Nonlinear Crest, Trough, and Wave Height Distributions in Sea States With Double-Peaked Spectra

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
Felice Arena ◽  
C. Guedes Soares
Keyword(s):  
Monte Carlo ◽  
Atlantic Ocean ◽  
Monte Carlo Simulations ◽  
Wave Height ◽  
Deep Water ◽  
Second Order ◽  
Statistical Distribution ◽  
Random Waves ◽  
Sea Waves ◽  
Two Parameters

The peak to trough distributions of nonlinear high sea waves in bimodal sea states in deep water are investigated. The statistical distribution of wave height is first analyzed by considering the Boccotti’s expression, where the parameters of the distribution are calculated for some bimodal spectra of sea states recorded in the Atlantic Ocean. The nonlinear crest and trough distributions are then obtained, particularizing for two peaked spectra the second-order Fedele and Arena expression, which depends on two parameters. The results have been finally validated by means of Monte Carlo simulations of second-order random waves with bimodal spectra.

Nonlinear Peak to Trough Distributions in Sea States With Double-Peaked Spectra

2007 ◽  
Author(s):  
Felice Arena ◽  
C. Guedes Soares
Keyword(s):  
Monte Carlo ◽  
Atlantic Ocean ◽  
Monte Carlo Simulations ◽  
Wave Height ◽  
Second Order ◽  
Statistical Distribution ◽  
Random Waves ◽  
Sea Waves ◽  
Nonlinear Random Waves ◽  
Two Parameters

The peaks to trough distributions of nonlinear high sea waves in bi-modal sea states are investigated. The statistical distribution of wave height is firstly investigated by considering the Boccotti’s distribution, where the parameters of the distribution are calculated for some bimodal spectra of sea states recorded in the Atlantic Ocean. The nonlinear crest and trough distributions are then obtained particularizing for two peaked spectra the second-order Fedele & Arena distribution, which depends upon two parameters. The results have been finally validated by means of Monte Carlo simulations of nonlinear random waves with bimodal spectra.

scholarly journals Ferromagnetic and spin-glass like transition in the q-neighbor Ising model on random graphs

2021 ◽  
Vol 94 (3) ◽  
Author(s):  
A. Krawiecki
Keyword(s):  
Monte Carlo ◽  
Ising Model ◽  
Monte Carlo Simulations ◽  
Spin Glass ◽  
Phase Diagrams ◽  
Random Graphs ◽  
Second Order ◽  
Ferromagnetic Phase ◽  
Ferromagnetic Transition ◽  
Antiferromagnetic Exchange

Abstract The q-neighbor Ising model is investigated on homogeneous random graphs with a fraction of edges associated randomly with antiferromagnetic exchange integrals and the remaining edges with ferromagnetic ones. It is a nonequilibrium model for the opinion formation in which the agents, represented by two-state spins, change their opinions according to a Metropolis-like algorithm taking into account interactions with only a randomly chosen subset of their q neighbors. Depending on the model parameters in Monte Carlo simulations, phase diagrams are observed with first-order ferromagnetic transition, both first- and second-order ferromagnetic transitions and second-order ferromagnetic and spin-glass-like transitions as the temperature and fraction of antiferromagnetic exchange integrals are varied; in the latter case, the obtained phase diagrams qualitatively resemble those for the dilute spin-glass model. Homogeneous mean-field and pair approximations are extended to take into account the effect of the antiferromagnetic exchange interactions on the ferromagnetic phase transition in the model. For a broad range of parameters, critical temperatures for the first- or second-order ferromagnetic transition predicted by the homogeneous pair approximation show quantitative agreement with those obtained from Monte Carlo simulations; significant differences occur mainly in the vicinity of the tricritical point in which the critical lines for the second-order ferromagnetic and spin-glass-like transitions meet. Graphic abstract

scholarly journals Parameter Estimation and Joint Confidence Regions for the Parameters of the Generalized Lindley Distribution

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Wenhao Gui ◽  
Man Chen
Keyword(s):  
Monte Carlo ◽  
Parameter Estimation ◽  
Monte Carlo Simulations ◽  
Existence And Uniqueness ◽  
Confidence Regions ◽  
Lindley Distribution ◽  
Two Parameters ◽  
Inverse Moment

We deal with the problem of estimating the parameters of the generalized Lindley distribution. Besides the classical estimator, inverse moment and modified inverse estimators are proposed and their properties are investigated. A condition for the existence and uniqueness of the inverse moment and modified inverse estimators of the parameters is established. Monte Carlo simulations are conducted to compare the estimators’ performances. Two methods for constructing joint confidence regions for the two parameters are also proposed and their performances are discussed. A real example is presented to illustrate the proposed methods.

Low-voltage EDS of magnesium ferrite Dendrites in a FEG-SEM

1996 ◽  
Vol 54 ◽  
pp. 478-479
Author(s):  
Matthew T. Johnson ◽  
Ian M. Anderson ◽  
Jim Bentley ◽  
C. Barry Carter
Keyword(s):  
Monte Carlo ◽  
Quantitative Analysis ◽  
Monte Carlo Simulations ◽  
Cross Section ◽  
Spatial Resolution ◽  
Low Voltage ◽  
Magnesium Ferrite ◽  
X Ray ◽  
Interaction Volume ◽  
Ferrite Spinel

Energy-dispersive X-ray spectrometry (EDS) performed at low (≤ 5 kV) accelerating voltages in the SEM has the potential for providing quantitative microanalytical information with a spatial resolution of ∼100 nm. In the present work, EDS analyses were performed on magnesium ferrite spinel [(MgxFe1−x)Fe2O4] dendrites embedded in a MgO matrix, as shown in Fig. 1. spatial resolution of X-ray microanalysis at conventional accelerating voltages is insufficient for the quantitative analysis of these dendrites, which have widths of the order of a few hundred nanometers, without deconvolution of contributions from the MgO matrix. However, Monte Carlo simulations indicate that the interaction volume for MgFe2O4 is ∼150 nm at 3 kV accelerating voltage and therefore sufficient to analyze the dendrites without matrix contributions.Single-crystal {001}-oriented MgO was reacted with hematite (Fe2O3) powder for 6 h at 1450°C in air and furnace cooled. The specimen was then cleaved to expose a clean cross-section suitable for microanalysis.

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