scholarly journals Assessment of the geomechanical state of the rock mass in the Streltsovsk ore field region according to high-precision deformation measurements

2019 ◽  
Vol 129 ◽  
pp. 01013
Author(s):  
Vladimir Lugovoi ◽  
Igor Rasskazov ◽  
Denis Tsoi ◽  
Andrey Gladyr ◽  
Maksim Rasskazov
Keyword(s):  
Rock Burst ◽  
Experimental Studies ◽  
Low Frequency ◽  
Frequency Measurement ◽  
The State ◽  
External Factors ◽  
Laser Strainmeter ◽  
Geodynamic Monitoring ◽  
Geomechanical State ◽  
Deformation Measurements

The paper presents a measuring set – a single-component laser strainmeter – for geodynamic monitoring within the Streltsovsk ore field. The results of experimental studies with the participation of a laser strainmeter (deformograph) are presented and the influence of external factors on the state of the massif has been estimated. The influence of distant earthquakes on the state of the mountain massif has been estimated. The features of the deformation field behavior during preparation and implementation of a rock burst have been noted. Characteristics of rock burst precursors in the low-frequency measurement region have been given.

Calculation-and-experimental estimation of the role of the frequency ratio in changing the endurance at two-frequency deformation modes

2019 ◽  
Vol 85 (1(I)) ◽  
pp. 64-71 ◽  
Author(s):  
M. M. Gadenin
Keyword(s):  
High Frequency ◽  
Experimental Studies ◽  
Low Frequency ◽  
Reduction Factor ◽  
Single Frequency ◽  
Cyclic Loads ◽  
Small Ratio ◽  
Harmonic Components ◽  
Deformation Modes

The cycle configuration at two-frequency loading regimes depends on the number of parameters including the absolute values of the frequencies and amplitudes of the low-frequency and high-frequency loads added during this mode, the ratio of their frequencies and amplitudes, as well as the phase shift between these harmonic components, the latter having a significant effect only with a small ratio of frequencies. Presence of such two-frequency regimes or service loading conditions for parts of machines and structures schematized by them can significantly reduce their endurance. Using the results of experimental studies of changes in the endurance of a two-frequency loading of specimens of cyclically stable, cyclically softened and cyclically hardened steels under rigid conditions we have shown that decrease in the endurance under the aforementioned conditions depends on the ratio of frequencies and amplitudes of operation low-frequency low-cycle and high-frequency vibration stresses, and, moreover, the higher the level of the ratios of amplitudes and frequencies of those stacked harmonic processes of loading the greater the effect. It is shown that estimation of such a decrease in the endurance compared to a single frequency loading equal in the total stress (strains) amplitudes can be carried out using an exponential expression coupling those endurances through a parameter (reduction factor) containing the ratio of frequencies and amplitudes of operation cyclic loads and characteristic of the material. The reduction is illustrated by a set of calculation-experimental curves on the corresponding diagrams for each of the considered types of materials and compared with the experimental data.

scholarly journals A phase-locked loop using ESO-based loop filter for grid-connected converter: performance analysis

2021 ◽  
Author(s):  
Baoling Guo ◽  
Seddik Bacha ◽  
Mazen Alamir ◽  
Julien Pouget
Keyword(s):  
Performance Analysis ◽  
Frequency Domain ◽  
Low Frequency ◽  
Experimental Tests ◽  
Frequency Measurement ◽  
Phase Locked Loop ◽  
Frequency Domain Analysis ◽  
Loop Filter ◽  
Control Stability ◽  
Unbalanced Grid

AbstractAn extended state observer (ESO)-based loop filter is designed for the phase-locked loop (PLL) involved in a disturbed grid-connected converter (GcC). This ESO-based design enhances the performances and robustness of the PLL, and, therefore, improves control performances of the disturbed GcCs. Besides, the ESO-based LF can be applied to PLLs with extra filters for abnormal grid conditions. The unbalanced grid is particularly taken into account for the performance analysis. A tuning approach based on the well-designed PI controller is discussed, which results in a fair comparison with conventional PI-type PLLs. The frequency domain properties are quantitatively analysed with respect to the control stability and the noises rejection. The frequency domain analysis and simulation results suggest that the performances of the generated ESO-based controllers are comparable to those of the PI control at low frequency, while have better ability to attenuate high-frequency measurement noises. The phase margin decreases slightly, but remains acceptable. Finally, experimental tests are conducted with a hybrid power hardware-in-the-loop benchmark, in which balanced/unbalanced cases are both explored. The obtained results prove the effectiveness of ESO-based PLLs when applied to the disturbed GcC.

scholarly journals Low frequency of LRV1 in Leishmania braziliensis strains isolated from typical and atypical lesions in the State of Minas Gerais, Brazil

2016 ◽  
Vol 210 (1-2) ◽  
pp. 50-54 ◽  
Author(s):  
Diego H. Macedo ◽  
Armando Menezes-Neto ◽  
Jeronimo M. Rugani ◽  
Ana C. Rocha ◽  
Soraia O. Silva ◽  
...  
Keyword(s):  
Low Frequency ◽  
Minas Gerais ◽  
The State ◽  
Leishmania Braziliensis

scholarly journals Water Level Sensing in a Steel Vessel Using A0 and Quasi-Scholte Waves

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Peng Guo ◽  
Bo Deng ◽  
Xiang Lan ◽  
Kaili Zhang ◽  
Hongyuan Li ◽  
...  
Keyword(s):  
Water Level ◽  
Guided Waves ◽  
Mode Conversion ◽  
Experimental Studies ◽  
Low Frequency ◽  
Steel Vessel ◽  
Theoretical Predictions ◽  
Travelling Time ◽  
The Comparative Study ◽  
Group Velocities

This paper presents a water level sensing method using guided waves of A0 and quasi-Scholte modes. Theoretical, numerical, and experimental studies are performed to investigate the properties of both the A0 and quasi-Scholte modes. The comparative study of dispersion curves reveals that the plate with one side in water supports a quasi-Scholte mode besides Lamb modes. In addition, group velocities of A0 and quasi-Scholte modes are different. It is also found that the low-frequency A0 mode propagating in a free plate can convert to the quasi-Scholte mode when the plate has one side in water. Based on the velocity difference and mode conversion, a water level sensing method is developed. For the proof of concept, a laboratory experiment using a pitch-catch configuration with two piezoelectric transducers is designed for sensing water level in a steel vessel. The experimental results show that the travelling time between the two transducers linearly increases with the increase of water level and agree well with the theoretical predictions.

The effect of removing dental plaque with low-frequency ultrasound and ozonized contact medium on the microbiota of the gingival sulcus with diagnosis chronic catarrhal gingivitis of young age patients

2021 ◽  
pp. 98-101
Author(s):  
G. R. Mhoyan ◽  
S. N. Razumova ◽  
A. G. Volkov ◽  
N. Zh. Dikopova ◽  
A. G. Ponomareva ◽  
...  
Keyword(s):  
Young People ◽  
Dental Plaque ◽  
Low Frequency ◽  
The State ◽  
Young Age ◽  
Transient Species ◽  
Resident Species ◽  
Low Frequency Ultrasound ◽  
Frequency Ultrasound ◽  
Ozonated Water

As a result of the study, it was found that the removal of dental plaque using low-frequency ultrasound and ozonized contact medium in chronic generalized catarrhal gingivitis of young people can significantly improve the state of microbiocenosis of the gingival sulcus. The preservation of the main resident species is noted, occasional transient species disappear and the frequency of isolation of aggressive representatives of beta-hemolytic streptococci and periodontopathogenic species decreases. When using ozonated water for the removal of dental deposits, the efficiency of eradication of the microbiota of the gingival sulcus, especially of representatives of aggressive species, is higher than when removing dental deposits without the use of ozonated water.

On vibration isolation of sandwich plate with periodic hollow tube core

2017 ◽  
Vol 21 (3) ◽  
pp. 1119-1132 ◽  
Author(s):  
Gui-Lan Yu ◽  
Hong-Wei Miao
Keyword(s):  
Vibration Isolation ◽  
Sandwich Plate ◽  
Experimental Studies ◽  
Low Frequency ◽  
Dispersion Relations ◽  
Frequency Responses ◽  
Vibration Attenuation ◽  
Potential Applications ◽  
Vibration Isolation Performance ◽  
Isolation Performance

The vibration isolation performance of a PC sandwich plate with periodic hollow tube core is investigated experimentally and numerically. The experiment results reveal that there exist vibration attenuation zones in acceleration frequency responses which can be improved by increasing the number of periods or tuning some structure parameters. The presence of soft fillers shifts the attenuation zone to lower frequencies and enhances the capability of vibration isolation to some extent. Dispersion relations and acceleration frequency responses are calculated by finite element method using COMSOL MULTIPHYSICS. The attenuation zones obtained by experiments fit well with that by simulations, and both are consistent with the band gap in dispersion relations. The numerical and experimental studies in the present paper show that this PC sandwich plate exhibits a good performance on vibration isolation in low frequency ranges, which will provide some useful references for relevant research and potential applications in vibration propagation manipulations.

scholarly journals Bird richness and composition in a Cerrado fragment in the State of São Paulo

2010 ◽  
Vol 70 (2) ◽  
pp. 243-254 ◽  
Author(s):  
LT Manica ◽  
M Telles ◽  
MM Dias
Keyword(s):  
Conservation Status ◽  
Bird Species ◽  
Low Frequency ◽  
Bird Community ◽  
Sao Paulo ◽  
The State ◽  
São Paulo ◽  
Conservation Area ◽  
Tropical Regions ◽  
Bird Richness

Bird species richness is an important measure for monitoring biodiversity changes. We analysed avifauna richness and composition in a 472 ha protected cerrado fragment and surroundings at Fazenda Canchim (RL-CPPSE), São Carlos, in the State of São Paulo (SP). We carried out 95.1 hours of observation (22 visits) at irregular intervals from May 2004 to December 2006. Qualitative surveys were done walking through tracks inside the fragment and on the roads at its edge. We recorded 160 species, six of which were endemic to Cerrado domain, 22 migratory, seven threatened within the State of São Paulo, and two globally threatened. We found 28 species in the cerradão, 110 in the cerrado sensu stricto, 13 in the gallery forest, 26 in the reservoir border, 26 in pasturelands and sugar cane monoculture and 55 in an anthropic area. Most of the species had low frequency of occurrence in all vegetation forms. Insectivores were the major trophic category (46.9%), which is typical in tropical regions, and it is also related to resource availability. Omnivores followed with 19.4%, granivores with 8.8% and frugivores with 7.5%. We conclude that, despite its size and conservation status, our study area has a remarkable bird community and must be considered as a priority conservation area to preserve bird species in Sao Paulo State.

scholarly journals RESEARCH OF THE INFLUENCE OF ELECTROMAGNETIC FIELDS AND OPTICAL CHARACTERISTICS OF THE ENVIRONMENT ON THE BEHAVIOR OF THESE SEALS

2020 ◽  
Vol 11 (4) ◽  
pp. 214-225
Author(s):  
A.A. Zaitsev ◽  
◽  
A.P. Yakovlev ◽  
M.V. Pakhomov ◽  
◽  
...  
Keyword(s):  
Electromagnetic Fields ◽  
Experimental Studies ◽  
The State ◽  
Optical Characteristics

This paper presents the generalized results of experimental studies on the influence of electromagnetic fields and optical characteristics of the medium on the behavior of real seals conducted by the biotechnological systems laboratory of the MMBI RAS as part of the state task.

scholarly journals CORRUPTION AS A THREAT TO THE ECONOMIC SECURITY OF RUSSIA

2018 ◽  
Author(s):  
Галина Крохичева ◽  
Galina Krohicheva ◽  
Дмитрий Брязгунов ◽  
Dmitri Bryzgunov
Keyword(s):  
National Security ◽  
Economic Security ◽  
The State ◽  
External Factors ◽  
Criminal Offense ◽  
Negative Factor ◽  
National Priority ◽  
Great Danger

. Ensuring economic security is the independence of the country and the condition for the life of society. That is why economic security is a top national priority. In modern Russia, there are both external and internal threats to the country's economic security. Internal threats pose a great danger; it is their presence that makes the state more vulnerable to external factors. Corruption in our country acts as a form of manifestation of internal threats. This powerful negative factor violates the safety of economic and national security. Corruption occurs in the industry where the criminal has various privileges and powers. At the same time, this crime causes greater economic harm to a citizen, society and the state than any other criminal offense.

scholarly journals Formation of an Innovative Business Model of a Trade Organization in the Context of Economic Globalization

2021 ◽  
Vol 24 (6) ◽  
pp. 92-98
Author(s):  
Pavlo Hrynko ◽  
Alla Grinko ◽  
Tatyana Shtal ◽  
Hanna Radchenko ◽  
Mariia Pokolodna
Keyword(s):  
Business Models ◽  
State Regulation ◽  
The State ◽  
Retail Trade ◽  
External Factors ◽  
Business Strategies ◽  
Sharp Change ◽  
Innovation Potential ◽  
Innovation Activities ◽  
The Impact

The development of Ukrainian trade organizations in ordinary conditions is characterized by a high degree of inertia. Therefore, when situations that need to change arise, business strategies of market participants also change dramatically. Most often, such transformations are connected with external factors, such as the overall economic crisis, a sharp change in the state “rules of the game” in a particular sector of economic relations, as well as another external factor bond to the occurrence of new serious competitors. The development of organizational and economic mechanism to ensure the innovative development of retail trade, requires comprehensive consideration of internal and external factors of the studied system, the formation of strategies and programs to increase the innovation potential of its participants, their active interaction, increasing the use of innovative technologies, generating ideas and transformations. The article considers the issues related to the impact of business globalization processes on the transformation of business models of trade organizations and their operation strategy, as the degree of trade development indicates the standard of living and the state of the economy and society. The authors of the article suggest that retail organizations adapt to the changes in the macro and micro environment, using innovative components in economic and financial activities, which will ensure their competitiveness and prevent crises. The proposed model of an innovative trade organization allows to identify the goals components of innovation activities, which combine the strategic guidelines of the state regulation and help to improve the economic condition of trade organizations

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