Iterative determination of permittivity and conductivity profiles of a dielectric slab in the time domain

1981 ◽  
Vol 29 (2) ◽  
pp. 239-245 ◽  
Author(s):  
A. Tijhuis
Keyword(s):  
Time Domain ◽  
Dielectric Slab ◽  
The Time Domain

scholarly journals Distribution of Characteristic Times: A High-Resolution Spectrum Approach for Visualizing Chemical Relaxation and Resolving Kinetic Parameters of Ionic-Electronic Conducting Ceramic Oxides

Coatings ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1240
Author(s):  
Fuyao Yan ◽  
Yiheng Wang ◽  
Ying Yang ◽  
Lei Zhu ◽  
Hui Hu ◽  
...  
Keyword(s):  
Kinetic Parameters ◽  
Time Domain ◽  
Bulk Diffusion ◽  
High Resolution Spectrum ◽  
Surface Exchange ◽  
Ceramic Oxides ◽  
Fitting Procedure ◽  
The Time Domain ◽  
Rate Limiting

Surface exchange coefficient (k) and bulk diffusion coefficient (D) are important properties to evaluate the performance of mixed ionic-electronic conducting (MIEC) ceramic oxides for use in energy conversion devices, such as solid oxide fuel cells. The values of k and D are usually estimated by a non-linear curve fitting procedure based on electrical conductivity relaxation (ECR) measurement. However, the rate-limiting mechanism (or the availability of k and D) and the experimental imperfections (such as flush delay for gaseous composition change, τf) are not reflected explicitly in the time–domain ECR data, and the accuracy of k and D demands a careful sensitivity analysis of the fitting error. Here, the distribution of characteristic times (DCT) converted from time–domain ECR data is proposed to overcome the above challenges. It is demonstrated that, from the DCT spectrum, the rate-limiting mechanism and the effect of τf are easily recognized, and the values of k, D and τf can be determined conjunctly. A strong robustness of determination of k and D is verified using noise-containing ECR data. The DCT spectrum opens up a way towards visible and credible determination of kinetic parameters of MIEC ceramic oxides.

On the Evaluation of Dynamic Stresses in Pipelines Using Limited Vibration Measurements and FEA in the Time Domain

1999 ◽  
Vol 121 (1) ◽  
pp. 37-41 ◽  
Author(s):  
W. A. Moussa ◽  
A. N. AbdelHamid
Keyword(s):  
Time Domain ◽  
Minimum Distance ◽  
Exciting Force ◽  
Vibration Measurement ◽  
Dynamic Stresses ◽  
Vibration Measurements ◽  
Pipe Model ◽  
Related Risk ◽  
The Time Domain

A practical technique is investigated for the determination of dynamic stresses in pipelines through the use of finite element method (FEM) and field measurement vibrations at selected points. Numerical simulation of a randomly loaded pipeline structure is used to establish the validity of the technique in the time domain. The analysis is carried out for a fixed-hinged pipe model. The results show that lack of coincidence between the vibration measurement points (VMPs) and the exciting force, or the use of only translational vibration measurements (TVMs) produce an approximate stress picture. The extent of the “error” in these cases is found to depend on the density of the VMPs and the proximity between these points and the exciting force location. A safety-related risk assessment is applied to find the minimum distance between measuring points that is needed to meet design codes reliability specifications.

scholarly journals Determination of Mount Merapi Volcanic Earthquake Hypocentre By Using Seismic Wave Polarization Analysis

2020 ◽  
Vol 1 (1) ◽  
pp. 21
Author(s):  
Syahrial Ayub ◽  
Muhammad Zuhdi ◽  
Muhammad Taufik ◽  
Gunawan Gunawan
Keyword(s):  
Frequency Domain ◽  
Time Domain ◽  
Volcanic Earthquake ◽  
Wave Polarization ◽  
Polarization Analysis ◽  
Space Domain ◽  
Volcanic Earthquakes ◽  
Hypocenter Determination ◽  
The Time Domain

Volcanic earthquakes of mount Merapi have been investigated periodically. The investigation aims to determine the hypocenter and epicenter of mount Merapi's volcanic earthquake using wave polarization analysis. The analysis was carried out in three domains, which are the time domain, the frequency domain, and the space domain. The analysis in the time domain was conducted by the arrival time of the volcanic earthquake, and the analysis in the frequency domain was done by observing the spectrum to get information on source frequency and bandwidth passed from polarization analysis, while the analysis in the space domain was conducted especially on hypocenter determination of the volcanic earthquakes. The analysis leads to the frequency of source 6 Hz and a bandwidth of 0.1 Hz. Thus, the hypocenter of volcanic earthquakes by polarization analysis was distributed to depth from 670 m to 3250 m from Merapi's top

scholarly journals Determination of the response of a class of nonlinear time invariant systems

1981 ◽  
Vol 4 (3) ◽  
pp. 615-623
Author(s):  
Sudhangshu B. Karmakar
Keyword(s):  
Frequency Domain ◽  
Time Domain ◽  
Inverse Laplace Transform ◽  
New Approach ◽  
Functional Expansion ◽  
Expansion Time ◽  
Time Domain Response ◽  
The Time Domain ◽  
Time Invariant

This paper illustrates by means of a simple example a new approach for the determination of the time domain response of a class of nonlinear systems. The system under investigation is assumed to be described by a nonlinear differential equation with forcing term. The response of the system is first obtained in terms of the input in the form of a Volterra functional expansion. Each of the components in the expansion is first transformed into a multidimensional frequency domain and then to a single dimensional frequency domain by the technique of association of variables. By taking into consideration the conditions for the rapid convergence of the functional expansion the response of the system in the frequency domain can effectively be obtained by taking only the first few terms of the expansion. Time domain response is then found by inverse Laplace transform.

Time-Domain Poroelastic Green's Functions

2003 ◽  
Vol 11 (03) ◽  
pp. 491-501 ◽  
Author(s):  
Andrzej Hanyga
Keyword(s):  
Differential Equations ◽  
Asymptotic Solution ◽  
Time Domain ◽  
Green's Functions ◽  
Green’S Functions ◽  
Isotropic Case ◽  
The Time Domain ◽  
Singular Memory ◽  
Asymptotic Time

A method previously developed for asymptotic solution of systems of integro-differential equations with singular memory is applied to the determination of the time-domain asymptotic Green's function of Biot's poroelasticity. Asymptotic time-domain Green's functions are constructed in a neighborhood of the wavefronts. The general anisotropic medium as well as the isotropic case are considered.

Determination of Transition Jitter Noise by Time Domain Analysis

2015 ◽  
Vol 781 ◽  
pp. 231-234
Author(s):  
Komkrit Chooruang
Keyword(s):  
Time Domain ◽  
Linear Density ◽  
Time Domain Analysis ◽  
Domain Analysis ◽  
Maximum Point ◽  
Perpendicular Media ◽  
Work Transition ◽  
Transition Jitter ◽  
The Time Domain

Transition jitter noise can be caused by a variety of factors such as contributions by the medium, head, and drive electronics. In this work, transition jitter noise in magnetic recording is measured based on the time domain analysis. An example of transition jitter noise in perpendicular media is investigated using captured noisy replay signals compare with a reconstructed ideal signal. It is found that transition noise increased with increasing linear density and dropped sharply after the maximum point.

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