$ K down to $\sim$ 0.5 K. Numerical simulations were also performe…
INTERPRETATION OF POTENTIAL INTERMITTENCE TITRATION TECHNIQUE EXPERIMENTS FOR VARIOUS Li-INTERCALATION ELECTRODES
2002
In this paper we compare two different approaches for the calculation of the enhancement factor Wi , based on its definition as the ratio of the chemical and the component diffusion coefficients for species in mixed-conduction electrodes, originated from the “dilute solution” or “lattice gas” models for the ion system. The former approach is only applicable for small changes of the ion concentration while the latter allows one to consider a broad range of intercalation levels. The component diffusion coefficient of lithium ions has been determined for a series of lithium intercalation anodes and cathodes. A new “enhancement factor” for the ion transport has been defined and its relations to…
Direct Imaging of Chiral Domain Walls and Néel‐Type Skyrmionium in Ferrimagnetic Alloys
2021
International audience; The evolution of chiral spin structures is studied in ferrimagnet Ta/Ir/Fe/GdFeCo/Pt multilayers as a function of temperature using scanning electron microscopy with polarization analysis (SEMPA). The GdFeCo ferrimagnet exhibits pure right-hand Néel-type domain wall (DW) spin textures over a large temperature range. This indicates the presence of a negative Dzyaloshinskii-Moriya interaction (DMI) that can originate from both the top Fe/Pt and the Co/Pt interfaces. From measurements of the DW width, as well as complementary magnetic characterization, the exchange stiffness as a function of temperature is ascertained. The exchange stiffness is surprisingly mostly const…
Solvation parameters of solutes: an attempt of improvements in characterization and determination
2008
We are presenting here an updated version of our predictive model of solvation parameters of solutes, based on a simplified molecular topology (J. Chem. Inf. Model, 2006, 46, 1723-1734). The learning experimental database of this model is presently larger than in our first version and includes more compounds with more than one functional group of the same type. This experimental database is also surer, in the sense that it only includes compounds in liquid state at room temperature, when the polarizability of a compound in solution is established via its refractive index in gas or crys- talline state. Indeed, we demonstrate in this paper, a bias in this case.
Technical Parameters Modeling of a Gas Probe Foaming Using an Active Experimental Type Research
2018
ON SOLVABILITY OF THE DAMPED FUČÍK TYPE PROBLEM WITH INTEGRAL CONDITION
2014
The solvability results are established for the boundary value problem with a damping term , x(0) = 0, where x + = max{x, 0}, x - = max{-x, 0}, h is a bounded nonlinearity, µ, λ real parameters. The existence results are based of the knowledge of the Fučík type spectrum for the problem with h ≡ 0
Error Estimates of Uzawa Iteration Method for a Class of Bingham Fluids
2015
The paper is concerned with fully guaranteed and computable bounds of errors generated by Uzawa type methods for variational problems in the theory of visco-plastic fluids. The respective estimates have two forms. The first form contains global constants (such as the constant in the Friedrichs inequality for the respective domain), and the second one is based upon decomposition of the domain into a collection of subdomains and uses local constants associated with subdomains.
Functional A Posteriori Error Estimates for Time-Periodic Parabolic Optimal Control Problems
2015
This article is devoted to the a posteriori error analysis of multiharmonic finite element approximations to distributed optimal control problems with time-periodic state equations of parabolic type. We derive a posteriori estimates of the functional type, which are easily computable and provide guaranteed upper bounds for the state and co-state errors as well as for the cost functional. These theoretical results are confirmed by several numerical tests that show high efficiency of the a posteriori error bounds. peerReviewed
Sensitivity analysis for optimal shape design problems
1989
Various methods for performing the sensitivity analysis in solving optimal shape design problems are outlined. The methods are illustrated in detail in the finite setting of a unilateral boundary value problem of the Dirichlet-Signorini type. The methods are compared in several numerical examples.