scholarly journals Stability Mechanism and Control Factors on Equipment Removal Area under “Goaf-Roof-Coal” Structure

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Zhongshun Chen ◽  
Yong Yuan ◽  
Cheng Zhu ◽  
Wenmiao Wang
Keyword(s):  
Shear Failure ◽  
Longwall Mining ◽  
Control Measures ◽  
Failure Zone ◽  
Mining Equipment ◽  
Control Factors ◽  
Shallow Coal Seam ◽  
The Stability ◽  
Working Resistance ◽  
And Control

One of the main difficulties in longwall mining (LM) is the movement of mining equipment from one panel to the next panel during mining process. The shields of the LM face may be damaged by the collapse of the roof in shallow coal seam under the “Goaf-Roof-Coal” (GRC) structure, especially when moving the shields from the current panel to the next panel. In order to solve this problem, the stability mechanism and its control factors during the LM equipment removal were investigated by using comprehensive methods including theoretical analysis, numerical simulation, and field validation based on the working conditions of Panel 31102 in Liangshuijing Coal Mine. The numerical simulations demonstrate that four different failure zones, shear failure zone, tension failure zone, partly elastic zone, and plastic failure zone, appear around the area due to the position of rock and the arrangements of the supports. The shear failure zone, which is controlled by shield working resistance and roof supporting strength, is the main cause of the failure in the removal area. To minimize the shear failure zone, several measures such as optimizing the end position for LM face, decreasing the width of removal area, and increasing the amount of cable support were taken to ensure the stability of surrounding rock in removal area, which have successfully controlled the damage of roof and equipment in Panel 31102. The field observation confirms that the proposed stability mechanism and control measures are effective under GRC structure.

Protein synthesis is required for rapid degradation of tubulin mRNA and other deflagellation-induced RNAs in Chlamydomonas reinhardi

1986 ◽  
Vol 6 (1) ◽  
pp. 54-61
Author(s):  
E J Baker ◽  
L R Keller ◽  
J A Schloss ◽  
J L Rosenbaum
Keyword(s):  
Protein Synthesis ◽  
Transcriptional Control ◽  
Protein S ◽  
Protein Synthesis Inhibitors ◽  
Control Factors ◽  
Flagellar Proteins ◽  
The Stability ◽  
And Control

After flagellar detachment in Chlamydomonas reinhardi, there is a rapid synthesis and accumulation of mRNAs for tubulin and other flagellar proteins. Maximum levels of these mRNAs (flagellar RNAs) are reached within 1 h after deflagellation, after which they are rapidly degraded to their predeflagellation levels. The degradation of alpha- and beta-tubulin RNAs was shown to be due to the shortening of their half-lives after accumulation (Baker et al., J. Cell Biol. 99:2074-2081, 1984). Deflagellation in the presence of protein synthesis inhibitors results in the accumulation of tubulin and other flagellar mRNAs by kinetics similar to those of controls. However, unlike controls, in which the accumulated mRNAs are rapidly degraded, these mRNAs are stabilized in cycloheximide. The stabilization by cycloheximide is specific for the flagellar mRNAs accumulated after deflagellation, since there is no change in the levels of flagellar mRNAs in nondeflagellated (uninduced) cells in the presence of cycloheximide. The kinetics of flagellar mRNA synthesis after deflagellation are shown to be the same in cycloheximide-treated and control cells by in vivo labeling and in vitro nuclear runoff experiments. These results show that protein synthesis is not required for the induced synthesis of flagellar mRNAs, and that all necessary transcriptional control factors are present in the cell before deflagellation, but that protein synthesis is required for the accelerated degradation of the accumulated flagellar mRNAs. Since cycloheximide prevents the induced synthesis and accumulation of flagellar proteins, it is possible that the product(s) of protein synthesis required for the accelerated decay of these mRNAs is a flagellar protein(s). The possibility that one or more flagellar proteins autoregulate the stability of the flagellar mRNAs is discussed.

Stability Analysis and Control Measures of the Kim-Yun-Mine Collapse

2012 ◽  
Vol 594-597 ◽  
pp. 358-361
Author(s):  
Shan Shan Zhang ◽  
Yu Liang Wu
Keyword(s):  
Rock Mass ◽  
Stability Analysis ◽  
Stereographic Projection ◽  
Control Measures ◽  
Collapse Characteristics ◽  
Basic Characteristics ◽  
The Stability ◽  
Mine Collapse ◽  
And Control ◽  
Dangerous Rock Mass

Collapse is one of the major geological disasters all over the world and threats to life and property safety of people. To make a better understanding of the reason it occurs and how to deal with it, the Kim-Yun-Mine collapse is researched. There are one dangerous rock mass and two collapse accumulation body. The basic characteristics of the collapse is described clearly according to the geological exploration data, and the stability of the dangerous rock mass and the collapse accumulated body is analyzed in the way of engineering geology and stereographic projection. At last, we put forward comprehensive control measures based on the results of stability analysis and collapse characteristics.

scholarly journals Mechanical Modeling of Roof Fracture Instability Mechanism and Its Control in Top-Coal Caving Mining under Thin Topsoil of Shallow Coal Seam

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Peilin Gong ◽  
Tong Zhao ◽  
Kaan Yetilmezsoy ◽  
Kang Yi
Keyword(s):  
Coal Seam ◽  
Mechanical Model ◽  
Main Roof ◽  
Stability Control ◽  
Hydraulic Support ◽  
Rock Stability ◽  
Shallow Coal Seam ◽  
Minimum Height ◽  
The Stability ◽  
Working Resistance

This study aimed to explore the safe and efficient top-coal caving mining under thin topsoil of shallow coal seam (SCS) and realize the optimization of hydraulic support. Numerical simulation and theoretical analysis were used to reveal the stress distribution of the topsoil, the structure characteristics of the main roof blocks, and the development of the roof subsidence convergence. Step subsidence of the initial fractured main roof after sliding destabilization frequently existed, which seriously threatened the safety of the hydraulic supports. Hence, a mechanical model of the main roof blocks, where the topsoil thickness was less than the minimum height of the unloading arch, was established, and the mechanical criterion of the stability was achieved. The working resistance of the hydraulic support was calculated, and the reasonable type was optimized so as to avoid crushing accident. Findings of the present analysis indicated that the hydraulic support optimization was mainly affected by fractured main roof blocks during the first weighting. According to the block stability mechanical model based on Mohr–Coulomb criterion, the required working resistance and the supporting intensity were determined as 4899 kN and 0.58 MPa, respectively. The ZZF5200/19/32S low-position top-coal caving hydraulic support was selected for the studied mine and support-surrounding rock stability control of thin-topsoil SCS could be achieved without crushing accident.

Causes Analysis and Control Measures of Landslide on Expressway from Yangshuo to Pingle in Guangxi

2013 ◽  
Vol 353-356 ◽  
pp. 116-119
Author(s):  
Chan Juan Yu ◽  
Yu Dong Peng
Keyword(s):  
Transfer Coefficient ◽  
Reference Value ◽  
Control Measures ◽  
The Other ◽  
Retaining Structure ◽  
Treatment Measures ◽  
Stability Of Slope ◽  
The Stability ◽  
And Control ◽  
Coefficient Method

According to the analysis on engineering geological and hydrological conditions of landslide on expressway from Yangshuo to Pingle in Guangxi, the formation mechanism of the landslide was summarized. The stability of slope was analyzed by mechanical transfer coefficient method. Then two kinds of effective preventions and treatment measures are proposed: setting retaining structure after drainage, or unloading after drainage. These measures have reference value to the management of the other landslide.

scholarly journals Stability Analysis of Shallow and Bias Loess Tunnel Based on Finite Difference Method

2019 ◽  
Vol 131 ◽  
pp. 01027
Author(s):  
Li Yongbing ◽  
Binglei Li ◽  
Guanyu Hua ◽  
Xinran Jia ◽  
Yanqiao Chen ◽  
...  
Keyword(s):  
Finite Difference ◽  
Shear Failure ◽  
Surrounding Rock ◽  
Tunnel Construction ◽  
Failure Zone ◽  
Tunnel Face ◽  
Whole Process ◽  
The Earth ◽  
Practical Engineering ◽  
The Stability

Based on the Mohr-Coulomb elastic-plastic model and the practical engineering background of Mopanshan tunnel, this paper applies the finite-difference software FLAC3D to simulate and analyse the whole process of loess tunnel construction. Then, it analyses the stability of the surrounding rock and sup-port structure after partial excavation of the loess tunnel under the shallow burying and unsymmetrical load-ing condition. The study showed that in the absence of support, the shear failure occurred to the top/upper pilot tunnel of the tunnel face, the failure zone under tensile stress happened to the shallow soil of the earth surface, and the soil of tunnel face appeared to be damaged. Finally, according to the analysis results, a rea-sonable construction method suitable for the shallow and bias loess tunnel is determined.

Landslide Formation Mechanism and its Control Measures in Dabaolang

2014 ◽  
Vol 722 ◽  
pp. 419-422
Author(s):  
Peng Lv ◽  
Bao Yu Li ◽  
Yu Zhang ◽  
Yun Xun Zhang
Keyword(s):  
Prevention And Control ◽  
Evolutionary Process ◽  
Heavy Rain ◽  
Control Measures ◽  
Skid Resistance ◽  
Effective Prevention ◽  
Main Factors ◽  
Mechanism Of Landslide ◽  
The Stability ◽  
And Control

Through analyzing Dabaoliang geological characteristics, this paper discussed the factors of the mechanism of landslide in Dabaoliang area and simulated its evolutionary process. The paper could get some conclusions, and the factors of landslide are as follow: the stability of the slope which mainly composed by clastic rock not only depended on the performance of the mudstone layer but also the skid resistance of the sliding surface and the shape of slope. Under the influence of regional structure, the joint fissures which developed along the boundary of the landslide will connect the crack and benefit the permeation of the surface water. The heavy rain is one of the main factors caused the slope unstable and sliding. Provide effective prevention and control for prevention and control of projects.

scholarly journals Protein synthesis is required for rapid degradation of tubulin mRNA and other deflagellation-induced RNAs in Chlamydomonas reinhardi.

1986 ◽  
Vol 6 (1) ◽  
pp. 54-61 ◽  
Author(s):  
E J Baker ◽  
L R Keller ◽  
J A Schloss ◽  
J L Rosenbaum
Keyword(s):  
Protein Synthesis ◽  
Transcriptional Control ◽  
Protein S ◽  
Protein Synthesis Inhibitors ◽  
Control Factors ◽  
Flagellar Proteins ◽  
The Stability ◽  
And Control

After flagellar detachment in Chlamydomonas reinhardi, there is a rapid synthesis and accumulation of mRNAs for tubulin and other flagellar proteins. Maximum levels of these mRNAs (flagellar RNAs) are reached within 1 h after deflagellation, after which they are rapidly degraded to their predeflagellation levels. The degradation of alpha- and beta-tubulin RNAs was shown to be due to the shortening of their half-lives after accumulation (Baker et al., J. Cell Biol. 99:2074-2081, 1984). Deflagellation in the presence of protein synthesis inhibitors results in the accumulation of tubulin and other flagellar mRNAs by kinetics similar to those of controls. However, unlike controls, in which the accumulated mRNAs are rapidly degraded, these mRNAs are stabilized in cycloheximide. The stabilization by cycloheximide is specific for the flagellar mRNAs accumulated after deflagellation, since there is no change in the levels of flagellar mRNAs in nondeflagellated (uninduced) cells in the presence of cycloheximide. The kinetics of flagellar mRNA synthesis after deflagellation are shown to be the same in cycloheximide-treated and control cells by in vivo labeling and in vitro nuclear runoff experiments. These results show that protein synthesis is not required for the induced synthesis of flagellar mRNAs, and that all necessary transcriptional control factors are present in the cell before deflagellation, but that protein synthesis is required for the accelerated degradation of the accumulated flagellar mRNAs. Since cycloheximide prevents the induced synthesis and accumulation of flagellar proteins, it is possible that the product(s) of protein synthesis required for the accelerated decay of these mRNAs is a flagellar protein(s). The possibility that one or more flagellar proteins autoregulate the stability of the flagellar mRNAs is discussed.

scholarly journals Design and Implementation of a Quadcopter Based on a Linear Quadratic Regulator (LQR)

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Amevi Acakpovi ◽  
François-Xavier Fifatin ◽  
Maurel Aza-Gnandji ◽  
François Kpadevi ◽  
Justice Nyarko
Keyword(s):  
Coastal Zone Management ◽  
Linear Quadratic Regulator ◽  
Control Measures ◽  
The Internet ◽  
Linear Quadratic ◽  
Infrastructure Monitoring ◽  
Zone Management ◽  
Forestry Management ◽  
The Stability ◽  
And Control

This paper presents the design and construction and control of a quadcopter drone for Aerial Data Collection (ADC). The frame of the drone was designed using CadDian Software and the parts were printed using a 3D printer. The flight controller was based on Arduino board using an Atmega328p microprocessor with GSM, GPS and GPRS for sending data over the internet and also enhancing long range flight. A feedback control system was developed and tested to control the stability of drone. The proposed control strategy of the drone was tested for a case of pursuit of trajectory and also for speed of response and the findings were very positive confirming the appropriateness of the control measures for independent and autonomous flying with promising precision. This Unmanned Aerial Vehicle (UAV) fitted with IoT has the capability of collecting and sending data over the internet and therefore can be used in many applications including risk assessment, forestry management, urban planning, coastal zone management, infrastructure monitoring, post-disaster damage assessment and delivery of medical supplies.

scholarly journals A close-loop verification approach for pedestrian stability based on machine vision

2022 ◽  
Vol 355 ◽  
pp. 03037
Author(s):  
Rongyong Zhao ◽  
Ping Jia ◽  
Yan Wang ◽  
Cuiling Li ◽  
Yunlong Ma ◽  
...  
Keyword(s):  
Numerical Analysis ◽  
Machine Vision ◽  
Lyapunov Theory ◽  
Control Measures ◽  
System Stability ◽  
Random Errors ◽  
Public Places ◽  
Crowd Management ◽  
The Stability ◽  
And Control

In public places, it is significant to analyze the stability of the crowd which can support the crowd management and control, and protect the evacuees safely and effectively. The numerical analysis method of system stability based on Lyapunov theory suffers problems that it is difficult to avoid random errors in the initialization of pedestrian density and velocity, as well as cumulative errors due to time increasing, limiting its application. This study adopts a complementary model of theoretical numerical analysis and machine vision with a parallel convolutional neural network (CNN) model. It proposes an approach of stability analysis and closed-loop verification for crowd merging systems. Thereby, this research provides theoretical and methodological support for planning of the functional layout of crowd flow in public crowd-gathering places and the control measures for stable crowd flow.

scholarly journals Identification and Control of Game-Based Epidemic Models

Games ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 10
Author(s):  
Dario Madeo ◽  
Chiara Mocenni
Keyword(s):  
High Performance ◽  
Evolutionary Games ◽  
Point Of View ◽  
Control Measures ◽  
Strategic Decision ◽  
Control Parameters ◽  
Estimated Parameters ◽  
Proposed Model ◽  
The Stability ◽  
And Control

The effectiveness of control measures against the diffusion of the COVID-19 pandemic is grounded on the assumption that people are prepared and disposed to cooperate. From a strategic decision point of view, cooperation is the unreachable strategy of the Prisoner’s Dilemma game, where the temptation to exploit the others and the fear of being betrayed by them drives the people’s behavior, which eventually results in a fully defective outcome. In this work, we integrate a standard epidemic model with the replicator equation of evolutionary games in order to study the interplay between the infection spreading and the propensity of people to be cooperative under the pressure of the epidemic. The developed model shows high performance in fitting real measurements of infected, recovered and dead people during the whole period of COVID-19 epidemic spread, from March 2020 to September 2021 in Italy. The estimated parameters related to cooperation result to be significantly correlated with vaccination and screening data, thus validating the model. The stability analysis of the multiple steady states present in the proposed model highlights the possibility to tune fundamental control parameters to dramatically reduce the number of potential dead people with respect to the non-controlled case.

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