scholarly journals INFLUENCE OF TECTONIC DISTURBANCES OF COAL LAYER ON HIS GAS DYNAMIC STATE

2021 ◽  
Vol 26 (1(38)) ◽  
pp. 192-204
Author(s):  
V. V. Zberovskyi ◽  
P. S. Pashenko ◽  
A. V. Pazynich ◽  
S. V. Stefanko
Keyword(s):  
Coal Seam ◽  
Strength Properties ◽  
Dynamic State ◽  
Gas Dynamic ◽  
Disturbed Zone ◽  
Tectonic Disturbances ◽  
Sudden Release ◽  
High Degree ◽  
Outburst Hazard

Problem Statement and Purpose. At one of the coal mines of the Donetsk basin, there was a sudden release of coal and gas. The peculiarity of this case is that the accident happened in the place of the alleged development of a geological disturbance, but without any visible signs of this. Inspection of the ejection site and adjacent horizons made it possible to conclude that the emergency site is located in the place of the plicative disturbance development. Thus, it is necessary to study in more detail the influence of disturbed zones hidden nature on the gas-dynamic state of the reservoir, as well as to develop and implement methods for determining such zones. Data & Methods. To achieve this goal, a new method was tested, based on the property of structureless substances to form crystal-like units. This phenomenon has been studied for decades; therefore, such new formations have long been given the name quasicrystals. It was noted that the increase in the concentration of such forms is associated with the presence of geological disturbances. Consequently, the increase in quasicrystals in the rock is an indicator of its disturbance due to the influence of tectonic pressure. Thus, in order to test the technique and reveal the hidden geological disturbance of the coal seam, coal samples were taken, microstructural features were studied, and the strength of the coal seam was measured at 56 points. Result. As a result the values of the concentration of quasicrystals, data on the strength of the formation were obtained, a schematic map of the development of the disturbance in this area was built, its contours were determined, the center of the disturbed zone was identified and the role of such disturbances in the outburst hazard of the formation was substantiated. It has been established that geological disturbances, even of plicative nature, have a high degree of fracturing. Such pores and cracks in coal reduce the strength properties and are able to concentrate sufficient volumes of gas for manifestation of GDP.

scholarly journals The results of monitoring of hydroimpulsive disintegration of outburst-prone coal seams using ZUA-98 system

2020 ◽  
Vol 168 ◽  
pp. 00068
Author(s):  
Vasyl Zberovskyi ◽  
Kostiantyn Sofiiskyi ◽  
Rishard Stasevych ◽  
Artem Pazynych ◽  
Jan Pinka ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Rock Mass ◽  
Coal Seam ◽  
High Frequency ◽  
Strain State ◽  
Monitoring And Evaluation ◽  
Dynamic State ◽  
Coal Seams ◽  
Gas Dynamic ◽  
Mine Workings

The paper represents the results of monitoring and evaluation of the efficiency of hydroimpulsive disintegration of outburst-prone coal seams in the stopes of development mine workings using a system of sound detecting facilities. Methods of acoustic emission control have been considered as well as the monitoring tasks to evaluate rock mass conditions before the procedure and after it inclusive of the results of sound accompaniment of hydraulic disintegration of the coal seam. It has been determined that the higher concentration of stresses within the rock mass is, the more efficient action of high frequency self-oscillations of cavitation transmitter is on both the fissuring and changes in gas-dynamic state of the coal seam. It has been recommended to apply a mode of impulsive fluid pumping under the conditions where coal seam is in the stress-strain state.

Investigation into the Gas-Dynamic State of a Coal Seam under Degassing and Moistening

2005 ◽  
Vol 41 (2) ◽  
pp. 168-176
Author(s):  
A. D. Ruban ◽  
G. S. Zaburdyaev ◽  
V. S. Zaburdyaev
Keyword(s):  
Coal Seam ◽  
Dynamic State ◽  
Gas Dynamic

Labor safety and control of the working area state in the penals while mining steep coal seams by shield aggregates

2020 ◽  
pp. 47-64
Author(s):  
V.V. Zberovskyi ◽  
◽  
R.А. Ahaiev ◽  
K.K. Sofiiskyi ◽  
B.М. Dehlin ◽  
...  
Keyword(s):  
Coal Seam ◽  
Physical And Mechanical Properties ◽  
Dynamic State ◽  
Coal Seams ◽  
Gas Dynamic ◽  
Geological Conditions ◽  
Labor Safety ◽  
Sudden Outburst ◽  
District Change ◽  
And Control

In this article, circumstances and factors which can lead to a degraded labour protection and occurrence of emergency in a district are reviewed and analyzed on the example of an accident occurred at sudden coal-and-gas outburst in the panel face № 42-1146 m of the Tovstyi-Zakhid seam m3 in the Central Mine of the Toretsvukhillia Mining Company. In this article, state of equipment and its location in the district in accordance with the requirements of the safety rules, records of devices which monitor gas-dynamic state of the coal seam and operation of the shield aggregate are considered. Mining and geological conditions of the seam bedding and technological conditions of the district location within the working horizon; methane content in the air of the roadways in the district; change of coal physical and mechanical properties in the area of possible geological disturbance; results of control of the coal seam gas-dynamic state analyzed by acoustic emission parameters; and other risk factors that led to emergencies were studied. The decisions made for controlling possible area with geological disturbance impact which was detected in the horizons of 916 m and 1026 m on the basis of mining-graphic materials and data of geological study in the mining roadways adjacent to the panel No. 14 in the district 42-1146 m were analyzed. The order and sequence of the works established for eliminating consequences of the coal and gas sudden outburst and detecting zone with disturbed coal and outburst cavity were considered. On the basis of the results obtained, conclusions were made and actions were elaborated on preventing accidents at mining steep prone-to-outburst coal seams by the shield aggregates. It is recommended to continue the scientific research for the purpose of detecting zone with possible impact of discontinuous geological disturbance and plicate disturbed zones in the coal seams by the changed hardness of coal in the adjacent panel, and developing certain local measures on preventing gas-dynamic phenomena at mining steep prone-to-outburst seams by the shield aggregates. The objective of this work was to analyze state of the working area and labor protection and to study the conditions and factors which had led to the accident with serious consequences and emergency condition of the panel.

SEM Study of Tension Wood Fiber Morphology and its Effect on Paper Properties

1977 ◽  
Vol 35 ◽  
pp. 308-309
Author(s):  
K. W. Robinson
Keyword(s):  
Tension Wood ◽  
Wood Fiber ◽  
Strength Properties ◽  
Fiber Morphology ◽  
Paper Properties ◽  
Pure Cellulose ◽  
Short Rotation ◽  
Hardwood Trees ◽  
Sem Study

Tension wood (TW) is an abnormal tissue of hardwood trees; although it has been isolated from most parts of the tree, it is frequently found on the upper side of branches and leaning stems. TW has been classically associated with geotropic alignment, but more recently it has been associated with fast growth. Paper made from TW is generally lower in strength properties. Consequently, the paper industries' growing dependence on fast growing, short- rotation trees will result in higher amounts of TW in the final product and a corresponding reduction in strength.Relatively few studies have dealt with the role of TW in the structure of paper. It was suggested that the lower strength properties of TW were due to a combination of factors, namely, its unique morphology, compression failures in the cell wall, and lower hemicellulose content. Central to the unique morphology of the TW fiber is the thick gelatinous layer (G-layer) composed almost entirely of pure cellulose.

scholarly journals Roles of ncRNAs as ceRNAs in Gastric Cancer

Genes ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 1036
Author(s):  
Junhong Ye ◽  
Jifu Li ◽  
Ping Zhao
Keyword(s):  
Gastric Cancer ◽  
Research Strategy ◽  
Circular Rnas ◽  
Messenger Rnas ◽  
Cerna Network ◽  
Degree Of Malignancy ◽  
High Degree ◽  
Competitive Endogenous Rna ◽  
Made In

Although ignored in the past, with the recent deepening of research, significant progress has been made in the field of non-coding RNAs (ncRNAs). Accumulating evidence has revealed that microRNA (miRNA) response elements regulate RNA. Long ncRNAs, circular RNAs, pseudogenes, miRNAs, and messenger RNAs (mRNAs) form a competitive endogenous RNA (ceRNA) network that plays an essential role in cancer and cardiovascular, neurodegenerative, and autoimmune diseases. Gastric cancer (GC) is one of the most common cancers, with a high degree of malignancy. Considerable progress has been made in understanding the molecular mechanism and treatment of GC, but GC’s mortality rate is still high. Studies have shown a complex ceRNA crosstalk mechanism in GC. lncRNAs, circRNAs, and pseudogenes can interact with miRNAs to affect mRNA transcription. The study of the involvement of ceRNA in GC could improve our understanding of GC and lead to the identification of potential effective therapeutic targets. The research strategy for ceRNA is mainly to screen the different miRNAs, lncRNAs, circRNAs, pseudogenes, and mRNAs in each sample through microarray or sequencing technology, predict the ceRNA regulatory network, and, finally, conduct functional research on ceRNA. In this review, we briefly discuss the proposal and development of the ceRNA hypothesis and the biological function and principle of ceRNAs in GC, and briefly introduce the role of ncRNAs in the GC’s ceRNA network.

Surgeon-performed Ultrasound for Primary Hyperparathyroidism

2013 ◽  
Vol 79 (7) ◽  
pp. 681-685 ◽  
Author(s):  
Worthington G. Schenk ◽  
John B. Hanks ◽  
Philip W. Smith
Keyword(s):  
Primary Hyperparathyroidism ◽  
Class 1 ◽  
Additional Imaging ◽  
Surgical Cure ◽  
Operative Findings ◽  
Enhanced Computed Tomography ◽  
High Degree ◽  
Tomography Scan ◽  
Parathyroid Imaging

The role of preoperative parathyroid imaging continues to evolve. This study evaluated whether surgeon-performed ultrasound (U/S) obviates the need for other imaging studies and leads to a focused exploration with a high degree of surgical success. From July 2010 to February 2012, 200 patients presenting with nonfamilial primary hyperparathyroidism underwent neck U/S in the surgeon's office. The U/S interpretation was classified as Class 1 if an adenoma was identified with high confidence, Class 2 if a possible but not definite enlarged gland was imaged, and Class 0 (zero) if no adenoma was identified. The findings were correlated with subsequent intra-operative findings. There were 144 Class 1 U/Ss (72%); of 132 patients coming to surgery, 96.2 per cent had surgical findings concordant with preoperative U/S and all had apparent surgical cure. Twenty-nine patients (14.5%) had Class 2 U/S; the 31 per cent confirmed false-positives in this group were usually colloid nodules. Fourteen of 27 with Class 0 U/S underwent surgery after being offered dynamically enhanced computed tomography scan. All 200 patients were apparent surgical cures. Surgeon-performed U/S is expedient, convenient, inexpensive, and accurate. A clearly identified adenoma can safely lead to a focused limited exploration and avoid additional imaging 93 per cent of the time.

The academic profession in Russia’s two capitals: The impact of 20 years of transition

2017 ◽  
Vol 16 (5) ◽  
pp. 626-644 ◽  
Author(s):  
Elizaveta Sivak ◽  
Maria Yudkevich
Keyword(s):  
Large Scale ◽  
Academic Career ◽  
Academic Profession ◽  
University Faculty ◽  
Key Characteristics ◽  
Personal Strain ◽  
High Degree ◽  
The Impact ◽  
Russian Universities

This paper studies the dynamics of key characteristics of the academic profession in Russia based on the analysis of university faculty in the two largest cities in Russia – Moscow and St Petersburg. We use data on Russian university faculty from two large-scale comparative studies of the academic profession (‘The Carnegie Study’ carried out in 1992 in 14 countries, including Russia, and ‘The Changing Academic Profession Study’, 2007–2012, with 19 participating countries and which Russia joined in 2012) to look at how faculty’s characteristics and attitudes toward different aspects of their academic life changed over 20 years (1992–2011) such as faculty’s views on reasons to leave or to stay at a university, on university’s management and the role of faculty in decision making. Using the example of universities in the two largest Russian cities, we demonstrate that the high degree of overall centralization of governance in Russian universities barely changed in 20 years. Our paper provides comparisons of teaching/research preferences and views on statements concerning personal strain associated with work, academic career perspectives, etc., not only in Russian universities between the years 1992 and 2012, but also in Russia and other ‘Changing Academic Profession’ countries.

Myocardial CO2 buffering: role of transmembrane transport of H+ or HCO3-ions

1976 ◽  
Vol 230 (4) ◽  
pp. 1037-1041 ◽  
Author(s):  
DR Strome ◽  
RL Clancy ◽  
NC Gonzalez
Keyword(s):  
Small Volume ◽  
Coronary Circulation ◽  
Myocardial Cell ◽  
Ringer Solution ◽  
Red Cells ◽  
Transmembrane Transport ◽  
High Degree

Isolated rabbit hearts were perfused with rabbit red cells suspended in Ringer solution. A small volume of perfusate was recirculated for 10 min at Pco2 of 33.4 +/- 0.9 or 150.8 +/- 7.5 mmHg. Hypercapnia resulted in an increase in perfusate HCO3- concentration that was smaller than that observed when isolated perfusate was equilibrated in vitro with the same CO2 tensions (delta HCO-3e = 1.6 mM, P less than 0.01). This difference is consistent with a net movement of HCO3- into or H+ out of the mycardial cell, and cannot be accounted for by dilution of HCO3- in the myocardial interstitium. Recirculation of perfusate through the coronary circulation at normal Pco2 for two consecutive 10-min periods was not followed by changes in perfusate HCO3- concentration. A high degree of correlation (r = 0.81) was observed between intracellular HCO-3e concentration and the corresponding delta HCO-3e in individual experiments. The results suggest that transmembrane exchange of H+ or HCO3- is a buffer mechanism for CO2 in the myocardial cell.

scholarly journals Classification of coal seam outburst hazards and evaluation of the importance of influencing factors

2017 ◽  
Vol 9 (1) ◽  
Author(s):  
Xianzhi Shi ◽  
Dazhao Song ◽  
Ziwei Qian
Keyword(s):  
Coal Seam ◽  
Multivariate Regression ◽  
Multivariate Regression Analysis ◽  
Scientific Basis ◽  
Prevention Measures ◽  
Coal Seam Gas ◽  
Geological Factors ◽  
Hazard Level ◽  
Outburst Hazard

AbstractCoal and gas outbursts are the result of several geological factors related to coal seam gas (coal seam gas pressureTo classify the outburst hazard level of a coal seam by means of statistical methods, this study considered the geological parameters of coal seam gas and statistical data on the amount of material involved in coal outbursts. Through multivariate regression analysis, a multivariate regression equation between the outburst coal quantity andUsing a significance evaluation of the aforementioned factors, the relative contributions of the gas-related geological parameters to the outburst hazard level of a coal seam were found to follow the orderThis work provides a scientific basis for evaluating the outburst hazard level of a coal seam and adopting feasible and economical outburst-prevention measures.

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