This paper introduces new analytical expressions that relate between voltage and current of a nonlinear two-port network. These formulas are defined and derived, analytically, from <inline-formula> ...<tex-math notation="LaTeX">{X} </tex-math></inline-formula>-parameters. They are also extension of the well-known linear two-port network parameters. These formulations are defined as follows. Linearized impedance parameters (<inline-formula> <tex-math notation="LaTeX">{Z} </tex-math></inline-formula>-parameters) relate harmonic voltage components to harmonic current components at both network ports. Linearized admittance parameters are the inverse of linearized <inline-formula> <tex-math notation="LaTeX">{Z} </tex-math></inline-formula>-parameters and relate harmonic current components to harmonic voltage components. Linearized cascade parameters and linearized scattering transfer parameters relate entities at the input to that ones at the output of the network. Linearized hybrid parameters and linearized inverse hybrid parameters are defined in terms of a mixture of port variables. The proposed approach has been evaluated, and very good agreement has been obtained.
In order to solve the parameter dependence problem in model predictive control, an improved model predictive current control (MPCC) method based on the incremental model for surface-mounted ...permanent-magnet synchronous motor drives is proposed in this paper. First, the parameter sensitivity of a conventional MPCC method is analyzed, which indicates that the parameter mismatches would cause prediction current error and inaccurate delay compensation. Therefore, an incremental prediction model is introduced in this paper to eliminate the use of permanent magnetic flux linkage in a prediction model. Among the parameter of the incremental prediction model, only inductance mismatch contributes to the prediction error, since the influence of resistance mismatch on the control performance is very small. Therefore, in order to improve the antiparameter-disturbance capability of the MPCC method, an inductance disturbance controller, which includes the inductance disturbance observer and inductance extraction algorithm, is presented to update accurate inductance information for the whole control system in real time. Finally, simulation and experimental results both show that the proposed method can effectively eliminate the influence of the parameter mismatches on the control performance and reduce the parameter sensitivity of the MPCC method.
The existing fault prognosis techniques of aeroengine mostly focus on a single monitoring parameter under stable condition, and have low adaptability to new prognosis scenes. To boost the fault ...prognosis capability cross aeroengines, modified deep autoencoder (MDAE) driven by multi-source parameters is proposed in this article. First, the sensitive multi-source parameters are selected and fused using linear local tangent space alignment to define a fused health index (FHI) to characterize performance degradation of aeroengine. Second, MDAE model is constructed with adaptive Morlet wavelet to flexibly establish accurate mapping hidden in the FHI under analysis. Third, parameter transfer learning is used to provide good initial parameters for enabling the constructed MDAE to have cross-domain fault prognosis capability. The proposed method is used to analyze both the simulation multisource performance degradation parameters of aeroengines (system level) and experiment run-to-failure bearing datasets (component level). The results confirm the feasibility of the proposed method in cross-domain fault prognosis of aeroengines, which outperforms the existing methods.
We present updated results from the NOvA experiment for νμ→νμ and νμ→νe oscillations from an exposure of 8.85×1020 protons on target, which represents an increase of 46% compared to our previous ...publication. The results utilize significant improvements in both the simulations and analysis of the data. A joint fit to the data for νμ disappearance and νe appearance gives the best-fit point as normal mass hierarchy, Δm322=2.44×10−3 eV2/c4, sin2θ23=0.56, and δCP=1.21π. The 68.3% confidence intervals in the normal mass hierarchy are Δm322∈2.37,2.52×10−3 eV2/c4, sin2θ23∈0.43,0.51∪0.52,0.60, and δCP∈0,0.12π∪0.91π,2π. The inverted mass hierarchy is disfavored at the 95% confidence level for all choices of the other oscillation parameters.
Lab-2-Field Entwicklungsumgebung Katona, László; Pedro Osvaldo Bedolla Velazquez; Vorlaufer, Georg ...
BHM. Berg- und hüttenmännische Monatshefte,
01/2018, Volume:
163, Issue:
5
Journal Article
Peer reviewed
Die Senkung von Entwicklungszeiten und Kosten sind wesentliche Treiber für die produzierende Industrie. Gerade die Entwicklung neuer Werkstoffe zeigt dahingehend ein großes Potential, dass die ...derzeit eingesetzten Standardentwicklungsprozesse extrem zeit- und kostenaufwendig sind.In diesem Beitrag wird eine Lab-2-Field Methode vorgestellt, welche durch Verknüpfung von ausgesuchten Labortests mit einer numerischen Systemsimulation die Möglichkeiten der virtuellen Produkt- und Werkstoffentwicklung aufzeigt. Die Anwendbarkeit dieser Methode wird anhand eines Anwendungsfalles aus der Landwirtschaft (Kreiseleggenzinken) dargestellt mit dem Ziel, neue Verschleißschutzschichten zur Lebensdauererhöhung von Bodenbearbeitungsgeräten zu entwickeln.Basierend auf dem Standard Verschleißtest mittels Reibrad (ASTM G65-04) werden Verschleißparameter für neue Werkstofftypen ermittelt. Mittels Finite Elemente Simulation wird dieser Test virtuell nachgerechnet und daraus Parameter für die Systemsimulation des gesamten Zinkens ermittelt. In dieser Systemsimulation wird die Feldanwendung unter Berücksichtigung der realen Belastungsdaten (Bodenbeschaffenheit, Fahrprofil, Pressungen, und mehr) abgebildet und in einem iterativen Prozess das zeitlich aufgelöste Verschleißbild ermittelt.Die Validierung des Verschleißbildes mit realen Feldtests zeigt eine qualitativ gute Übereinstimmung. Ein Optimierungspotential der dargestellten Lab-2-Field Methode ist in der Wahl der Parameter für das Bodenmodell anzugeben.Mit der präsentierten Methode wurde ein effizientes und kostensparendes Werkzeug zur Entwicklung neuer Verschleißschutzlösungen erarbeitet. Dabei können sowohl neue Werkstoffe als auch das Design von Komponenten hinsichtlich ihres realen Anwendungsgebietes entwickelt und optimiert werden.
A novel method for observer-based control of disturbed polytopic linear parameter varying (LPV) systems with inexactly measured scheduling parameters is investigated in this study. Despite the ...imperfect scheduling parameters knowledge, the proposed control method ensures the closed-loop induced L2-norm performance criterion. Unlike the previous methods, the inexact scheduling parameters are not assumed to be proportional to the original scheduling parameters of the LPV system. Employing both cases of parameter-dependent and parameter-independent Lyapunov functions, sufficient design conditions in terms of linear matrix inequalities are provided using Finsler's lemma. Numerical examples are included to demonstrate the efficiency of the proposed method and its superiority over the previous techniques. Moreover, a practical case study, i.e. clutchless automated manual transmission system is considered and controlled by the developed approach numerically.
•Thermokinetic study for pea residues was carried out.•Kinetic parameters were determined using model-free methods.•Thermodynamic parameters reflected product formation would be favored.•Evolved ...gaseous products were determined by TG/DSC-FTIR system.•Effect of temperature and heating rate on products were investigated.
In this study agricultural waste biomass pea residue was investigated for its potential to be used in pyrolysis for production of bioenergy. Experiments were carried out in a TG/DSC-FTIR under an inert nitrogen medium at different heating rates. Kinetic parameters of pyrolysis were calculated using model free iso-conversional models. The determined activation energy and pre-exponential factor values were ranged between 184.4 and 311.8 kJ mol−1 and 3.36E+16–1.23E+28, respectively. Thermodynamic parameters, such as change in enthalpy, Gibbs free energy and entropy were also calculated. DSC plots of samples showed that for all heating rates the reactions showed an exothermic behavior. Evolved gaseous species were investigated simultaneously during pyrolysis using a FTIR spectrometer coupled to TGA system. The change in profile of gaseous product release depending on temperature and heating rate was also studied. Considering kinetic and thermodynamic analysis besides proximate analysis, pea waste has potential for bioenergy production via pyrolysis.
Gaia Data Release 3 Arenou, F.; Faigler, S.; Kervella, P. ...
Astronomy and astrophysics (Berlin),
06/2023, Volume:
674
Journal Article, Web Resource
Peer reviewed
Open access
Context.
The
Gaia
DR3 catalogue contains, for the first time, about 800 000 solutions with either orbital elements or trend parameters for astrometric, spectroscopic, and eclipsing binaries, and ...combinations of these three.
Aims.
With this paper, we aim to illustrate the huge potential of this large non-single-star catalogue.
Methods.
Using the orbital solutions and models of the binaries, we have built a catalogue of tens of thousands of stellar masses or lower limits thereof, some with consistent flux ratios. Properties concerning the completeness of the binary catalogues are discussed, statistical features of the orbital elements are explained, and a comparison with other catalogues is performed.
Results.
Illustrative applications are proposed for binaries across the Hertzsprung-Russell Diagram (HRD). Binarity is studied in the giant branch and a search for genuine spectroscopic binaries among long-period variables is performed. The discovery of new EL CVn systems illustrates the potential of combining variability and binarity catalogues. Potential compact object companions are presented, mainly white dwarf companions or double degenerates, but one candidate neutron star is also found. Towards the bottom of the main sequence, the orbits of previously suspected binary ultracool dwarfs are determined and new candidate binaries are discovered. The long awaited contribution of
Gaia
to the analysis of the substellar regime shows the brown dwarf desert around solar-type stars using true rather than minimum masses, and provides new important constraints on the occurrence rates of substellar companions to M dwarfs. Several dozen new exoplanets are proposed, including two with validated orbital solutions and one super-Jupiter orbiting a white dwarf, all being candidates requiring confirmation. Besides binarity, higher order multiple systems are also found.
Conclusions.
By increasing the number of known binary orbits by more than one order of magnitude,
Gaia
DR3 will provide a rich reservoir of dynamical masses and an important contribution to the analysis of stellar multiplicity.
Land surface models incorporate a large number of process descriptions, containing a multitude of parameters. These parameters are typically read from tabulated input files. Some of these parameters ...might be fixed numbers in the computer code though, which hinder model agility during calibration. Here we identified 139 hard‐coded parameters in the model code of the Noah land surface model with multiple process options (Noah‐MP). We performed a Sobol' global sensitivity analysis of Noah‐MP for a specific set of process options, which includes 42 out of the 71 standard parameters and 75 out of the 139 hard‐coded parameters. The sensitivities of the hydrologic output fluxes latent heat and total runoff as well as their component fluxes were evaluated at 12 catchments within the United States with very different hydrometeorological regimes. Noah‐MP's hydrologic output fluxes are sensitive to two thirds of its applicable standard parameters (i.e., Sobol' indexes above 1%). The most sensitive parameter is, however, a hard‐coded value in the formulation of soil surface resistance for direct evaporation, which proved to be oversensitive in other land surface models as well. Surface runoff is sensitive to almost all hard‐coded parameters of the snow processes and the meteorological inputs. These parameter sensitivities diminish in total runoff. Assessing these parameters in model calibration would require detailed snow observations or the calculation of hydrologic signatures of the runoff data. Latent heat and total runoff exhibit very similar sensitivities because of their tight coupling via the water balance. A calibration of Noah‐MP against either of these fluxes should therefore give comparable results. Moreover, these fluxes are sensitive to both plant and soil parameters. Calibrating, for example, only soil parameters hence limit the ability to derive realistic model parameters. It is thus recommended to include the most sensitive hard‐coded model parameters that were exposed in this study when calibrating Noah‐MP.
Key Points
Hydrologic fluxes of Noah‐MP are sensitive to standard parameters as well as hard‐coded values
Most sensitive model parameter is hard‐coded in soil surface resistance for evaporation
Latent heat and runoff are sensitive to both plant and soil parameters
Context.
Useful information can be retrieved by analysing the transit light curve of a planet-hosting star or induced radial velocity oscillations. However, inferring the physical parameters of the ...planet, such as mass, size, and semi-major axis, requires preliminary knowledge of some parameters of the host star, especially its mass or radius, which are generally inferred through theoretical evolutionary models.
Aims.
We seek to present and test a whole algorithm devoted to the complete characterisation of an exoplanetary system thanks to the global analysis of photometric or radial velocity time series combined with observational stellar parameters derived either from spectroscopy or photometry.
Methods.
We developed an integrated tool called MCMCI. This tool combines the Markov chain Monte Carlo (MCMC) approach of analysing photometric or radial velocity time series with a proper interpolation within stellar evolutionary isochrones and tracks, known as isochrone placement, to be performed at each chain step, to retrieve stellar theoretical parameters such as age, mass, and radius.
Results.
We tested the MCMCI on the HD 219134 multi-planetary system hosting two transiting rocky super Earths and on WASP-4, which hosts a bloated hot Jupiter. Even considering different input approaches, a final convergence was reached within the code, we found good agreement with the results already stated in the literature and we obtained more precise output parameters, especially concerning planetary masses.
Conclusions.
The MCMCI tool offers the opportunity to perform an integrated analysis of an exoplanetary system without splitting it into the preliminary stellar characterisation through theoretical models. Rather this approach favours a close interaction between light curve analysis and isochrones, so that the parameters recovered at each step of the MCMC enter as inputs for purposes of isochrone placement.
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