scholarly journals Calculation of permeability coefficient of coal seam under rapid measurement conditions

2019 ◽  
Vol 136 ◽  
pp. 04004
Author(s):  
Manzheng Yang ◽  
Bingrui Li ◽  
Shubo Li
Keyword(s):  
Coal Seam ◽  
Permeability Coefficient ◽  
Integral Transformation ◽  
Gas Permeability ◽  
Rapid Determination ◽  
Flow State ◽  
Time Curve ◽  
Pressure Time ◽  
The Relationship

In order to achieve rapid determination of coal seam permeability, the calculation method of coal seam permeability coefficient was studied. Based on the Darcy's law in the flow of gas in the coal seam, the relationship equation between the gas pressure of the borehole and the gas permeability coefficient of the coal seam is established under the radial unsteady flow state. The gas permeability coefficient of the coal seam is obtained by coordinate transformation and integral transformation. Solve the expression. The analysis and verification of the field measured data show that the expression of the analytical solution of the coal seam permeability coefficient is consistent with the variation of the borehole pressure-time curve, which can provide a theoretical basis for the rapid determination of coal seam permeability.

scholarly journals Permeability of Concrete and Correlation with Microstructure Parameters Determined by 1H NMR

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Yurong Zhang ◽  
Shengxuan Xu ◽  
Zhaofeng Fang ◽  
Junzhi Zhang ◽  
Chaojun Mao
Keyword(s):  
Water Permeability ◽  
Permeability Coefficient ◽  
Pore Diameter ◽  
Gas Permeability ◽  
Steady State Flow ◽  
Test Device ◽  
Water Permeability Coefficient ◽  
Microstructure Parameters ◽  
The Relationship ◽  
Better Than

Water and gas permeability coefficients of concrete with different water-binder (w/b) ratios and admixtures were measured by a self-designed test device based on the steady-state flow method for liquid and the method of differential pressure in stability for gas, respectively. In addition, the micropore structure of concrete was determined by 1H nuclear magnetic resonance (NMR). Results indicated that there are good correlations between water and gas permeability of concrete with different w/b ratios, with correlation coefficient greater than 0.90. Better correlations between water permeability and segmental contributive porosity ranged from 10 to 100 nm and 100 to 1000 nm can be identified, but the gas permeability is more relevant to the segmental contributive porosity ranging from 100 to 1000 nm. Moreover, the correlation between water permeability and contributive porosity for each pore diameter is always better than that of gas permeability. The influence of admixtures on the relationship between permeability and pore size distribution of concrete is significant. Moreover, water permeability coefficient is one or two orders of magnitude lower than the gas permeability coefficient.

scholarly journals Rapid Determination of Aesculin, Aesculetin and Fraxetin inCortex FraxiniExtract Solutions Based on Ultraviolet Spectroscopy

2011 ◽  
Vol 8 (s1) ◽  
pp. S225-S236 ◽  
Author(s):  
Ming Yang ◽  
Jia-Lei Chen ◽  
Xiu-Feng Shi ◽  
Hui-Jue Niu
Keyword(s):  
Root Mean Square Error ◽  
Reference Data ◽  
Rapid Determination ◽  
Ultraviolet Spectroscopy ◽  
Mean Square ◽  
Chemical Parameters ◽  
Ultraviolet Spectra ◽  
Calibration Models ◽  
The Relationship

To evaluate the application of ultraviolet spectroscopy for the rapid determination of aesculin, aesculetin and fraxetin inCortex fraxiniextract solutions, ultraviolet spectra ofCortex fraxiniextract solutions from different batches were collected in the spectral range from 200 nm to 400 nm. The relationship between ultraviolet spectra and chemical parameters displayed some non-linear characteristics. Thus, K-OPLS was proposed to establish the calibration models for the determination ofCortex fraxiniextract solutions between the reference data and ultraviolet spectra. The calibration results were achieved for the determination ofCortex fraxiniextract solutions. The coefficients of determination in calibration (R2) for aesculin, aesculetin and fraxetin were 0.989, 0.957 and 0.939, while in prediction (R2) were 0.982, 0.979 and 0.962, respectively. And the root-mean-square error of prediction (RMSEP) for aesculin, aesculet and fraxetin were 11.99, 3.02 and 1.59 μg/mL. The results demonstrated that ultraviolet spectroscopy could be used for the rapid determination of these three components inCortex fraxiniextract solutions.

A method of rapid determination of gas pressure in a coal seam based on the advantages of gas spherical flow field

2017 ◽  
Vol 45 ◽  
pp. 502-510 ◽  
Author(s):  
Chaojie Wang ◽  
Shengqiang Yang ◽  
Chenglin Jiang ◽  
Dingding Yang ◽  
Chaojie Zhang ◽  
...  
Keyword(s):  
Flow Field ◽  
Coal Seam ◽  
Rapid Determination ◽  
Gas Pressure

Study on Original Coal Seam Permeability Coefficient

2011 ◽  
Vol 361-363 ◽  
pp. 179-182
Author(s):  
Zi Wen Dong ◽  
Qing Jie Qi ◽  
Nan Hu ◽  
Chang Fu Xu ◽  
Hui Niu
Keyword(s):  
Coal Seam ◽  
Water Flow ◽  
Coal Mine ◽  
Permeability Coefficient ◽  
Gas Flow ◽  
Radial Flow ◽  
Gas Permeability ◽  
Coal Seam Gas ◽  
Flow Method

In the case of gas radial flowing in layer-though boring, use the method of draining water gathering gas measured the Gas flow of borehole that there is water flow out from drilling Sometimes,the coal seam gas permeability coefficient is calculated using"Radial Flow Method"and"Optimizing Method,found out the range of 5-3 original coal seam Hongmiao coal mine permeability coefficient is0.007~0.008 m2/(MPa2·d).

scholarly journals Rapid Determination of Nitrogen Status in Pansy

HortScience ◽  
2003 ◽  
Vol 38 (4) ◽  
pp. 537-541 ◽  
Author(s):  
James E. Altland ◽  
Charles H. Gilliam ◽  
Gary J. Keever ◽  
James H. Edwards ◽  
Jeff L. Sibley ◽  
...  
Keyword(s):  
Nitrate Concentration ◽  
Rapid Determination ◽  
Dry Weight ◽  
Foliar Nitrogen ◽  
N Deficiency ◽  
Highly Correlated ◽  
The Relationship ◽  
Spad Readings ◽  
N Status

Two experiments were conducted with pansy (Viola ×wittrockiana Gams `Bingo Yello') to determine the relationship between foliar nitrogen (% of dry weight) (FN) and either sap nitrate concentration (SN) in petioles or SPAD readings of foliage. FN was highly correlated to SN throughout both experiments (r = 0.80 to 0.91). FN was poorly correlated to SPAD readings early in both experiments (r = 0.54 to 0.65), but more highly correlated later when visual symptoms of N deficiency were apparent (r = 0.84 to 0.90). SN determined with the Cardy sap nitrate meter was a reliable predictor of FN in pansy, while SPAD readings were only reliable after symptoms of N deficiency were visually evident. FN can be predicted with SN using the following equation: log(SN) = 0.47*FN + 1.6 [r2 = 0.80, n = 132]. Growers and landscape professionals can use SN readings to predict FN levels in pansy, and thus rapidly and accurately diagnose the N status of their crop.

Study and Application on a New Type of Rapid Determination Model of Gas Content

2014 ◽  
Vol 962-965 ◽  
pp. 1201-1204
Author(s):  
Xiao Hua Jin ◽  
Bei Fang Gu ◽  
San Feng Bai ◽  
Xin Yao Guo ◽  
Ming Gang Luo
Keyword(s):  
Linear Regression ◽  
Coal Seam ◽  
Rapid Determination ◽  
Gas Content ◽  
Characteristic Parameters ◽  
Accuracy Rate ◽  
Theoretical Derivation ◽  
Residual Amount ◽  
New Type

Against the problem of calculating gas content rapidly, this article studied the desorption characteristics of coal by measuring the characteristic parameters of coal in the laboratory. With the actually measured amount of desorption and the desorption rule of the coal within the first 30min, through theoretical derivation and Multiple Linear Regression, the gas content desorbs within the first 120min and the residual amount after a 120min of coal desorption is studied and confirmed Based on the rapid determination model of gas content in the coal seam is established, and the new model is verified, whose accuracy rate reaches above 85%. If relevant electronic equipments were made, this method would be able to give a result within 40min, thereby realizing the rapid determination of gas content in the coal seam within the gas belt.

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