Preliminary study on wave field and dispersion characteristics of channel waves in VTI coal seam media

2019 ◽  
Vol 67 (5) ◽  
pp. 1379-1390
Author(s):  
Guangzhong Ji ◽  
Hui Li ◽  
Jiuchuan Wei ◽  
Sitong Yang
Keyword(s):  
Coal Seam ◽  
Wave Field ◽  
Dispersion Characteristics ◽  
Preliminary Study

scholarly journals A preliminary study of oxidant stimulation for enhancing coal seam permeability: Effects of sodium hypochlorite oxidation on subbituminous and bituminous Australian coals

2018 ◽  
Vol 200 ◽  
pp. 36-44 ◽  
Author(s):  
Zhenhua Jing ◽  
Shilo A. Mahoney ◽  
Sandra Rodrigues ◽  
Reydick D. Balucan ◽  
Jim Underschultz ◽  
...  
Keyword(s):  
Coal Seam ◽  
Sodium Hypochlorite ◽  
Preliminary Study

Seismic Record Simulation of the Coalbed in HTI Media

2011 ◽  
Vol 393-395 ◽  
pp. 935-938
Author(s):  
Yi Chen Zhao ◽  
Hui Wang ◽  
Yan Sun
Keyword(s):  
Coal Seam ◽  
Wave Field ◽  
Single Shot ◽  
Fracture Detection ◽  
Seismic Record ◽  
Element Simulation ◽  
Hti Media ◽  
Component Wave ◽  
Anisotropic Elastic ◽  
Hti Medium

This paper uses the finite element simulation system of the anisotropic elastic wave to simulate the two component wave field characteristics of the HTI medium in the coal-seam with fractures. The simulation results of the single shot record indicate that when the coal-seam contains fracture. The wave field characteristics under different fracture parameters are observed through the single shot record. The influences can be found mainly in the energy and amplitude vers offset characteristics. The characteristics of x component and z component are different. This may provide some experimental references to fracture detection using the PS-wave.

scholarly journals Experimental Study on Characteristics of Reactance Dispersion of Water Bearing Coal

2020 ◽  
Author(s):  
Dongji Lei ◽  
Jian Li ◽  
Hui Meng ◽  
Yajuan Wang
Keyword(s):  
Coal Seam ◽  
Frequency Band ◽  
Water Saturation ◽  
Characteristic Curve ◽  
Induced Polarization ◽  
Dispersion Characteristics ◽  
Dielectric Polarization ◽  
Interference Phenomenon ◽  
Complex Resistivity ◽  
Resistivity Method

Abstract As an emerging geophysical exploration method, complex resistivity method is a potential non-invasive one for evaluating hydrofracturing effect. Reactance X is an important parameter of complex resistivity method. Compared with the traditional parameter resistance R, reactance has advantages such as distinct dispersion characteristics, clear conduction mechanism and rich information. In this paper, reactance X of four kinds of coal sample with different water saturation was tested, their dispersion characteristics were analyzed, and their conductive mechanism was studied. The results show that, (1) the characteristic curve of reactance dispersion presents a three-stage law when the water saturation is low, and a two-stage law when the water saturation is high,to some extent, the water content of coal body and the effect of hydraulic fracturing are distinguished;(2) polarization is the cause of dispersion, in which low frequency is induced polarization, high frequency is dielectric polarization, and electromagnetic induction is the interference phenomenon in the frequency band of induced polarization; (3) spectrum extremum frequency point is sensitive to changed water saturation. Extremum points of different coal rank are concentrated in 100-1000Hz. This frequency band can serve as the dominant frequency band for evaluating coal seam water saturation. This paper gives new insight into the evaluation of coal seam hydrofracturing effect by complex resistivity method.

Wave Field Characteristics of Small Faults around the Loose Circle of Rock Surrounding a Coal Roadway

2020 ◽  
Vol 25 (2) ◽  
pp. 245-254 ◽  
Author(s):  
Bo Wang ◽  
Huachao Sun ◽  
Lanying Huang ◽  
Shengdong Liu ◽  
Biao Jin ◽  
...  
Keyword(s):  
Coal Seam ◽  
Wave Field ◽  
Love Wave ◽  
The Body ◽  
Body Waves ◽  
Seismic Record ◽  
Coal Roadway ◽  
Geological Conditions ◽  
Small Fault ◽  
Channel Wave

The geological conditions of coal roadway excavation are complicated. Seismic advanced detection is strongly influenced by the loose circle of fractured rock surrounding the competent coal seam. However, the three-dimensional wave field characteristics of small fault advanced detection in the condition of the loose circle of coal roadway have not examined. In this paper, numerical modeling and field tests were conducted to address this knowledge gap. The results indicate that when a seismic source near the tunnel face is excited, the body waves and a Love channel wave propagate in the tunneling direction toward the small fault, then produces reflected body waves whose amplitude is relatively weak, and a reflected Love channel wave whose amplitude is relatively strong. When reflected body waves and the reflected Love channel wave enter the loose circle of surrounding rock, the former's signal is unrecognizable in seismic record; but the latter converts to a Love wave whose amplitude is strong in the loose circle of coal seam. The Love wave which has a large interval from other wave trains in the time domain is easily recognizable in seismic record, which makes it suitable for advanced detection of small fault. The signal-to-noise ratio of seismic record of X component is higher than those of Y component and Z component.

Monte Carlo Algorithms for Moments of Transition Arrays

1988 ◽  
Vol 102 ◽  
pp. 79-81
Author(s):  
A. Goldberg ◽  
S.D. Bloom
Keyword(s):  
Monte Carlo ◽  
State Vector ◽  
Basis Vector ◽  
Collective State ◽  
Dispersion Characteristics ◽  
Dipole Strength ◽  
The Third ◽  
Monte Carlo Algorithms ◽  
Third Moment ◽  
Very High

AbstractClosed expressions for the first, second, and (in some cases) the third moment of atomic transition arrays now exist. Recently a method has been developed for getting to very high moments (up to the 12th and beyond) in cases where a “collective” state-vector (i.e. a state-vector containing the entire electric dipole strength) can be created from each eigenstate in the parent configuration. Both of these approaches give exact results. Herein we describe astatistical(or Monte Carlo) approach which requires onlyonerepresentative state-vector |RV> for the entire parent manifold to get estimates of transition moments of high order. The representation is achieved through the random amplitudes associated with each basis vector making up |RV>. This also gives rise to the dispersion characterizing the method, which has been applied to a system (in the M shell) with≈250,000 lines where we have calculated up to the 5th moment. It turns out that the dispersion in the moments decreases with the size of the manifold, making its application to very big systems statistically advantageous. A discussion of the method and these dispersion characteristics will be presented.

The Ultrastructure of Metastatic Human Mammary Carcinoma After Prolonged Estrogen Therapy

1967 ◽  
Vol 25 ◽  
pp. 180-181
Author(s):  
John H.L. Watson ◽  
John L. Swedo ◽  
R.W. Talley
Keyword(s):  
Mammary Carcinoma ◽  
Osmium Tetroxide ◽  
Estrogen Therapy ◽  
Ultrastructural Level ◽  
Uranyl Acetate ◽  
Human Mammary Carcinoma ◽  
Surgical Biopsy ◽  
Lead Hydroxide ◽  
Preliminary Study ◽  
Hormonal Therapies

A preliminary study of human mammary carcinoma on the ultrastructural level is reported for a metastatic, subcutaneous nodule, obtained as a surgical biopsy. The patient's tumor had responded favorably to a series of hormonal therapies, including androgens, estrogens, progestins, and corticoids for recurring nodules over eight years. The pertinent nodule was removed from the region of the gluteal maximus, two weeks following stilbestrol therapy. It was about 1.5 cms in diameter, and was located within the dermis. Pieces from it were fixed immediately in cold fixatives: phosphate buffered osmium tetroxide, glutaraldehyde, and paraformaldehyde. Embedment in each case was in Vestopal W. Contrasting was done with combinations of uranyl acetate and lead hydroxide.

Fine structure of early degenerating myofibers in the tibialis anterior of young ‘MDX’ mouse

1988 ◽  
Vol 46 ◽  
pp. 322-323
Author(s):  
H.D. Geissinger ◽  
C.K. McDonald-Taylor
Keyword(s):  
Fine Structure ◽  
Muscle Regeneration ◽  
Tibialis Anterior ◽  
Genetic Defect ◽  
Mdx Mouse ◽  
Mdx Mice ◽  
Histopathological Changes ◽  
Electron Microscopic ◽  
Dystrophic Mouse ◽  
Preliminary Study

A new strain of mice, which had arisen by mutation from a dystrophic mouse colony was designated ‘mdx’, because the genetic defect, which manifests itself in brief periods of muscle destruction followed by episodes of muscle regeneration appears to be X-linked. Further studies of histopathological changes in muscle from ‘mdx’ mice at the light microscopic or electron microscopic levels have been published, but only one preliminary study has been on the tibialis anterior (TA) of ‘mdx’ mice less than four weeks old. Lesions in the ‘mdx’ mice vary between different muscles, and centronucleation of fibers in all muscles studied so far appears to be especially prominent in older mice. Lesions in young ‘mdx’ mice have not been studied extensively, and the results appear to be at variance with one another. The degenerative and regenerative aspects of the lesions in the TA of 23 to 26-day-old ‘mdx’ mice appear to vary quantitatively.

Ultrastructural observations of the aorta of calves implanted with a mechanical left ventricular assist device

1990 ◽  
Vol 48 (3) ◽  
pp. 834-835
Author(s):  
J P Cassella ◽  
V Salih ◽  
T R Graham
Keyword(s):  
Left Ventricular Assist Device ◽  
Ventricular Assist Device ◽  
Left Ventricular ◽  
Aortic Tissue ◽  
Assist Device ◽  
Ventricular Assist ◽  
Transmission Electron ◽  
Left Ventricular Assist ◽  
Preliminary Study

Left ventricular assist systems are being developed for eventual long term or permanent implantation as an alternative to heart transplantation in patients unsuitable for or denied the transplant option. Evaluation of the effects of these devices upon normal physiology is required. A preliminary study was conducted to evaluate the morphology of aortic tissue from calves implanted with a pneumatic Left Ventricular Assist device-LVAD. Two 3 month old heifer calves (calf 1 and calf 2) were electively explanted after 128 days and 47 days respectively. Descending thoracic aortic tissue from both animals was removed immediately post mortem and placed into karnovsky’s fixative. The tissue was subsequently processed for transmission electron microscopy (TEM). Some aortic tissue was fixed in neutral buffered formalin and processed for routine light microscopy.

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