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Список видань за алфавітом назв: Авторський покажчик Покажчик назв публікацій  |
Пошуковий запит: (<.>A=Klymenko D$<.>) | |||
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Загальна кількість знайдених документів : 7 Представлено документи з 1 до 7 |
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| 1. | Klymenko D. W. Próba rekonstrukcji obrazu lwowa w języku literackim Mariana Hemara [Електронний ресурс] / D. W. Klymenko // Наукові праці Кам'янець-Подільського національного університету імені Івана Огієнка. Філологічні науки. - 2013. - Вип. 34. - С. 135-138. - Режим доступу: http://nbuv.gov.ua/UJRN/Npkpnu_fil_2013_34_39 | ||
| 2. | 
Shcherbakov P. Statistical research of shovel excavator performance during loading of rock mass of different crushing quality [Електронний ресурс] / P. Shcherbakov, D. Klymenko, S. Tymchenko // Науковий вісник Національного гірничого університету. - 2017. - № 1. - С. 49-54. - Режим доступу: http://nbuv.gov.ua/UJRN/Nvngu_2017_1_10 Purpose. Applying technical means to control excavator performance and quality of rock crushing by explosion. Establishing the dependence of time consumption required for rock mass excavation on its particle size distribution and mathematical description of this dependence as a function of two variables. Methodology. The methodological basis to solve the problem is a comprehensive approach including research by means of IGS-5M devices, applying mathematical statistics methods and analysing the results in the mathematical package. Findings. The possibility to maintain operational control of the time consumption required for rock mass excavation and direct measurement of its particle size distribution at the same time has been implemented. The concept of cycle rate has been introduced and its dependence on the mean diameter of the piece has been determined. The empirical formula to determine excavator technical performance as a function of two variables that uniquely characterize the quality of rock mass fragmentation has been obtained. Originality. For the first time in the practice of mining the hardware specifically designed for operational control of excavators and crushing of rocks by explosion has been used (IGS-5M devices is in the invention stage). A two-parameter distribution function of the rock mass particle size distribution was proposed where one parameter is the size of the dominant fraction, the other one is the fraction in the test volume of blasted rock. The formula to determine excavator technical performance as a function of specified parameters has been obtained. Practical value. Applying specified devices while organizing and carrying out mining operations will allow using technically feasible solutions at the design stage of mass explosions. Using the formula to calculate excavator technical performance in specific conditions will help improve planning technological processes, especially the rational distribution of freight flows. In the long view, the above mentioned formula will be a critical part of the mathematical model while optimizing basic technological processes at the open pits. | ||
| 3. |
Sdvyzhkova О. Effect of harmonic oscillations on a crack initiation in the rock mass [Електронний ресурс] / О. Sdvyzhkova, Yu. Golovko, D. Klymenko // Науковий вісник Національного гірничого університету. - 2017. - № 4. - С. 13-18. - Режим доступу: http://nbuv.gov.ua/UJRN/Nvngu_2017_4_4 Purpose. The purpose is to improve, develop and generalize the criterion of a crack initiation taking into account the simultaneous effect of the rock stress state and oscillatory processes. The influence of the oscillation amplitude-frequency characteristics on the critical crack length has to be studied as well. Methodology. The methodological basis of the problem solution is a comprehensive approach that includes the mathematical analysis, numerical methods for solving transcendental equations, analysis of the results in the mathematical package Mathcad. Findings. A crack initiation criterion has been developed considering both static stresses (tensile and compressive) and dynamic stress in an elastic wave spreading in the rock mass. The critical length of the initiated crack is determined depending on oscillation amplitude and frequency, static stress and rock crack resistance. The abrupt change in the critical crack length is defined as an indication of the dynamic rock failure. The values of oscillation frequency provoking a decrease in the critical crack length and dynamic rock failure are determined for different rocks. Originality. New approach is used to describe the rock destruction considering the elastic oscillations in the rock mass. The criterion of a crack initiation has been generalized to consider the action of both tensile and compressive stress near by the crack and harmonic stress in an elastic wave. So, based on a common time-space failure criterion, we take into account the stress which is a sum of quasi-stationary and harmonic components. In this paper we focused on the critical crack length that provokes the crack initiation. The influence of oscillation amplitude and frequency on critical length altering has been estimated for different values of the crack resistance. Practical value. The results obtained in the study of criterion crack initiation, can be used to improve the acoustic forecast of gas-dynamic phenomena by the amplitude-frequency characteristics of oscillations. For this purpose, we defined ranges of harmonic oscillation frequencies in some rocks (fine-grained sandstone, limestone, siltstone, coal) in which the initiating of "short" cracks occurs. And we got the real conditions (for coal), in which a slight change in the oscillation amplitude in the array of rocks leads to a jump in the length of the cracks. | ||
| 4. | 
Golovko Y. M. Probability model for the error estimation at seismic-acoustic forecast while coal mining [Електронний ресурс] / Y. M. Golovko, D. V. Klymenko, O. O. Sdvyzhkova // Математичне моделювання. - 2019. - № 2. - С. 71-77. - Режим доступу: http://nbuv.gov.ua/UJRN/Mm_2019_2_11 | ||
| 5. |
Shashenko O. Rigidity effect of the mine geophone mounting on its frequency response [Електронний ресурс] / O. Shashenko, Yu. Golovko, D. Klymenko // Naukovyi visnyk Natsionalnoho Hirnychoho Universytetu. - 2021. - № 3. - С. 44-50. - Режим доступу: http://nbuv.gov.ua/UJRN/Nvngu_2021_3_9 Purpose. To determine the rigidity effect of the changes in mine geophones mounting on the frequency response of the recorded seismoacoustic signals. Methodology. Operational calculus and frequency analysis are used. Findings. The dependences of the frequency characteristics of geophones under coupling conditions with the rock are studied. A possibility is shown of qualitative change in the recorded signal when changing the rigidity of installation of the case of a geophone; moreover, increase in rigidity can result in both increase and decrease in the amplitude of frequency components in a fixed frequency range. The calculations are performed for the parameters characteristic of the current use of geophones and the most common rocks. Electrodynamic velocimeter and piezoelectric accelerometer were considered separately. Originality. Frequency response changes in the seismoacoustic signal recorded by the geophone can be caused by the changes in the rigidity at the coupling between the geophone and the rock. The ratio of the installation frequency to the natural frequency of the geophone can serve as an indicator of the possible rigidity effect. Numerical values of this indicator are proposed. Practical value. Critical analysis of the obtained seismoacoustic data, taking into account the possible changes in the geophone installation rigidity in the measurement time. The need to determine the frequency of the geophone mounting in their initial mounting and periodic control to this parameter for further operation. | ||
| 6. |
Vlasov S. Mathematical model of the process for forming a pure cement zone around the hardened elements using jet technology [Електронний ресурс] / S. Vlasov, S. Tymchenko, D. Klymenko, P. Shcherbakov // Математичне моделювання. - 2023. - № 1. - С. 56-61. - Режим доступу: http://nbuv.gov.ua/UJRN/Mm_2023_1_9 | ||
| 7. |
Aitkazinova Sh. Mathematical modeling the quarry wall stability under conditions of heavily jointed rocks [Електронний ресурс] / Sh. Aitkazinova, O. Sdvyzhkova, N. Imansakipova, D. Babets, D. Klymenko // Naukovyi visnyk Natsionalnoho Hirnychoho Universytetu. - 2022. - № 6. - С. 18-24. - Режим доступу: http://nbuv.gov.ua/UJRN/Nvngu_2022_6_5 Purpose. To develop techniques for estimating the pit wall stability in terms of occurring of a zone of heavily jointed rock mass during ore mining at the Akzhal deposit (Kazakhstan), to work out measures to strengthen the rock opening and to verify the effectiveness of the developed measures. Methodology. The finite element analysis of the rock stress-strain state is implemented on the basis of the elastic-plastic model and the generalized Hoek - Brown failure criterion. The rock mass "quality" was assessed using the RMR and GSI rating classifications. This made it possible to simulate a zone of intense fracturing by changing the characteristics of the jointed surface. The "shear strength reduction" procedure was used to determine the safety factor for the quarry wall. Findings. The strain distributions in the rock mass forming the quarry wall have been obtained in terms of the Akzhal polymetallic ore deposit (Kazakhstan). The case of creating a zone of heavily jointed rocks in the area of a tectonic fault was considered. The safety factor of the quarry wall was determined under conditions of increased rock fracturing, as well as after carrying out measures to strengthen the rocks with a hardening solution. Originality. The effect of intense jointness on the pit wall stability is demonstrated. A method for the consistent evaluation of the quarry wall stability is proposed considering the change in the rock properties due to natural factors and artificial reinforcement. It is shown that a change in the joint surface quality due to the hardening injection reduces the shear strains in the sliding zone. Practical value. The pit wall stability was predicted considering the formation of a zone of intense fracturing under mining and geological conditions of the Akzhal deposit. The possibility of testing the effectiveness of rock strengthening measures based on mathematical modeling was shown. | ||
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