Study on the law of mining-induced fractures field evolution based on similar simulation experiment

For low-permeability coal seam, the gas extraction rate is relatively low. The repeated low-intensity shock wave can improve the permeability of coal and raise the rate of coal seam gas drainage. A simulation test platform was set up to carry out repeated low-intensity shock wave simulation experiment. Under the effect of repeated low-intensity shock wave, the development process of the macrofracture, pore evolution, and the law of microcrack propagation was analyzed to study the law of coal fracture propagation. Research shows that the expansion of the pore of the coal is made by the development of large, medium, and micropores by the repeated low-strength shock wave. The main contribution of the total pore volume increase comes from the micropore growth. The microcrack of the coal mainly begins to sprout and develops from the telocollinite where the fracture is more developed. With the increase of impact times, the microcracks extend to other components. Under the impact of different times, the fractal dimension of the coal sample increases with the increase in the number and length of cracks.

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Experimental Investigating of Latex Cement as Similar Material Simulating Soft Rock Creep

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.535-537.1940 ◽

2012 ◽

Vol 535-537 ◽

pp. 1940-1943

Author(s):

Yong Yan Wang ◽

Feng Li ◽

Xiu Jiang Tai

Keyword(s):

Soft Rock ◽

Fine Sand ◽

Polymer Materials ◽

Similar Material ◽

Ansys Simulation ◽

Rock Creep ◽

Similar Simulation Experiment ◽

Styrene Butadiene ◽

Rock Rheology ◽

Similar Simulation

This paper takes styrene-butadiene latex with 37% solid contents, the portland cement of number 45r and fine sands with 0.2mm diameter to prepared similar material, the mass ratio of cement and fine sand is fixed, different ratio of the specimens are prepared by adjusting the latex ratio. The MATLAB fitting and ANSYS simulation calculation are used to compare to the date of soft rock. The analysis shows that the latex cement can be used for deep soft rock rheology theory and polymer materials similar simulation experiment.

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HREM observation of dislocations near room temperature fractures in silicon

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100106521 ◽

1988 ◽

Vol 46 ◽

pp. 892-893

Author(s):

M. H. Rhee ◽

W. A. Coghlan

Keyword(s):

Cross Section ◽

Room Temperature ◽

Single Crystal Silicon ◽

Dislocation Nucleation ◽

Back Side ◽

Ion Milling ◽

Crystal Silicon ◽

Flat Surfaces ◽

Induced Fractures ◽

Vicker’S Microhardness

Silicon is believed to be an almost perfectly brittle material with cleavage occurring on {111} planes. In such a material at room temperature cleavage is expected to occur prior to any dislocation nucleation. This behavior suggests that cleavage fracture may be used to produce usable flat surfaces. Attempts to show this have failed. Such fractures produced in semiconductor silicon tend to occur on planes of variable orientation resulting in surfaces with a poor surface finish. In order to learn more about the mechanisms involved in fracture of silicon we began a HREM study of hardness indent induced fractures in thin samples of oxidized silicon.Samples of single crystal silicon were oxidized in air for 100 hours at 1000°C. Two pieces of this material were glued together and 500 μm thick cross-section samples were cut from the combined piece. The cross-section samples were indented using a Vicker's microhardness tester to produce cracks. The cracks in the samples were preserved by thinning from the back side using a combination of mechanical grinding and ion milling.

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Ethical Challenges: Less About Moral Wrongdoing and More About Communication Breakdown

Perspectives on Gerontology ◽

10.1044/gero20.3.72 ◽

2015 ◽

Vol 20 (3) ◽

pp. 72-84 ◽

Cited By ~ 2

Author(s):

Paula Leslie ◽

Mary Casper

Keyword(s):

Ethical Challenges ◽

Speech Language Pathology ◽

Thickened Liquids ◽

Communication Breakdown ◽

Professional Duty ◽

Language Pathology ◽

The Law ◽

Personal Case

“My patient refuses thickened liquids, should I discharge them from my caseload?” A version of this question appears at least weekly on the American Speech-Language-Hearing Association's Community pages. People talk of respecting the patient's right to be non-compliant with speech-language pathology recommendations. We challenge use of the word “respect” and calling a patient “non-compliant” in the same sentence: does use of the latter term preclude the former? In this article we will share our reflections on why we are interested in these so called “ethical challenges” from a personal case level to what our professional duty requires of us. Our proposal is that the problems that we encounter are less to do with ethical or moral puzzles and usually due to inadequate communication. We will outline resources that clinicians may use to support their work from what seems to be a straightforward case to those that are mired in complexity. And we will tackle fears and facts regarding litigation and the law.

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