The SHEW technique as a simple method to characterize the non-linear properties of crystals: investigation of helium implantation effects in LiNbO3 and KTiOPO4

2001 ◽  
Vol 16 (1-2) ◽  
pp. 125-130 ◽  
Author(s):  
R. Kremer ◽  
P. Bindner ◽  
A. Boudrioua ◽  
P. Moretti ◽  
J.C. Loulergue
Keyword(s):  
Simple Method ◽  
Non Linear ◽  
Helium Implantation

scholarly journals Experimental Evaluation of Distortion in Amplitude Modulation Techniques for Parametric Loudspeakers

2020 ◽  
Vol 10 (6) ◽  
pp. 2070
Author(s):  
Ricardo San Martín ◽  
Pablo Tello ◽  
Ana Valencia ◽  
Asier Marzo
Keyword(s):  
Frequency Response ◽  
Amplitude Modulation ◽  
Experimental Evaluation ◽  
Harmonic Distortion ◽  
Intermodulation Distortion ◽  
Simple Method ◽  
Modulation Techniques ◽  
Audible Sound ◽  
Non Linear

Parametric loudspeakers can generate a highly directional beam of sound, having applications in targeted audio delivery. Audible sound modulated into an ultrasonic carrier will get self-demodulated along the highly directive beam due to the non-linearity of air. This non-linear demodularization should be compensated to reduce audio distortion, different amplitude modulation techniques have been developed during the last years. However, some studies are only theoretical whereas others do not analyze the audio distortion in depth. Here, we present a detailed experimental evaluation of the frequency response, harmonic distortion and intermodulation distortion for various amplitude modulation techniques applied with different indices of modulation. We used a simple method to measure the audible signal that prevents the saturation of the microphones when the high levels of the ultrasonic carrier are present. This work could be useful for selecting predistortion techniques and indices of modulation for regular parametric arrays.

scholarly journals SIMPLE METHOD FOR MEASUREMENT OF NON-LINEAR LATERAL SOIL SPRING WITH CONSIDERATION OF EFFECT OF PILE ARRANGEMENT

2012 ◽  
Vol 77 (676) ◽  
pp. 877-882
Author(s):  
Nobuhide NARITA ◽  
Osamu KANEKO ◽  
Hisashi NEMOTO ◽  
Shigeo KANAI ◽  
Toshiaki ARAI
Keyword(s):  
Simple Method ◽  
Non Linear ◽  
Pile Arrangement

Turbulent Heat Transfer in a Backward-Facing Step Flow Using a Non-Linear k-ε Model

2002 ◽  
Author(s):  
Marcelo Assato ◽  
Marcelo J. S. de Lemos
Keyword(s):  
Heat Transfer ◽  
Turbulent Heat Transfer ◽  
Turbulent Heat ◽  
Backward Facing Step ◽  
Simple Method ◽  
Wall Functions ◽  
Non Linear ◽  
Standard Linear ◽  
Experimental Values ◽  
Better Than

This work presents numerical results for heat transfer in turbulent flow past a backward-facing step. It is shown that nonlinear k-ε models perform better than their linear counterparts when simulations are compared with experimental values. Wall functions are used for simplicity of the simulations. The finite-volume technique is employed for discretizing the transport equation set on a non-orthogonal grid system. The SIMPLE method is used for correcting the pressure field. Results for the reattachment length using the non-linear model are closer to the experimental values when compared with similar calculations using the standard linear closure.

Modelling of ballraceway contacts in a slewing bearing with non-linear springs

2011 ◽  
Vol 225 (4) ◽  
pp. 827-831 ◽  
Author(s):  
X H Gao ◽  
X D Huang ◽  
H Wang ◽  
J Chen
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Contact Area ◽  
The Finite Element Method ◽  
Simple Method ◽  
Slewing Bearing ◽  
Combined Loads ◽  
Non Linear ◽  
The Difference ◽  
Supporting Structures

During the operation, a slewing bearing is always subjected to a set of combined loads. It is the source of deformation of ballraceway contacts, rings, and even supporting structures. In practice, deformation of rings and supporting structures is often neglected for simplification, that is, they are supposed to be ideally stiff. To take elasticity of rings and supporting (fixed) structures into consideration, the finite-element method (FEM) is applied. Due to hundreds of contact pairs and the difference in the scale of contact area and rings or supporting structures, it is difficult to simultaneously model both local ballraceway contacts and the global slewing rings in a slewing bearing. The article developed a simple method to solve the problem, where the contacts are replaced by non-linear springs.

scholarly journals Dynamics of dark energy in collapsing halo of dark matter

2015 ◽  
Vol 5 (1) ◽  
pp. 51-56 ◽  
Author(s):  
M. Tsizh ◽  
B. Novosyadlyj
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Large Scale ◽  
Einstein Equations ◽  
Linear Stage ◽  
Expanding Universe ◽  
Simple Method ◽  
Linear Evolution ◽  
Non Linear ◽  
Linear Differential

We investigate the non-linear evolution of spherical density and velocity perturbations of dark matter and dark energy in the expanding Universe. For this we have used the conservation and Einstein equations to describe the evolution of gravitationally coupled inhomogeneities of dark matter, dark energy and radiation from the linear stage in the early Universe to the non-linear stage at the current epoch. A simple method of numerical integration of the system of non-linear differential equations for evolution of the central part of halo is proposed. The results are presented for the halo of cluster (k=2 Mpc-1) and supercluster scales (k=0.2 Mpc-1) and show that a quintessential scalar field dark energy with a low value of effective speed of sound cs<0.1 can have a notable impact on the formation of large-scale structures in the expanding Universe.

Fuzzy Number Approximation

1998 ◽  
Vol 06 (01) ◽  
pp. 69-78 ◽  
Author(s):  
Mariano Jiménez ◽  
Juan Antonio Rivas
Keyword(s):  
Initial Data ◽  
Economic Model ◽  
Fuzzy Number ◽  
Fuzzy Numbers ◽  
Triangular Fuzzy Number ◽  
Membership Functions ◽  
Simple Method ◽  
Non Linear

As the number of parameters involved in an economic model is often uncertain, we propose that it be estimated using fuzzy numbers. Since we move in an environment of uncertainty, it is logical to leave room for deviation in estimating membership functions. We should recall that when soft max-min operators are used, the resulting deviation is never greater than the variation introduced in estimating the initial data. Often, the result of our calculations is not a triangular fuzzy number. In this paper we study the value of approximating the resulting non-linear fuzzy number using a triangular fuzzy number having the same support and kernel. Finally, we present a simple method for weighing this approximation.

scholarly journals Bentonite and Magnetite Filler-Modified Polyurethane Foam in Fixed Bed Column for the Adsorption of Mercury(II) Ions from Aqueous Solution

2021 ◽  
Vol 10 (1) ◽  
pp. 27-36
Author(s):  
Siti Sarah ◽  
Adisalamun Adisalamun ◽  
Darmadi Darmadi ◽  
Suraiya Kamaruzzaman ◽  
Abrar Muslim ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Adsorption Isotherm ◽  
Adsorption Capacity ◽  
Polyurethane Foam ◽  
Pore Volume ◽  
Linear Models ◽  
Removal Rate ◽  
Fixed Bed ◽  
Simple Method ◽  
Non Linear

This paper proposed adsorbent development by synthesizing polyurethane foam (PUF) using a simple method, mixing polyol with isocyanate and adding fillers of bentonite and magnetite to the PUF matrix. The study's main objective was to produce a PUF-based adsorbent with high reactivity to remove Hg2+ in wastewater. This bentonite and magnetite filler-modified polyurethane foam (BMPUF) adsorbent was fixed in a bed column for the adsorption of mercury (II) ions from an aqueous solution. The effect of initial Hg2+ concentration on the removal rate and the effect of contact time on adsorption efficiency was investigated. Langmuir, Freundlich, and BET non-linear models were taken into account to determine the best adsorption isotherm fitting and obtain adsorption capacity, intensity, and pore volume. As a result, it followed the non-linear Freundlich model, and the average adsorption capacity and intensity were 0.466 mg/g and 0.923, respectively. The average BET-based pore volume obtained was 0.782 L/mg. The kinetics study showed that the non-linear pseudo-first-order kinetics model was more suitable for describing the Hg2+ adsorption kinetics. The maximum equilibrium adsorption capacity was 1.770 mg/g with the adsorption rate of 0.0013 min-1 based on the non-linear model. The effect of varying bentonite and magnetite ratio on adsorption isotherm and kinetics was also investigated. Overall, the potential application of BMPUF adsorbent in the adsorption of mercury (II) ions was demonstrated in the current study. 

A Method for Ultimate Strength Assessment of Plates in Combined Stresses

2015 ◽  
Author(s):  
Shengming Zhang ◽  
Lei Jiang
Keyword(s):  
Ultimate Strength ◽  
Structural Engineering ◽  
Fe Analysis ◽  
Strength Analysis ◽  
Element Analysis ◽  
Simple Method ◽  
Strength Assessment ◽  
Industry Standards ◽  
Non Linear ◽  
Offshore Industry

It is becoming a normal practice in structural engineering, including ships and offshore industry, to perform non-linear finite element analysis to assess the structure’s capacity for design or evaluation purposes. However, experience has shown that the quality and accuracy of the non-linear FE analysis results are highly dependent on the person’s skills and analysis procedures used. In some cases, the results could lead to a wrong conclusion. Simplified method with good accuracy is still a preferred approach in design by the industry because it is simple and easy to use. However, even the method for the simple model, a plate under combined loads, has not been addressed completely because of its complexity. This paper has thus developed a simple method for the ultimate strength analysis of square plates under combined longitudinal and transverse compressive stresses. The method is fully validated with a systematic non-linear FE analysis results. The paper has also compared the methods from the industry standards BS5400 and DIN18800. Analysis examples are also provided in the paper for reference and discussions.

A simple method to produce quasi-simultaneous multiple-energy helium implantation

1983 ◽  
Vol 114 (2-3) ◽  
pp. 330-333 ◽  
Author(s):  
F. Pászti ◽  
M. Fried ◽  
A. Manuaba ◽  
G. Mezey ◽  
E. Kótai ◽  
...  
Keyword(s):  
Simple Method ◽  
Helium Implantation
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