scholarly journals Deformation waves from distant earthquakes as a trigger mechanism for activating geodynamic processes in rock mass

2020 ◽  
Vol 192 ◽  
pp. 01022
Author(s):  
Vladimir Lugovoy ◽  
Denis Tsoi ◽  
Maksim Rasskazov ◽  
Kamchibek Kozhogulov
Keyword(s):  
Rock Mass ◽  
Experimental Studies ◽  
Low Frequency ◽  
Pressure Control ◽  
Trigger Mechanism ◽  
Geoacoustic Emission ◽  
Before And After ◽  
Geodynamic Processes ◽  
Pressure Control System ◽  
Geodynamic Activity

The results of experimental studies with a laser strainmeter and a multichannel automated geoacoustic rock pressure control system “PROGNOZ ADS” aimed at identifying the nature of the effect of deformation waves from distant earthquakes on the geodynamic activity of the monitored rock mass are presented. The quantitative and energy characteristics of geoacoustic emission before and after the arrival of deformation waves in the controlled rock mass are analyzed. The analysis performed indicates a trigger mechanism of the influence of a distant earthquake on the geodynamic activity of the rock mass. It is noted that the direction of arrival of the deformation wave is an essential factor in the intensification of geodynamic activity in the rock mass. The experiments also revealed the characteristics of rock burst precursors when registering deformation waves in the low-frequency range.

THE EXPERIENCE OF PLUGGING A MINE SHAFT UNDER CONDITIONS OF MANIFESTATION OF MODERN GEODYNAMIC ACTIVITY

2021 ◽  
Vol 4 (1) ◽  
pp. 341-351
Author(s):  
T.Sh. Dalatkazin ◽  
Keyword(s):  
Rock Mass ◽  
Water Pressure ◽  
Rock Massif ◽  
Entire Period ◽  
Mine Shaft ◽  
Significant Volume ◽  
Expected Result ◽  
Geodynamic Processes ◽  
Backfill Materials ◽  
Geodynamic Activity

The paper presents the results of studying of the effectiveness of water pressure in the shaft of a mine with the use of grouting are presented. The enclosing rock massif is character-ized by simple hydrogeological conditions and moderate manifestation of modern geodynamic activity. Despite the significant volume of the performed backfill measures, the expected result was not obtained due to the underestimation of modern geodynamic processes when choosing the backfill materials. In the conditions of a geodynamically active rock mass, the plugging ma-terial must retain plasticity throughout the entire period of operation.

Effect of pentobarbital anesthesia on hypotension after 10% hemorrhage in the dog

1979 ◽  
Vol 236 (4) ◽  
pp. H607-H612 ◽  
Author(s):  
H. Hosomi ◽  
K. Sagawa
Keyword(s):  
Control System ◽  
Arterial Pressure ◽  
Peripheral Resistance ◽  
Pressure Control ◽  
Pentobarbital Anesthesia ◽  
Significant Difference ◽  
Before And After ◽  
Intact Condition ◽  
Pressure Control System ◽  
Arterial Pressure Control System

The effect of pentobarbital anesthesia, 30 mg.kg body wt-1, on the rapidly acting arterial pressure control system was studied on splenectomized dogs chronically instrumented with catheters for pressure measurement and hemorrhage and with a flow probe for measurement of aortic flow. The dogs were subjected to 10% hemorrhage in 30 s under conscious and anesthetized states before and after denervation of the carotid sinus nerves (CS) and/or the vagi (V). In the intact nerve condition, arterial pressure fall (delta AP) at 1-2 min after hemorrhage was 8.0 +/- 1.3 (mean +/- SE) mmHg in conscious dogs and 9.4 +/- 2.0 mmHg in dogs under anesthesia. There was no significant difference between these delta APs or other pairs of delta APs in conscious and anesthetized states at any stage of denervation. As long as the CS reflex was intact, heart rate and total peripheral resistance increased in response to hemorrhage as in the intact condition. In conclusion, the pentobarbital anesthesia had little effect on the rapidly acting arterial pressure control system as far as its capacity to restore mean arterial pressure after the brief 10% hemorrhage is concerned.

Experimental Studies on Pressure Control Using Intelligent PI Fuzzy Supervisory Approach

2008 ◽  
Vol 4 (2) ◽  
Author(s):  
Palani Sivashanmugam ◽  
N. Kanagaraj ◽  
R. Kumar
Keyword(s):  
Control Method ◽  
Fuzzy Controller ◽  
Experimental Studies ◽  
Pressure Control ◽  
Operating Conditions ◽  
Real Time Control ◽  
Time Control ◽  
Executable File ◽  
Pressure Control System ◽  
Tank Pressure

Fuzzy supervisory control scheme for regulating the tank pressure in a pilot pressure control system has been presented. The controller structure has been designed in such a way as to adjust on-line the parameters of a classical PI controller that will reduce the human involvement in tuning the controller parameters at different operating conditions. The control algorithm for the proposed scheme has been developed using KEIL software and then converted into an executable file before downloading it to an ARM7 (AT91M55800A) based embedded target board. The pipeline execution and RISC architecture of ARM7 target board enhances the computation speed in real time control applications. Experimental study has been carried out to test the performance of the proposed supervisory fuzzy controller and the results were compared with classical control method. Better control performance using supervisory fuzzy controller has been obtained.

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.

PRESSURE CONTROL SYSTEM AT CEMENTATION OF WELLS

2017 ◽  
pp. 62-67
Author(s):  
V. G. Kuznetsov ◽  
O. A. Makarov
Keyword(s):  
Control System ◽  
Oil And Gas ◽  
Pressure Control ◽  
Poor Quality ◽  
Technical Solution ◽  
Cement Slurry ◽  
Automated Control ◽  
Injection Speed ◽  
Pressure Control System ◽  
Effective Life

At cementing of casing of oil and gas wells during the process of injecting of cement slurry in the casing column the slurry can move with a higher speed than it’s linear injection speed. A break of continuity of fluid flow occurs, what can lead to poor quality isolation of producing formations and shorten the effective life of the well. We need to find some technical solution to stabilize the linear velocity of the cement slurry in the column. This task can be resolved with an automated control system.

scholarly journals Understanding sex differences in long-term blood pressure regulation: insights from experimental studies and computational modeling

2019 ◽  
Vol 316 (5) ◽  
pp. H1113-H1123 ◽  
Author(s):  
Sameed Ahmed ◽  
Rui Hu ◽  
Jessica Leete ◽  
Anita T. Layton
Keyword(s):  
Blood Pressure ◽  
Sex Differences ◽  
Computational Models ◽  
Experimental Studies ◽  
Pressure Control ◽  
Blood Pressure Regulation ◽  
Pressure Regulation ◽  
Physiological Processes ◽  
Key Players

Sex differences in blood pressure and the prevalence of hypertension are found in humans and animal models. Moreover, there has been a recent explosion of data concerning sex differences in nitric oxide, the renin-angiotensin-aldosterone system, inflammation, and kidney function. These data have the potential to reveal the mechanisms underlying male-female differences in blood pressure control. To elucidate the interactions among the multitude of physiological processes involved, one may apply computational models. In this review, we describe published computational models that represent key players in blood pressure regulation, and highlight sex-specific models and their findings.

scholarly journals Directional Hydraulic Fracturing (DHF) of the Roof, as an Element of Rock Burst Prevention in the Light of Underground Observations and Numerical Modelling

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 562
Author(s):  
Marek Jendryś ◽  
Andrzej Hadam ◽  
Mateusz Ćwiękała
Keyword(s):  
Rock Mass ◽  
Hydraulic Fracturing ◽  
Coal Mining ◽  
Rock Burst ◽  
Coal Mine ◽  
Seismic Activity ◽  
Black Coal ◽  
Directional Hydraulic Fracturing ◽  
Before And After ◽  
The Face

The following article analyzes the effectiveness of directional hydraulic fracturing (DHF) as a method of rock burst prevention, used in black coal mining with a longwall system. In order to define changes in seismic activity due to DHF at the “Rydułtowy” Black Coal Mine (Upper Silesia, Poland), observations were made regarding the seismic activity of the rock mass during coal mining with a longwall system using roof layers collapse. The seismic activity was recorded in the area of the longwall itself, where, on a part of the runway, the rock mass was expanded before the face of the wall by interrupting the continuity of the rock layers using DHF. The following article presents measurements in the form of the number and the shock energy in the area of the observed longwall, which took place before and after the use of DHF. The second part of the article unveils the results of numerical modeling using the discrete element method, allowing to track the formation of goafs for the variant that does not take DHF into consideration, as well as with modeled fractures tracing DHF carried out in accordance with the technology used at “Rydułtowy” coal mine.

Effects of activation frequency and force on low-frequency fatigue in human skeletal muscle

1999 ◽  
Vol 86 (4) ◽  
pp. 1337-1346 ◽  
Author(s):  
Stuart A. Binder-Macleod ◽  
David W. Russ
Keyword(s):  
Healthy Subjects ◽  
Human Skeletal Muscle ◽  
Low Frequency ◽  
Variable Frequency ◽  
Activation Pattern ◽  
Constant Frequency ◽  
Mean Frequency ◽  
Before And After ◽  
Low Frequency Fatigue ◽  
Force Time

No comparison of the amount of low-frequency fatigue (LFF) produced by different activation frequencies exists, although frequencies ranging from 10 to 100 Hz have been used to induce LFF. The quadriceps femoris of 11 healthy subjects were tested in 5 separate sessions. In each session, the force-generating ability of the muscle was tested before and after fatigue and at 2, ∼13, and ∼38 min of recovery. Brief (6-pulse), constant-frequency trains of 9.1, 14.3, 33.3, and 100 Hz and a 6-pulse, variable-frequency train with a mean frequency of 14.3 Hz were delivered at 1 train/s to induce fatigue. Immediately postfatigue, there was a significant effect of fatiguing protocol frequency. Muscles exhibited greater LFF after stimulation with the 9.1-, 14.3-, and variable-frequency trains. These three trains also produced the greatest mean force-time integrals during the fatigue test. At 2, ∼13, and ∼38 min of recovery, however, the LFF produced was independent of the fatiguing protocol frequency. The findings are consistent with theories suggesting two independent mechanisms behind LFF and may help identify the optimal activation pattern when functional electrical stimulation is used.

Sign in / Sign up

Export Citation Format

Share Document