Search results for " Model"
showing 10 items of 16868 documents
State-space formulation of scalar Preisach hysteresis model for rapid computation in time domain
2015
A state-space formulation of classical scalar Preisach model (CSPM) of hysteresis is proposed. The introduced state dynamics and memory interface allow to use the state equation, which is rapid in calculation, instead of the original Preisach equation. The main benefit of the proposed modeling approach is the reduced computational effort which requires only a single integration over the instantaneous line segment in the Preisach plane. Numerical evaluations of the computation time and model accuracy are provided in comparison to the CSPM which is taken as a reference model.
The Acoustic Wave Behavior Within the PEA Cell for Space Charge Measurement
2018
In order to evaluate the acoustic wave behavior within the Pulsed Electro Acoustic (PEA) cell, a simulation model has been developed in this work. The model, implemented in Matlab environment, is based on the analogy between acoustic and electrical quantities. Therefore, it was possible to model the PEA cell as cascade connected lossy transmission lines. The model has been validated theoretically by making a comparison with a simulation result found in literature. The experimental validation has also been made by using the PEA cell of the LEPRE high voltage lab. In addition, four graphs have been realized. Two of them can be used to establish in easy and fast way to obtain the minimum groun…
A summary of expressions for central performance parameters of high efficiency solar cell concepts
2019
This work reviews expressions for central performance parameters of various types of PV-concepts when operating at the radiative limit. Some new expressions not published elsewhere are also included. The performance parameters include the short circuit current density, the open circuit voltage, the maximum power density and the optimal voltage. The cell concepts include single junction cells, cells optically coupled to up- and down-converters, intermediate band solar cells and a couple of implementations of multijunction devices. The Lambert W function is used to express the maximum power density.
Negative differential resistance and threshold-switching in conical nanopores with KF solutions
2021
Negative differential resistance (NDR) phenomena are under-explored in nanostructures operating in the liquid state. We characterize experimentally the NDR and threshold switching phenomena observed when conical nanopores are immersed in two identical KF solutions at low concentration. Sharp current drops in the nA range are obtained for applied voltages exceeding thresholds close to 1 V and a wide frequency window, which suggests that the threshold switching can be used to amplify small electrical perturbations because a small change in voltage typically results in a large change in current. While we have not given a detailed physical mechanism here, a phenomenological model is also includ…
Determination of elastoplastic properties of TiO2 thin films deposited on dual phase stainless steel using nanoindentation tests
2010
International audience; In recent years, the extraction of mechanical behaviour of thin films by nanoindentation using sharp indenter geometry has been extensively studied. This work investigates the mechanical properties of TiO2 thin film (1 µm thickness) deposited by spin coating on dual phase Duplex stainless steel and glass substrates. Experiments are carried out with different sharp triangular pyramids (a Cube corner and a Berkovich indenter) using a commercial Nano Indenter® XP apparatus. The substrate effect has been counteracted and an inverse method proposed in literature for bulk material has been adapted to assess the elastoplastic parameters of the tested thin film directly from…
Space‐vector state dynamic model of SynRM considering self‐ and cross‐saturation and related parameter identification
2020
This study proposes a state formulation of the space-vector dynamic model of the Synchronous Reluctance Motor (SynRM) considering both saturation and cross-saturation effects. The proposed model adopts the stator currents as state variables and has been theoretically developed in both the rotor and stator reference frames. The proposed magnetic model is based on a flux versus current approach and relies on the knowledge of 11 parameters. Starting from the definition of a suitable co-energy variation function, new flux versus current functions have been initially developed, based on the hyperbolic functions and, consequently, the static and dynamic inductance versus current functions have be…
Parametric Models for Predicting the Performance of Wind Turbines
2020
Abstract Performances of eight parametric power curve models for wind turbines, which can be used for the planning and management of wind energy projects, are compared in this study. Initially, the manufacturer’s power curves of four wind turbines are compared with their field performances. Then, the parametric models are developed for these turbines which are tested with their site performances. Out of the models, WERA showed the best performance in case of all the turbines. Finally, a method for using WERA in extrapolating the performance of turbines with limited test data is demonstrated with the case of a 1 kW turbine.
Nonlinear response theory for Markov processes II: Fifth-order response functions
2017
The nonlinear response of stochastic models obeying a master equation is calculated up to fifth-order in the external field thus extending the third-order results obtained earlier (G. Diezemann, Phys. Rev. E{\bf 85}, 051502 (2012)). For sinusoidal fields the $5\om$-component of the susceptibility is computed for the model of dipole reorientations in an asymmetric double well potential and for a trap model with a Gaussian density of states. For most realizations of the models a hump is found in the higher-order susceptibilities. In particular, for the asymmetric double well potential model there are two characteristic temperature regimes showing the occurence of such a hump as compared to a …
Carbonyl compounds of Tc, Re, and Bh: Electronic structure, bonding, and volatility.
2018
Calculations of molecular properties of M(CO)5 and MH(CO)5, where M = Tc, Re, and Bh, and of the products of their decomposition, M(CO)4 and MH(CO)4, were performed using density functional theory and coupled-cluster methods implemented in the relativistic program suits such as ADF, DIRAC, and ReSpect. The calculated first M—CO bond dissociation energies (FBDEs) of Bh(CO)5 and BhH(CO)5 turned out to be significantly weaker than those of the corresponding Re homologs. The reason for that is the relativistic destabilization and expansion of the 6d AOs, responsible for weaker σ-forth and π-back donations in the Bh compounds. The relativistic FBDEs of M(CO)5 have, therefore, a Λ-shape behavior …
Pressure‐induced widths and shifts for the ν3 band of methane
1994
International audience; Widths and shifts of methane lines perturbed by nitrogen are calculated using a complex-valued implementation of Robert-Bonamy (RB) theory. The static intermolecular potential is described as a sum of electrostatic forces and Lennard-Jones (6-12) atom-atom terms, using literature values for all physical parameters. Vibrational dependence of the isotropic potential is obtained from the polarizability of methane assuming a dispersion interaction. The repulsive part of the Lennard-Jones accounts for the greatest part of widths, while dispersion interactions are largely responsible for shifts. Although the average error between calculated and observed linewidths (up to J…