Q-factor determitation with seismoacoustis well logs for estimation of distribution of inhomogeneities in artificial grounds

2020 ◽  
pp. 87-91
Author(s):  
D. V. Shmurak
Keyword(s):  
Quality Control ◽  
Frequency Shift ◽  
Well Logs ◽  
Q Factor ◽  
Amplitude Ratios ◽  
Shift Method ◽  
Additional Information ◽  
Jet Grouting ◽  
Estimation Of Distribution ◽  
I Factor

Quality control in geotechnical engineering is becoming an important issue, especially when products are buried underground. Seismoacoustic methods are widely used for investigations in such structures. In this article seismoacoustic well logs from hidden structures (made by jet grouting technology) are being processed with the goal of obtaining additional information about distribution of heterogeneities in improves grounds. Two methods of estimation Q-factor are used: frequency shift method and amplitude ratios method.

scholarly journals Quality factor estimation based on the peak frequency shift method using a robust Fourier transform to VSP data

2019 ◽  
Vol 16 (6) ◽  
pp. 1061-1070 ◽  
Author(s):  
Rómulo Sandoval ◽  
José L Paredes ◽  
Flor A Vivas
Keyword(s):  
Fourier Transform ◽  
Frequency Shift ◽  
Quality Factor ◽  
Peak Frequency ◽  
Estimation Methods ◽  
Signal Spectrum ◽  
Q Factor ◽  
Shift Method ◽  
Vsp Data ◽  
Factor Estimation

Abstract Quality factor estimation (Q estimation) of vertical seismic profile (VSP) data are necessary for the process referred to as inverse Q-filtering, which is used, in turn, to improve the resolution of seismic signals. In general, the performances of Q estimation methods, based on the standard Fourier transform, are severely degraded in the presence of heavy-tailed distributed noise. In particular, these methods require a bandwidth detection which is difficult to estimate due to instabilities caused by outliers or gross errors, leading to an incorrect Q estimation. In this paper, an improvement of the Q-factor estimation based on the peak frequency shift method is proposed, where the signal spectrum is obtained using a robust transform algorithm. More precisely, the robust transform method assumes that the perturbations that contaminate the signal of interest can be characterized as random samples following a zero-mean Laplacian distribution, leading to the weighted median as the optimal operator for determining each transform coefficient. The proposed method is validated on synthetic datasets using different levels of noise and its performance is compared to those yielded by various methods based on the standard Fourier transform. Furthermore, a non-Gaussianity test is performed in order to characterize the noise distribution in real data. From the non-Gaussianity test, it can be observed that the underlying noise is better characterized using a Laplacian statistical model, and therefore, the proposed method is a suitable approach for computing the Q factor. Finally, the proposed methodology is applied to estimate the Q factors of real VSP data.

scholarly journals Proteasome and thiol involvement in quality control of glycosylphosphatidylinositol anchor addition

1998 ◽  
Vol 332 (1) ◽  
pp. 111-118 ◽  
Author(s):  
Barry WILBOURN ◽  
Darren N. NESBETH ◽  
Linda J. WAINWRIGHT ◽  
Mark C. FIELD
Keyword(s):  
Quality Control ◽  
Cysteine Residue ◽  
Retention Mechanism ◽  
Secretory Proteins ◽  
Aggregate Formation ◽  
Er Quality Control ◽  
Additional Information ◽  
Intracellular Degradation ◽  
Processing Signal ◽  
Ubiquitination System

Improperly processed secretory proteins are degraded by a hydrolytic system that is associated with the endoplasmic reticulum (ER) and appears to involve re-export of lumenal proteins into the cytoplasm for ultimate degradation by the proteasome. The chimaeric protein hGHDAF28, which contains a crippled glycosylphosphatidylinositol (GPI) C-terminal signal peptide, is degraded by a pathway highly similar to that for other ER-retained proteins and is characterized by formation of disulphide-linked aggregates, failure to reach the Golgi complex and intracellular degradation with a half life of ∼ 2 h. Here we show that N-acetyl-leucinal-leucinal-norleucinal, MG-132 and lactacystin, all inhibitors of the proteasome, protect hGHDAF28; hGHDAF28 is still proteolytically cleaved in the presence of lactacystin or MG-132, by the removal of ∼ 2 kDa, but the truncated fragment is not processed further. We demonstrate that the ubiquitination system accelerates ER-degradation of hGHDAF28, but is not essential to the process. Overall, these findings indicate that GPI quality control is mediated by the cytoplasmic proteasome. We also show that the presence of a cysteine residue in the GPI signal of hGHDAF28 is required for retention and degradation, as mutation of this residue to serine results in secretion of the fusion protein, implicating thiol-mediated retention as a mechanism for quality control of some GPI signals. Removal of the cysteine also prevents inclusion of hGHDAF28 in disulphide-linked aggregates, indicating that aggregate formation is an additional retention mechanism for this class of protein. Therefore our data suggest that an unpaired terminal cysteine is the retention motif of the hGHDAF28 GPI-processing signal and that additional information may be required for efficient engagement of ER quality control systems by the majority of GPI signals which lack cysteine residues.

Investigation on Resonance Effects of Closely Resonating Nano-Pillars Attached to SAW Resonator

2011 ◽  
Vol 403-408 ◽  
pp. 1183-1187
Author(s):  
N. Ramakrishnan ◽  
Harshal B. Nemade ◽  
Roy Paily Palathinkal
Keyword(s):  
Acoustic Wave ◽  
Resonance Frequency ◽  
Frequency Shift ◽  
Fem Simulation ◽  
Mass Loading ◽  
Loading Effect ◽  
Resonance Effects ◽  
Additional Information ◽  
Resonance Frequency Shift ◽  
Small Change

Surface acoustic wave (SAW) sensors form an important class of micro sensors in the microelecto mechanical systems (MEMS) family. Mass loading effect of a sensing medium is one of the prime sensing principles in SAW sensors. Recently we reported mass loading effect of high aspect ratio nano-pillars attached to a SAW resonator. We observed increase in resonance frequency of the SAW resonator in addition to the general mass loading characteristics. We concluded that when the resonance frequency of the pillar is equal to the SAW resonator frequency, the resonance frequency shift caused by mass loading of pillar tends to a negligible value. When such resonating pillars are used as sensing medium in SAW sensors, even a very small change in the dimension of the pillar will offer significant resonance frequency shift. Accordingly, high sensitive SAW sensors can be developed. However in practice it’s quite difficult to manufacture nano-pillars with accurate dimensions such that they resonate with SAW resonator. There is more probability that the pillars may closely resonate with SAW device and offer mass loading. In the present work we have extended our earlier work and performed finite element method (FEM) simulation to study the insight physics of the closely resonating pillars and their effects on acoustic wave propagating on SAW substrate. In this paper we present the discussion on the resonance effects of typical closely resonating pillars on resonance frequency spectrum of the SAW resonator and observations in the pressure wave at the contact surface of the pillar and SAW resonator substrate. It is observed that when the nano-pillars closely resonate with SAW resonator, the pillar oscillations combine with waves propagating in the substrate and introduce beat frequencies. The results and discussion of this paper adds additional information in designing SAW based coupled resonating systems.

scholarly journals ACOUSTIC SEISMIC WAVE ATTENUATION IN ROCKS: ESTIMATES INSTABILITIES, FREQUENCY-DEPENDENCE AND INCOHERENCES

2017 ◽  
Vol 35 (3) ◽  
Author(s):  
Julián David Peláez ◽  
Luis Alfredo Montes
Keyword(s):  
Frequency Shift ◽  
Seismic Wave ◽  
Wave Attenuation ◽  
Spectral Ratio ◽  
Well Logs ◽  
Well Log ◽  
Seismic Profiles ◽  
Seismic Wave Attenuation ◽  
Transmission Coefficients ◽  
Centroid Frequency

ABSTRACT. Seismic wave attenuation (Q−1) values indicate relevant media properties, such as fluid content and porosity. Q−1 estimates, obtained using both VSP and conventional well log data, did not exhibit comparable trends, nor values. Whereas VSP results represent total attenuation, well log Q−1, which, theoretically, should represent scattering losses, displayed a low percentage correlation with transmission coefficients and other well logs. The influence of processing routines, chosen methodology and input parameters on Q−1-values suggests that ASR (Amplitude Spectral Ratio) and CFS (Centroid Frequency Shift) attenuation estimates should be regarded, in practical terms, as relative quantities instead of absolute ones. Seemingly incoherent negative values are frequent, nonetheless these could hold a physical meaning related to elastic amplification at interfaces. Considering that quality factor (Q) values obtained were more unstable than Q−1-values, it is advisable to report the latter. Keywords: Vertical Seismic Profiles, well logs, transmission coefficients, scattering, amplification.RESUMO. Os valores de atenuação da onda sísmica (Q−1) indicam propriedades relavantes dos meios, tais como conteúdo de fluido e porosidade. As estimativas do Q−1, obtidas usando dados de VSP e dados de poços convencionais, não apresentaram tendências nem valores comparáveis. Enquanto os resultados de VSP representamatenuação total, os resultados dos dados de poços, que teoricamente deveriam representar perdas de dispersão, apresentaramuma baixa correlação percentual com os coeficientes de transmissão e outros dados de poços. A influência das rotinas de processamento, da metodologia escolhida e dos parâmetros de entrada nos valores Q−1 sugere que as estimativas de atenuação ASR (Amplitude Spectral Ratio) e CFS (Centroid Frequency Shift) devem ser, em termos práticos, consideradas como quantidades relativas em vez de absolutas. Valores negativos aparentemente incoerentes são frequentes, no entanto estes poderiam conter um significado físico relacionado `a amplificação elástica nas interfaces. Considerando que os valores do fator de qualidade (Q) obtidos foram mais instáveis do que os valores de Q−1, é aconselhável documentar o último. Palavras-chave: Perfis Sísmicos Verticais, registros de poços, coeficientes de transmissão, dispersão, amplificação.

scholarly journals Rapid Deconvolution of Low-Resolution Time-of-Flight Data using Bayesian Inference

2019 ◽  
Author(s):  
Cornelius Pieterse ◽  
Michiel B. De Kock ◽  
Wesley D. Robertson ◽  
Hans C. Eggers ◽  
R. J. Dwayne Miller
Keyword(s):  
Time Of Flight ◽  
Stopping Criterion ◽  
Amplitude Ratios ◽  
Resolution Time ◽  
Low Resolution ◽  
Flight Data ◽  
Additional Information ◽  
Bayesian Prior ◽  
Accurate Quantification ◽  
General Method

Deconvolution of low-resolution time-of-flight data has numerous advantages including the ability to extract additional information from the experimental data. We augment the well-known Lucy-Richardson deconvolution algorithm by various Bayesian prior distributions and show that a prior of second-differences of the signal outperforms the standard Lucy-Richardson algorithm, accelerating the rate of convergence by more than a factor of four, while preserving the peak amplitude ratios of a similar fraction of the total peaks. A novel stopping criterion and boosting mechanism is implemented to ensure these methods converge to a similar entropy, and that local minima are avoided, respectively. Improvement by a factor of two in mass resolution allows more accurate quantification of the spectra. The general method is demonstrated in this paper by the deconvolution of fragmentation peaks of the DHB matrix, as well as the BTP thermometer ion, following femtosecond ultraviolet laser desorption.

Qestimation from reflection seismic data for hydrocarbon detection using a modified frequency shift method

2015 ◽  
Vol 12 (4) ◽  
pp. 577-586 ◽  
Author(s):  
Fangyu Li ◽  
Huailai Zhou ◽  
Nan Jiang ◽  
Jianxia Bi ◽  
Kurt J Marfurt
Keyword(s):  
Frequency Shift ◽  
Seismic Data ◽  
Shift Method ◽  
Hydrocarbon Detection ◽  
Reflection Seismic
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