Leak Detection for City Gas Pipelines Based on Instantaneous Energy Distribution Characteristics

2010 ◽  
Author(s):  
Zhigang Chen
Keyword(s):  
Energy Distribution ◽  
Distribution Characteristics ◽  
Physical Relationship ◽  
Correlative Analysis ◽  
Relative Contribution ◽  
Input And Output ◽  
City Gas ◽  
State Variation ◽  
Characteristic Signal ◽  
Instantaneous Energy

Because of the smallness of flux and low of pressure it is difficult to judge the characteristic signal when leak occurs. In this paper, a new instantaneous energy (IE) distribution characteristics extraction method based on Hilbert-Huang transformation (HHT) was presented and it was used to recognize different states in pipelines, such as, normal state, valve operating, compressor operating and leak. Firstly, the physical relationship between instantaneous energy and structural state variation of a system was analyzed theoretically. With HHT, the instantaneous energy distribution feature of an unstable pressure signal was obtained, according to the relative contribution method of the instantaneous energy, its noise was eliminated. In order to judge the leak the typical character of the instantaneous energy of pressure in the input and output ends was discussed using correlative analysis. The experimental results showed that this method is effective.

scholarly journals Climate, landscape and vegetation controls of behavioral catchments on dominant runoff response and catchment travel time distribution

2021 ◽  
Author(s):  
Chatchai Jothityangkoon ◽  
Haruetai Maskong
Keyword(s):  
Travel Time ◽  
Overland Flow ◽  
Theoretical Perspective ◽  
Hydrologic Model ◽  
Runoff Generation ◽  
Catchment Scale ◽  
Physical Relationship ◽  
Relative Contribution ◽  
Hillslope Scale ◽  
The Impact

The three dominant processes contributing to runoff as proposed by the Dunne diagram are Hortonian overland flow (HOF), Dunne overland flow (DOF) and subsurface storm flow (SSF). Using a theoretical perspective, we investigate the impact of climate, soil, topography and vegetation on catchment water balance and the probability distribution of the travel times of each runoff generation component in respect of the connected instantaneous response function (CIRF) including the interaction of a partial contributing area connecting to the outlet. A simple distributed hydrologic model is used to capture the effect of the catchment response and to estimate the CIRFs under different possible integration of combined effect of climate, soil, topography and vegetation. A set of dimensionless similarity parameters represent catchment functions and provide a quantitative explanation of the conceptual Dunne diagram. Behavioral catchments are defined from the empirical range of the Budyko curve and mainly compatible to the physical relationship as illustrated in the Dunne diagram. The results consistent with the Dunne diagram are: (1) DOF and SSF dominates in humid for behavioral sand and silt catchments, (2) HOF dominates in arid for behavioral silt and clay catchments. Inconsistent results are: (1) SSF dominates in arid for behavioral sand, silt and clay catchments, (2) HOF dominates in humid for behavioral clay catchment and (3) no dominant HOF for behavioral sand catchment. For HOF and DOF dominates, the distribution of CIRFs can be grouped into similar shapes, which depend on the relative contribution of hillslope scale and catchment scale. For SSF behavioral catchments, the shape of the CIRFs depends on the dryness index. The combined catchment CIRFs of mean travel time for runoff responses consists with the higher first peak from the HOF and/or DOF and the second peak from the SSF.

scholarly journals Characteristics of the elemental compositions of particulate matter at a subway platform using INAA and XRF

2011 ◽  
Vol 1 (1) ◽  
pp. 313-318
Author(s):  
J. M. Lim ◽  
J. H. Jeong ◽  
B. W. Jung ◽  
J. H. Lee ◽  
J. H. Moon ◽  
...  
Keyword(s):  
Enrichment Factors ◽  
Subway Station ◽  
Distribution Characteristics ◽  
Particle Fraction ◽  
Absolute Concentration ◽  
Average Standard Deviation ◽  
Relative Contribution ◽  
Pm2.5 And Pm10 ◽  
Crustal Enrichment Factors ◽  
Concentration Levels

Abstract In this study, a total of 21 elements were determined from PM2.5 and PM10 samples collected at one subway station using INAA and XRF. In order to assess the pollution status and distribution characteristics in a subway station, the absolute concentration levels, concentration ratios, and crustal enrichment factors of these elements were analyzed. PM2.5 concentrations in the subway station varied in the range of 24.8 to 72.6 μg m−3 (average  ±  standard deviation: 42.6 ± 10.6 μg m−3), while those of PM10 from 38.0 to 101 μg m−3 (67.2 ± 15.5 μg m−3). The relative contribution of elemental components in each particle fraction accounted for about 42 and 44%, respectively. Out of all metals, Fe was predominant to represent about 29 and 27% of each particle fraction. In contrast, the crustal sources were estimated to contribute to about 3.7 and 2.3% of the total Fe concentrations, respectively. Thus, one can conclude that considerable quantities of airborne Fe particles originated mainly from subway sources, probably due to the wearing of the steel products like wheel, rail, brake, etc.

An Investigation of Tooth Wear Diagnosis of Gear Based on Process Systems Modeling

2012 ◽  
Vol 549 ◽  
pp. 834-838
Author(s):  
Feng Li Wang ◽  
Hui Xing
Keyword(s):  
Energy Distribution ◽  
Frequency Spectrum ◽  
Frequency Analysis ◽  
Vibration Signal ◽  
Tooth Wear ◽  
Time Frequency Analysis ◽  
Time Frequency ◽  
Gear Fault ◽  
Local Wave ◽  
Instantaneous Energy

Targeting the advantages of local wave analysis(LWA) and the characteristics of gear fault vibration signals, LWA is introduced into gear fault diagnosis. The concept of the instantaneous energy in time- frequency analysis, based on local wave time-frequency spectrum, was used to measure the energy distribution of the signal in time-frequency domain. Furthermore, when tooth wear occurs in gear, the energy of the gear vibration signal would change correspondingly, whilst local wave time-frequency spectrum can exactly provide the instantaneous energy distribution of the signal with the change of the time and frequency. Thus, the fault information of the gear vibration signal can be extracted effectively from the local wave time-frequency spectrum. The analysis results from the experimental signals show that local wave time-frequency analysis could extract the characteristics information of the gear fault vibration signal effectively.

scholarly journals Analysis of the Accelerometer Input–Output Energy Distribution Based on the Upper Bound of Absolute Dynamic Error

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5816
Author(s):  
Krzysztof Tomczyk ◽  
Marek Sieja
Keyword(s):  
Mathematical Modeling ◽  
Energy Distribution ◽  
Upper Bound ◽  
Dynamic Error ◽  
Output Energy ◽  
Input Output ◽  
Input And Output ◽  
The Absolute

This paper presents an analysis of the accelerometer input–output energy distribution based on the upper bound of the absolute dynamic error (UBADE). This analysis corresponds to the input and output accelerometer signals, determined previously by mathematical modeling. Obtained results may provide the basis for verifying the correctness of the algorithms intended for the determination of the UBADE.

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