scholarly journals Granulometric composition research of mine rocks as a material for backfilling the mined-out area in coal mines

2021 ◽  
Vol 15 (4) ◽  
pp. 122-129
Author(s):  
Mykhailo Petlovanyi ◽  
Dmytro Malashkevych ◽  
Kateryna Sai ◽  
Ievgeniia Bulat ◽  
Vasyl Popovych
Keyword(s):  
Granulometric Composition ◽  
Digital Processing ◽  
Laboratory Research ◽  
Sieve Analysis ◽  
Backfill Material ◽  
The Face ◽  
Analysis Laboratory ◽  
Laboratory Balance ◽  
Granulometric Characteristics

Purpose. Determination of the granulometric characteristics and loosening coefficient of mine rocks formed during stope operations from undercutting the bottom rocks as a potential backfill material based on a set of mine and laboratory research. Methods. To do research, a complex methodology is used, which includes a photographic surveying the mass of destroyed rocks from undercutting the bottom rocks in mine conditions, digital processing and determining the granulometric composition in the software package, sampling the mine rocks at the surface complex, and reconstructing the granulometric composition, similar to the full-scale mine conditions in the laboratory. Sieve analysis, laboratory balance and laboratory container are used to determine the granulometric composition and loosening coefficient. Findings. The dependence between the granulometric composition and loosening coefficient of rocks, which increases by 33% within fractions of 0-50 mm and by 8% within fractions of 50-140 mm, has been revealed. It has been determined that the destroyed rocks in the face within fractions of 0-140 mm have a bulk density of 1.28 g/cm3, loosening coefficient of 1.7, the voidness of and the maximum reserve for the backfill mass compaction with mine rocks is 41.9%. An analytical assessment of the volumes of the formed cavities of the mined-out area in the longwall face and gobed mine workings, as well as the prospects and completeness of their filling with mine rocks have been performed. Originality. It has been determined that the loosening coefficient of mine rocks destroyed in the stope face by KA-200 shearer changes according to the logarithmic dependence on their granulometric composition. This makes it possible to control the granulometric characteristics of the backfill material to achieve the maximum density of the backfill mass. Practical implications. Further research can serve as a basis for determining the rational parameters for the formation and placement of backfill masses during complex-mechanized selective mining of coal seams using various methods of backfilling operations.

SEM/EDS Characterization of Uncommon Metal Whiskers and Determination of Underlying Growth Mechanisms

2018 ◽  
Author(s):  
D. Basak ◽  
L. H. Ponce
Keyword(s):  
Reliability Analysis ◽  
Case Studies ◽  
Whisker Growth ◽  
Innovation Systems ◽  
Growth Mechanisms ◽  
Crystal Oscillator ◽  
Analysis Laboratory ◽  
Investigative Techniques

Abstract Two case-studies on uncommon metals whiskers, performed at the Reliability Analysis Laboratory (RAL) of Northrop Grumman Innovation Systems, are presented. The components analyzed are an Oven Controlled Crystal Oscillator (OCXO) and an Electromechanical Relay. Investigative techniques were used to determine the chemical and physical makeup of the metal whiskers and develop an understanding of the underlying effects and mechanisms that caused the conditions conducive to whisker growth.

scholarly journals Determination of the Vertical Dimension and the Position of the Occlusal Plane in a Removable Prosthesis Using Cephalometric Analysis and Golden Proportion

2021 ◽  
Vol 11 (15) ◽  
pp. 6948
Author(s):  
Gabriele Cervino ◽  
Sergio Sambataro ◽  
Chiara Stumpo ◽  
Salvatore Bocchieri ◽  
Fausto Murabito ◽  
...  
Keyword(s):  
Vertical Dimension ◽  
Occlusal Plane ◽  
X Rays ◽  
Common Procedure ◽  
Lower Incisor ◽  
Golden Proportion ◽  
The Face ◽  
Removable Prosthesis ◽  
Edentulous Patients

The aim of this study is to demonstrate the use and the effectiveness of cephalometry and golden proportions analysis of the face in planning prosthetic treatments in totally edentulous patients. In order to apply this method, latero-lateral and posterior-anterior X-rays must be performed in addition to the common procedure. Two main concerns for totally edentulous patients are the establishment of the vertical dimension and the new position of the occlusal plane. The divine proportion analysis was carried out by the use of a golden divider. The prosthetic protocol was divided into three steps and a case was selected for better understanding. Referring to the golden relations, if the distance from the chin to the wing of the nose is 1.0, the distance from the nose to eye is 0.618. This proportion is useful and effective in determining the correct prosthetic vertical dimension. The incisal margin of the lower incisor must be positioned between Point A (A) and protuberance menti (Pm) according to the gold ratio 0.618 of the total height A-Pm. Posteriorly the occlusal plane must be placed 2 mm below the divine occlusal plane (traced from the incisal margin of lower incisors to Xi point). A prosthesis made in accordance with cephalometric parameters and divine proportions of the face helps to improve the patient’s aesthetics, function and social personality.

scholarly journals Evaluation of Marblewood Dust’s (Marmaroxylon racemosum) Effect on Ignition Risk

2021 ◽  
Vol 11 (15) ◽  
pp. 6874
Author(s):  
Miroslava Vandličkova ◽  
Iveta Markova ◽  
Katarina Holla ◽  
Stanislava Gašpercová
Keyword(s):  
Particle Size ◽  
Dust Particles ◽  
Wood Dust ◽  
Sieve Analysis ◽  
Granulometric Analysis ◽  
Analysis Measurement ◽  
Risk Research ◽  
Minimum Ignition Temperature ◽  
The Impact

The paper deals with the selected characteristics, such as moisture, average bulk density, and fraction size, of tropical marblewood dust (Marmaroxylon racemosum) that influence its ignition risk. Research was focused on sieve analysis, granulometric analysis, measurement of moisture level in the dust, and determination of the minimum ignition temperatures of airborne tropical dust and dust layers. Samples were prepared using a Makita 9556CR 1400W grinder and K36 sandpaper for the purpose of selecting the percentages of the various fractions (<63, 63, 71, 100, 200, 315, 500 μm). The samples were sized on an automatic vibratory sieve machine Retsch AS 200. More than 65% of the particles were determined to be under 100 μm. The focus was on microfractions of tropical wood dust (particles with a diameter of ≤100 µm) and on the impact assessment of particle size (particle size <100 µm) on the minimum ignition temperatures of airborne tropical dust and dust layers. The minimum ignition temperature of airborne marblewood dust decreased with the particle size to the level of 400 °C (particle size 63 μm).

scholarly journals Kemampuan Lulusan Sekolah Tinggi Pariwisata Ampta Dalam Menghadapi Persaingan Di Dunia Kerja

Media Wisata ◽  
2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Sri Larasati
Keyword(s):  
Communication Skill ◽  
Total Population ◽  
Sampling Technique ◽  
Regression Equations ◽  
Test Results ◽  
A Value ◽  
The Face ◽  
Job Competition ◽  
Sampling Approach

The purpose of this research is to know wtether knowledge, skill, responsiveness and communication skill influence in job competition for graduate student from Sekolah Tinggi Pariwisata AMPTA. The population in this study are student pf Sekolah Tinggi Pariwisata SMPTA that graduated in 2013 until 2016, the total population in this studt is 702 and 200 respondents who have worked taken as samples, samples were taken with non probability sampling technique and accidental sampling approach. Sampling approach using regression equations obtained results that through test results F (regression analysis jointly) may note that the value of F = 147.104 count with the significance of 0.000 < 0.05. The test results of the test F reinforced with testing the determination of the coefficient that shows the value of 74.6%) (0.746. From Test t (partially) can result in variable knowledge with a value of t = 3,173 and significance of the value 0002 < 0.05, variable skill with a value of t = 2,949 and value the significance of 0.004 < 0.05, variable attitude with a value of t = 2,688 and value the significance of 0.008 < 0.05, variable communication skill with a value of t = value and significance of 4,497 0000 < 0.05. From the above results can be known that the hypothesis posed was not proven in other words that all of these variables can be said to have a positive and significant effect simultaneously as well as partial toward the ability of STP graduates AMPTA in the face of competition in the world of work

scholarly journals INVESTIGATION OF THE GEOMECHANICAL STATE OF SOFT ADJOINING ROCKS UNDER PROTECTIVE CONSTRUCTIONS

2021 ◽  
Vol 36 (4) ◽  
pp. 61-71
Author(s):  
Serhii Nehrii ◽  
Tetiana Nehrii ◽  
Oksana Zolotarova ◽  
Serhii Volkov
Keyword(s):  
Physical And Mechanical Properties ◽  
New Approach ◽  
Soft Rocks ◽  
The Face ◽  
Geomechanical State ◽  
Rock Mass Failure ◽  
The Stability ◽  
Seam Mining ◽  
Mine Roadways

The conditions of coal seam mining in the mines of Ukraine have been considered. The problem of conducting coal mining by longwalls in the conditions of soft adjoining rocks, which concerns the protection of mine roadways located near the face, has been revealed. In such conditions, the existing protective constructions are ineffective due to the fact that they yield and get pressed into the soft rocks of the footwall. This indicated the need for research into the geomechanical state of soft rocks of the footwall. According to the results of known studies on the mechanism of rock mass failure around roadways and the data of physical and mechanical properties of the coal mass, which is represented by soft rocks, the correlation dependence has been obtained, the use of which allowed for the determination of the parameters of the rock deformation diagram and the establishment of the stability criterion of footwall rocks under the protection means and stability conditions of the geotechnical system “protective construction – adjoining rocks.” They are the basis of a new approach to ensure the stability of the roadways, which are supported behind the faces, by controlling the stress state in the system “protective construction – adjoining rocks.” This may be the basis for the development of new methods of protecting roadways in conditions of soft adjoining rocks.

scholarly journals Development of a mathematical model for calculating the process of crushing hard rocks by explosions of cylindrical charges of explosives

2020 ◽  
Vol 5 ◽  
pp. 30-32
Author(s):  
Norov Yunus Dzhumaevich ◽  
Mehmonov Maksud Rabbonokul ugli
Keyword(s):  
Mathematical Model ◽  
Rock Mass ◽  
Mechanism Of Action ◽  
Mathematical Description ◽  
Granulometric Composition ◽  
Rock Fragmentation ◽  
Hard Rocks ◽  
Definition Of ◽  
The Relationship

The article presents a developed mathematical model for calculating the granulometric composition of the blasted rock mass based on the mechanism of action of an explosion in rocks, a mathematical description of the determination of natural units (blocks) in the rock mass, the relationship between the degree of rock fragmentation and the size of the units and the definition of sections of the controlled pressure zone.

scholarly journals Agroecological assessment of water-physical properties of irrigated soils of the Trans-Urals in the analysis of the main hydrophysical characteristics

2021 ◽  
Vol 36 ◽  
pp. 03014
Author(s):  
I.V. Komissarova ◽  
A.V. Chelovechkova ◽  
N.V. Miroshnichenko
Keyword(s):  
Physical Properties ◽  
Soil Properties ◽  
Granulometric Composition ◽  
Water Transfer ◽  
Soil Stratum ◽  
Irrigation Rate ◽  
Irrigated Soils

Water-physical properties of soils are a set of soil properties that determine the accumulation, preservation and water transfer in the soil stratum. One of the important indicators of water-physical properties are soil-hydrological constants. These indicators can be used in forecasting yield, calculating the irrigation rate. The determination of soil-hydrological constants is a rather laborious process. In this article, we propose to obtain soil-hydrological constants from the data of the main hydrophysical characteristics. This technique allows to analyze the data and obtain soil-hydrological constants from the data of granulometric composition. The conducted studies have shown that the use of uncontrolled irrigation has led to the transformation of water-physical properties, the content of easily mobile, productive and gravitational moisture has decreased. When modeling the MHC curve, a change in the shape on the graphs can be noted.

scholarly journals Digital processing of leaf area of soybeans, subjected to different treatments of seeds

2020 ◽  
Vol 13 (3) ◽  
pp. 24
Author(s):  
M. L. V. Passos ◽  
J. B. C. Souza ◽  
E. A. Silva ◽  
C. A. A. C. Silva ◽  
W. S. Sousa ◽  
...  
Keyword(s):  
Image Processing ◽  
Computer Program ◽  
Leaf Area ◽  
Seed Treatment ◽  
Digital Camera ◽  
Digital Processing ◽  
Thiophanate Methyl ◽  
Beneficial Effects ◽  
Non Destructive

Digital image processing, when applied to the study of leaf area, allows the integration of the direct measurement and non-destructive, and thus preserves the integrity of the plant. The objective was the quantification of the leaf area of soybean, cv. FTS Paragominas RR, submitted to different treatments of seed with the use of the computer program ImageJ, and basic presuppositions of image processing. The experiment was conducted at the Center of Agrarian Sciences and Environmental, Federal University of Maranhão, in Chapadinha (MA), in the period from February to June 2018. The seeds of soybean 'Paragominas RR' were submitted to the technique of seed treatment, consisting of three fungicides of the active ingredients, thiophanate methyl + fluazinam, fludioxonil and carbendazim + tiram, an insecticide active ingredient fipronil and the control. The leaf area was analyzed in the growth phase, through the use of digital camera and ImageJ®. The use of the routines in the computer program ImageJ® were effective for the determination of leaf area of the soybean submitted to different treatments of the seed. The thiophanate methyl + fluazinam in the dose 200 mL per 100 kg of seeds showed beneficial effects on growth of the cv. FTS Paragominas RR, as estimated by the leaf area.

scholarly journals Effect of variable content of organic matter and carbonates on results of determination of granulometric composition by means of Casagrande’s areometric method in modification by Prószyński

2018 ◽  
Vol 69 (1) ◽  
pp. 39-48 ◽  
Author(s):  
Hubert Warzyński ◽  
Agnieszka Sosnowska ◽  
Andrzej Harasimiuk
Keyword(s):  
Organic Matter ◽  
Calcium Carbonate ◽  
Granulometric Composition ◽  
Considerable Effect ◽  
Study Results ◽  
Variable Content ◽  
Practical Conclusion

Abstract The paper discusses the issue of the admixtures’ effect on results of granulometric composition determinations by Casagrande’s areometric method in modification by Prószyński. An experiment was conducted involving preparation of samples with known granulometric composition and determination of their composition by means of the aerometric method. Three types of samples were prepared: base (control), containing organic matter, and containing carbonates. Results of the determinations showed a considerable effect of the admixture of organic matter and calcium carbonate on the accordance of determinations, depending on their percent content. The study results also confirmed known dependencies of disturbances in proportions between the sandy and silty-clayey fraction. A practical conclusion from the research is the determination of the threshold of the organic matter and carbonates percent content at which the determination should be absolutely preceded by processes of mineralisation and decalcification.

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