Forward Modeling and Inversion of Direct Current Method for the Damaged Site Detection on the Anticorrosion Coating of Underground Metal Pipeline

2013 ◽  
Vol 411-414 ◽  
pp. 1619-1624
Author(s):  
Xiang Jun Meng ◽  
Huai Shan Liu ◽  
Xun Hua Zhang
Keyword(s):  
Direct Current ◽  
Current Method ◽  
Forward Modeling ◽  
Test Method ◽  
Inversion Method ◽  
Voltage Gradient ◽  
Electrical Method ◽  
Field Source ◽  
Anticorrosion Coating ◽  
And Inversion

Surveying the damaged site on anticorrosion coating of Underground metal pipeline is currently a realistic problem in pipe network construction projects, They are detected through artificial field source method (DC method), including Person method,potential test method,Close interval pipe-to-soil potential survey and Direct Current Voltage Gradient method, but the principle of detecting about electrical method rare mentioned, the article discusses the forward modeling and inversion method of Surveying the specific damaged site on anticorrosion coating of Underground metal pipeline by DC method in great detail, Through calculation and analysis, The authors believe that the DC method is effective in detecting the damaged site on anticorrosion coating of Underground metal pipeline.

Frequency‐domain acoustic‐wave modeling and inversion of crosshole data: Part II—Inversion method, synthetic experiments and real‐data results

Geophysics ◽  
1995 ◽  
Vol 60 (3) ◽  
pp. 796-809 ◽  
Author(s):  
Zhong‐Min Song ◽  
Paul R. Williamson ◽  
R. Gerhard Pratt
Keyword(s):  
Frequency Domain ◽  
Real Data ◽  
Forward Modeling ◽  
Two Dimensions ◽  
Inversion Method ◽  
Inversion Algorithm ◽  
Data Set ◽  
Wave Inversion ◽  
Full Wave ◽  
And Inversion

In full‐wave inversion of seismic data in complex media it is desirable to use finite differences or finite elements for the forward modeling, but such methods are still prohibitively expensive when implemented in 3-D. Full‐wave 2-D inversion schemes are of limited utility even in 2-D media because they do not model 3-D dynamics correctly. Many seismic experiments effectively assume that the geology varies in two dimensions only but generate 3-D (point source) wavefields; that is, they are “two‐and‐one‐half‐dimensional” (2.5-D), and this configuration can be exploited to model 3-D propagation efficiently in such media. We propose a frequency domain full‐wave inversion algorithm which uses a 2.5-D finite difference forward modeling method. The calculated seismogram can be compared directly with real data, which allows the inversion to be iterated. We use a descents‐related method to minimize a least‐squares measure of the wavefield mismatch at the receivers. The acute nonlinearity caused by phase‐wrapping, which corresponds to time‐domain cycle‐skipping, is avoided by the strategy of either starting the inversion using a low frequency component of the data or constructing a starting model using traveltime tomography. The inversion proceeds by stages at successively higher frequencies across the observed bandwidth. The frequency domain is particularly efficient for crosshole configurations and also allows easy incorporation of attenuation, via complex velocities, in both forward modeling and inversion. This also requires the introduction of complex source amplitudes into the inversion as additional unknowns. Synthetic studies show that the iterative scheme enables us to achieve the theoretical maximum resolution for the velocity reconstruction and that strongly attenuative zones can be recovered with reasonable accuracy. Preliminary results from the application of the method to a real data set are also encouraging.

scholarly journals The Application of COMSOL Multiphysics in Direct Current Method Forward Modeling

2011 ◽  
Vol 3 ◽  
pp. 266-272 ◽  
Author(s):  
Xiaolong Wang ◽  
Hui Yue ◽  
Guangliang Liu ◽  
Zhao Zhao
Keyword(s):  
Direct Current ◽  
Current Method ◽  
Forward Modeling ◽  
Comsol Multiphysics

2.5-D forward modeling and inversion of time domain IP method

2017 ◽  
Vol 70 (0) ◽  
pp. 69-79
Author(s):  
Hideki Mizunaga ◽  
Kiyotaka Ishinaga
Keyword(s):  
Time Domain ◽  
Forward Modeling ◽  
And Inversion

Determination of Dipole Spacing in Electrical Landfill Leakage Detection

2010 ◽  
Vol 171-172 ◽  
pp. 171-174
Author(s):  
Hong Cheng ◽  
Peng Kun Liu ◽  
Yu Ling Wang ◽  
Chang Xin Nai
Keyword(s):  
High Voltage ◽  
Direct Current ◽  
Current Method ◽  
Leakage Detection ◽  
High Voltage Direct Current ◽  
The Impact

The dipole spacing can directly affects the detecting sensitivity and accuracy in the landfill leakage detection by the high voltage direct current method. Based on the high voltage DC detecting model, the impact of dipole spacing on locating leaks is analyzed taking a single leak and multiple leaks as example. The results show that the greater the dipole spacing is, the higher the detecting sensitivity is; the smaller the dipole spacing is, the higher the detecting accuracy is. For multiple leaks, only one leak can be located when the dipole spacing is greater than the distance between the two leaks. In order to detect all leaks correctly, the dipole spacing should be smaller than the distance between the two leaks.

Enabling isotropic reflectivity modeling and inversion in anisotropic media

2021 ◽  
Vol 40 (4) ◽  
pp. 267-276
Author(s):  
Peter Mesdag ◽  
Leonardo Quevedo ◽  
Cătălin Tănase
Keyword(s):  
Synthetic Data ◽  
Anisotropic Media ◽  
Forward Modeling ◽  
Seismic Inversion ◽  
Stratified Medium ◽  
Effective Parameters ◽  
Elastic Parameters ◽  
Pp Wave ◽  
Anisotropic Elastic ◽  
And Inversion

Exploration and development of unconventional reservoirs, where fractures and in-situ stresses play a key role, call for improved characterization workflows. Here, we expand on a previously proposed method that makes use of standard isotropic modeling and inversion techniques in anisotropic media. Based on approximations for PP-wave reflection coefficients in orthorhombic media, we build a set of transforms that map the isotropic elastic parameters used in prestack inversion into effective anisotropic elastic parameters. When used in isotropic forward modeling and inversion, these effective parameters accurately mimic the anisotropic reflectivity behavior of the seismic data, thus closing the loop between well-log data and seismic inversion results in the anisotropic case. We show that modeling and inversion of orthorhombic anisotropic media can be achieved by superimposing effective elastic parameters describing the behavior of a horizontally stratified medium and a set of parallel vertical fractures. The process of sequential forward modeling and postinversion analysis is exemplified using synthetic data.

scholarly journals Aerosol microphysical retrievals from Precision Filter Radiometer direct solar radiation measurements and comparison with AERONET

2014 ◽  
Vol 7 (1) ◽  
pp. 99-130 ◽  
Author(s):  
S. Kazadzis ◽  
I. Veselovskii ◽  
V. Amiridis ◽  
J. Gröbner ◽  
A. Suvorina ◽  
...  
Keyword(s):  
Temporal Resolution ◽  
Volume Concentration ◽  
Effective Radius ◽  
Optical Data ◽  
Inversion Method ◽  
High Temporal Resolution ◽  
Random Errors ◽  
Percentage Difference ◽  
Filter Radiometer ◽  
And Inversion

Abstract. Synchronized sun-photometric measurements from the AERONET-CIMEL and GAW-PFR aerosol networks are used to compare retrievals of the aerosol optical depth, effective radius and volume concentration during a high temporal resolution measurement campaign at the Athens site in the Mediterranean Basin from 14–22 July 2009. During this period, direct sun AOD retrievals from both instruments exhibited small differences in the range 0.01–0.02 despite the presence of a strong dust event. In addition to AERONET-CIMEL inversion data, an independent inversion method was applied that involves expanding the particle size distribution in terms of measurement kernels so as to estimate bulk particle parameters from a linear-estimated combination of the input optical data. AOD measurements obtained from both CIMEL and PFR instruments using this method also showed reasonable agreement. For low aerosol loads (AOD < 0.2), measurements of the effective radius by the PFR were found to be −20% to +30% different from CIMEL values for both direct sun data and inversion data. At higher loads (AOD > 0.4), measurements of the effective radius by the PFR are consistently 20% lower than CIMEL for both direct sun and inversion data. Volume concentrations at low aerosol loads from the PFR are up to 80% higher than the CIMEL for direct sun data, but inversion data suggests that volume concentrations from the PFR are up to 20% lower than the CIMEL under these same conditions. At higher loads, the percentage difference in volume concentrations from the PFR and CIMEL is systematically negative with inversion data predicting differences 30% lower than those obtained from direct sun data. An assessment of the effect of errors in the AOD retrieval on the estimation of PFR bulk parameters was made using Monte Carlo simulations and demonstrated that it is possible to estimate the effective radius with an uncertainty below 60% and the volume concentration with an uncertainty below 65% even when AOD < 0.2 and when the input errors are as high as 10%. Highlights – A comparison of high temporal resolution synchronous CIMEL and PFR direct sun AOD measurement retrievals – Calculation of bulk aerosol microphysics parameters using a linear estimation inversion technique – A comparison of retrieved aerosol volume concentrations and effective radii from CIMEL and PFR inversions – An analysis of the sensitivity of PFR retrievals to random errors on the optical input data

scholarly journals Pemisahan Anomali Regional-Residual pada Metode Gravitasi Menggunakan Metode Moving Average, Polynomial dan Inversion

2016 ◽  
Vol 3 (01) ◽  
pp. 10 ◽  
Author(s):  
Jarot Purnomo ◽  
Sorja Koesuma ◽  
Mohtar Yunianto
Keyword(s):  
Average Method ◽  
Moving Average ◽  
Continuation Method ◽  
Inversion Method ◽  
Polynomial Method ◽  
Minimum Error ◽  
Gravity Method ◽  
Upward Continuation ◽  
And Inversion ◽  
Separation Results

<span>It has been done a research about separation of regional-residual anomaly in Gravity method. <span>This research compares the result of three methods i.e. moving average method, polynomial <span>method, and inversion method. The computer program is created using a computer programming <span>Matlab 7. From three methods that have been made, the separation results are compared with<br /><span>results of separation by using Upward Continuation method. From the results of these <span>comparisons will be available an excellent program of regional-residual anomali separation. The <span>results show that in polynomial method of the order 4 obtained similar contour to the separation <span>by Upward Continuation Software. So that the output of this separation will be treated again <span>with Grav2DC software. The output of this software is the density of rock Grav2DC of the study<br /><span>area. Processing results obtained the minimum error of 1.85% for the separation by polynomial <span>method, while for the method of Upward Continuation obtained minimum error of 2.22%. The <span>results obtained show that the separation of regional-residual anomali by polynomial method is <span>similar to separation by Upward Continuation method.</span></span></span></span></span></span></span></span></span></span></span></span><br /></span>

Sign in / Sign up

Export Citation Format

Share Document