scholarly journals Experimental Study of Blast-Induced Vibration Characteristics Based on the Delay-Time Errors of Detonator

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Ping Wang ◽  
Yuanjun Ma ◽  
Yongjian Zhu ◽  
Jun Zhu
Keyword(s):  
High Precision ◽  
Delay Time ◽  
Great Influence ◽  
Vibration Velocity ◽  
Blasting Vibration ◽  
Distribution Map ◽  
Allowable Error ◽  
The Difference ◽  
Electronic Detonator ◽  
Factor Variable

The delay-time of detonators in hole-by-hole blasting is generally calculated accurately considering they have great influence on the blasting effect, such as blasting vibration and blasting slungshot. The high-precision nonel detonator and digital electronic detonator are been commonly used because of their accuracy of delay-time. However, each detonator has an allowable error range of delay-time due to the difference in manufacturing process. In the initiation network, the errors of delay-time often accumulate gradually as the number of detonators increases. Therefore, theoretical delay-time and actual delay-time with error in the detonating network were discussed based on the delay-time errors of detonators. The single-factor variable method was used to carry out the comparative test in deep hole blasting. The results showed that the particle peak vibration velocity (PPV) was 13.1783 cm/s and 3.4856 cm/s with a drop of 73.55% in comparison with a nonel detonator and digital electronic detonator, which proved that hole-by-hole blasting in the high-precision nonel detonator network was not achieved due to the delay error of detonators. Furthermore, the location distribution map of holes where the same section of detonators might occur was obtained. Finally, the probability of blasting in the same section changes with the number of blast holes was discovered by theoretical analysis, which provided a basis for accurate hole-by-hole blasting.

scholarly journals Study on the Effect of Blasting Vibration on Rock Bolt and Shotcrete

2022 ◽  
Vol 2160 (1) ◽  
pp. 012077
Author(s):  
Yanlong Ren ◽  
Xuanli Yang ◽  
Chang Li ◽  
Mingzhe Lü ◽  
Jinzhao Zhuang
Keyword(s):  
Adverse Effects ◽  
Negative Impact ◽  
Great Influence ◽  
Time History ◽  
Construction Method ◽  
Rock Bolt ◽  
Vibration Velocity ◽  
Blasting Vibration ◽  
Finite Element Software ◽  
The Impact

Abstract The blasting tunneling construction method is often used in the underground engineering projects such as tunnels, coal mines roadway, chambers and so on, rock bolt and shotcrete support is used. Although the blasting construction method has many advantages, but also will be accompanied by adverse effects. Blasting vibration of blasting construction not only to the surrounding environment, building (structure) and other adverse effects, but also on the support of the underground project itself has a negative impact. In order to discuss the impact of blasting vibration on shotcrete and rock bolt support in the process of blasting tunneling of roadway, a certain amount of explosives is detonated in the hole of the working face, the finite element software ANSYS/LS-DYNA was used to establish the numerical calculation model, through time history analysis calculation, the distribution law of the vibration velocity on the shotcrete surface along the section and the variation law of the longitudinal tension and compression stress of the rock bolt are obtained. The results show that the blasting vibration produced by blasting tunneling has a great influence on the shotcrete at the shoulder, but little influence on the axial force of the rock bolt.

scholarly journals First in-orbit results of the vector magnetic field measurement of the High Precision Magnetometer onboard the China Seismo-Electromagnetic Satellite

2019 ◽  
Vol 71 (1) ◽  
Author(s):  
Bin Zhou ◽  
Bingjun Cheng ◽  
Xiaochen Gou ◽  
Lei Li ◽  
Yiteng Zhang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
High Precision ◽  
Magnetic Field Measurement ◽  
Vector Data ◽  
Magnetic Field Data ◽  
Night Side ◽  
The Difference ◽  
The Magnetic Field ◽  
Ground Calibration ◽  
Data Calibration

Abstract The High Precision Magnetometer (HPM) is one of the main payloads onboard the China Seismo-Electromagnetic Satellite (CSES). The HPM consists of two Fluxgate Magnetometers (FGM) and the Coupled Dark State Magnetometer (CDSM), and measures the magnetic field from DC to 15 Hz. The FGMs measure the vector components of the magnetic field; while the CDSM detects the magnitude of the magnetic field with higher accuracy, which can be used to calibrate the linear parameters of the FGM. In this paper, brief descriptions of measurement principles and performances of the HPM, ground, and in-orbit calibration results of the FGMs are presented, including the thermal drift and magnetic interferences from the satellite. The HPM in-orbit vector data calibration includes two steps: sensor non-linearity corrections based on on-ground calibration and fluxgate linear parameter calibration based on the CDSM measurements. The calibration results show a reasonably good stability of the linear parameters over time. The difference between the field magnitude calculated from the calibrated FGM components and the magnitude directly measured by the CDSM is just 0.5 nT (1σ) when the linear parameters are fitted separately for the day- and the night-side. Satellite disturbances have been analyzed including soft and hard remanence as well as magnetization of the magnetic torquer, radiation from the Tri-Band Beacon, and interferences from the rotation of the solar wing. A comparison shows consistency between the HPM and SWARM magnetic field data. Observation examples are introduced in the paper, which show that HPM data can be used to survey the global geomagnetic field and monitor the magnetic field disturbances in the ionosphere.

scholarly journals Experiment and Analysis of Wedge Cutting Angle on Cutting Effect

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Deqiang Yang ◽  
Xuguang Wang ◽  
Yinjun Wang ◽  
Huaming An ◽  
Zhen Lei
Keyword(s):  
Construction Cost ◽  
Economic Benefits ◽  
Tunneling Rate ◽  
Vibration Velocity ◽  
Utilization Rate ◽  
Engineering Practice ◽  
Blasting Vibration ◽  
Cutting Depth ◽  
Vertical Side ◽  
Cutting Angle

In the process of tunnel excavation, large charge wedge cutting blasting is widely used to improve the effect of cut blasting and speed up the excavation rate, which is tantamount to increasing the construction cost. In order to save economic cost and improve cutting blasting effect, wedge cutting models with five different cutting angles were experimented and studied by using concrete materials on the basis of similarity theory analysis. The relationships among cutting depth, blasting volume, blasting fragment, and cutting angle are studied and deduced by the dimensional analysis method. The polynomial fitting of cutting depth, blasting volume, blasting fragment, and cutting angle is carried out according to the experimental data, and the corresponding fitting formula is obtained. The optimum cutting depth, hole utilization rate, blasting volume, and blasting fragment were obtained when the wedge cutting angle was 67° under the same charge. The values were 1.665 × 10−1 m, 92.5%, 8.390 × 10−3 m3, and 49.07 mm, respectively. With the use of TC4850N type blasting vibration meter, the blasting vibrations on the wedge in four directions are tested and analyzed. The results show that when wedge cutting inclination is 65 degrees, the peak vibration velocity is the minimum and the vibration intensity of the wedge cutting inclined side is generally smaller than that of the vertical side. Considering the cutting depth, blasting volume, blasting fragment, blasting vibration hazard, drilling error, tunneling construction cost, and other factors, the 65°∼69° wedge cutting blasting in engineering practice can improve the blasting tunneling rate and increase economic benefits. The experimental results show that the blasting tunneling rate is increased and the economic benefit is increased with the minimum construction tunneling cost, which has certain engineering significance.

Influences of Tunnel Excavation Blasting Vibration on Surface High-Rise Building

2010 ◽  
Vol 163-167 ◽  
pp. 2613-2617
Author(s):  
Hai Liang Wang ◽  
Tong Wei Gao
Keyword(s):  
Vibration Frequency ◽  
Vertical Vibration ◽  
Frame Structure ◽  
Vibration Monitoring ◽  
Vibration Velocity ◽  
Blasting Vibration ◽  
Road Tunnel ◽  
Concrete Frame ◽  
High Rise ◽  
Order Of Magnitude

According to the 33 floors high building, blasting vibration monitoring had been carried on. The building, along Yunnan road tunnel of Qingdao Cross-harbor Tunnel Guide Line Project, has concrete frame structure. Monitoring data had been analyzed. Results showed that rules of vertical vibration velocity and main vibration frequency have similar relevance. Amplification effect of them was existed on the middle and top of the building. From the 2nd floor of downward ground to ground, the value of them suddenly decreased. Main vibration frequency is in the range of 101~102 order of magnitude.

INVESTIGATION OF THE ABSOLUTENESS OF TIME

2021 ◽  
pp. 51-54
Author(s):  
S. Tiguntsev
Keyword(s):  
High Precision ◽  
Gravitational Potential ◽  
High Speed ◽  
Relativistic Effect ◽  
Theoretical Research ◽  
Clock Frequency ◽  
Positioning Systems ◽  
The Earth ◽  
Flow Of Time ◽  
The Difference

In classical physics, time is considered absolute. It is believed that all processes, regardless of their complexity, do not affect the flow of time The theory of relativity determines that the flow of time for bodies depends both on the speed of movement of bodies and on the magnitude of the gravitational potential. It is believed that time in space orbit passes slower due to the high speed of the spacecraft, and faster due to the lower gravitational potential than on the surface of the Earth. Currently, the dependence of time on the magnitude of the gravitational potential and velocity (relativistic effect) is taken into account in global positioning systems. However, studying the relativistic effect, scientists have made a wrong interpretation of the difference between the clock frequency of an orbiting satellite and the clock frequency on the Earth's surface. All further studies to explain the relativistic effect were carried out according to a similar scenario, that is, only the difference in clock frequencies under conditions of different gravitational potentials was investigated. While conducting theoretical research, I found that the frequency of the signal changes along the way from the satellite to the receiver due to the influence of Earth's gravity. It was found that the readings of two high-precision clocks located at different heights will not differ after any period of time, that is, it is shown that the flow of time does not depend on the gravitational potential. It is proposed to conduct full-scale experiments, during which some high-precision clocks are sent aboard the space station, while others remain in the laboratory on the surface of the earth. It is expected that the readings of the satellite clock will be absolutely identical to the readings of the clock in the Earth laboratory.

Analysis on Kinematic Characteristics of Precision Balls Grinding

2012 ◽  
Vol 497 ◽  
pp. 20-24
Author(s):  
Yong Dai ◽  
Dong Hui Ding ◽  
Xu Xiao ◽  
Xue Shi Liu ◽  
Rui Jiang He ◽  
...  
Keyword(s):  
Numerical Analysis ◽  
Great Influence ◽  
Processing Parameters ◽  
Important Influence ◽  
Normal Movement ◽  
Motion State ◽  
Kinematic Characteristics ◽  
The Difference

In the process of grinding precision balls, the motion state of balls has an important influence on the efficiency and quality. However, the normal movement of balls will be damaged because of slipping, so it must be avoided. Besides, to process different materials of balls, it should use different processing parameters. This paper studies a numerical analysis on the kinematic characteristics of the motion of balls, analyzes processing parameters which impact the motion of balls during grinding and the difference of the motion state of bearing balls and resin balls. Study shows grinding pressure and plate speed have a great influence to the motion of balls during grinding.

scholarly journals Estimation of Delay Times in Coupling Between Autonomic Regulatory Loops of Human Heart Rate and Blood Flow Using Phase Dynamics Analysis

2017 ◽  
Vol 9 (1) ◽  
pp. 16-22 ◽  
Author(s):  
Vladimir S Khorev ◽  
Anatoly S Karavaev ◽  
Elena E Lapsheva ◽  
Tatyana A Galushko ◽  
Mikhail D Prokhorov ◽  
...  
Keyword(s):  
Heart Rate ◽  
Delay Time ◽  
Healthy Subjects ◽  
Low Frequency ◽  
Phase Dynamics ◽  
Oscillatory Systems ◽  
Low Frequency Oscillations ◽  
Delay Times ◽  
The Difference ◽  
Regulatory Loop

Objective: We assessed the delay times in the interaction between the autonomic regulatory loop of Heart Rate Variability (HRV) and autonomic regulatory loop of photoplethysmographic waveform variability (PPGV), showing low-frequency oscillations. Material and Methods: In eight healthy subjects aged 25–30 years (3 male, 5 female), we studied at rest (in a supine position) the simultaneously recorded two-hour signals of RR intervals (RRIs) chain and finger photoplethysmogram (PPG). To extract the low-frequency components of RRIs and PPG signal, associated with the low-frequency oscillations in HRV and PPGV with a frequency of about 0.1 Hz, we filtered RRIs and PPG with a bandpass 0.05-0.15 Hz filter. We used a method for the detection of coupling between oscillatory systems, based on the construction of predictive models of instantaneous phase dynamics, for the estimation of delay times in the interaction between the studied regulatory loops. Results: Averaged value of delay time in coupling from the regulatory loop of HRV to the loop of PPGV was 0.9±0.4 seconds (mean ± standard error of the means) and averaged value of delay time in coupling from PPGV to HRV was 4.1±1.1 seconds. Conclusion: Analysis of two-hour experimental time series of healthy subjects revealed the presence of delay times in the interaction between regulatory loops of HRV and PPGV. Estimated delay time in coupling regulatory loops from HRV to PPGV was about one second or even less, while the delay time in coupling from PPGV to HRV was about several seconds. The difference in delay times is explained by the fact that PPGV to HRV response is mediated through the autonomic nervous system (baroreflex), while the HRV to PPGV response is mediated mechanically via cardiac output.

A Fast Algorithm to Choose Delay Time for Strange Attractors

2011 ◽  
Vol 230-232 ◽  
pp. 1379-1383
Author(s):  
Peng Yao ◽  
Gai Rong Chen ◽  
Shao Hong Xu
Keyword(s):  
Mutual Information ◽  
High Precision ◽  
Satisfactory Result ◽  
Fast Algorithm ◽  
Delay Time ◽  
Traditional Method ◽  
Chaotic Systems ◽  
Phase State ◽  
State Reconstruction ◽  
Simulation Results

According to pseudo-periodicity and ergodicity of chaotic systems, we put forward a fast algorithm to determine delay time in phase state reconstruction. The traditional method to calculate mutual information is time-consuming and complicated to realize, which greatly restricts its application. In our algorithm we gradually reduce the feasible computing interval and adjust the calculating step until satisfactory result is gotten. This method overcomes the tedious calculation of mutual information and meanwhile guarantees high precision. Finally the simulation results of Rössler and Lorenz systems verify the feasibility of our algorithm.

scholarly journals The difference of delay time in monitoring system of facial acupressure learning media using bluetooth, wireless and ethernet

2018 ◽  
Author(s):  
Eny Widhia Agustin ◽  
Arimaz Hangga ◽  
Muhammad Iqbal Fahrian ◽  
Anis Fikri Azhari
Keyword(s):  
Monitoring System ◽  
Delay Time ◽  
The Difference

Performance Characteristics of Several Rules for Self-interpretation of Proficiency Testing Data

2005 ◽  
Vol 129 (8) ◽  
pp. 997-1003 ◽  
Author(s):  
R. Neill Carey ◽  
George S. Cembrowski ◽  
Carl C. Garber ◽  
Zohreh Zaki
Keyword(s):  
Proficiency Testing ◽  
Error Detection ◽  
Clinical Laboratory ◽  
Peer Group ◽  
Simulation Techniques ◽  
Allowable Error ◽  
Detection Capabilities ◽  
The Mean ◽  
The Difference

Abstract Context.—Proficiency testing (PT) participants can interpret their results to detect errors even when their performance is acceptable according to the limits set by the PT provider. Objective.—To determine which rules for interpreting PT data provide optimal performance for PT with 5 samples per event. Design.—We used Monte Carlo computer simulation techniques to study the performance of several rules, relating their error detection capabilities to (1) the analytic quality of the method, (2) the probability of failing PT, and (3) the ratio of the peer group SD to the mean intralaboratory SD. Analytic quality is indicated by the ratio of the PT allowable error to the intralaboratory SD. Failure of PT was defined (Clinical Laboratory Improvement Amendments of 1988) as an event when 2 or more results out of 5 exceeded acceptable limits. We investigated rules with limits based on the SD index, the mean SD index, and percentages of allowable error. Results.—No single rule performs optimally across the range of method quality. Conclusions.—We recommend further investigation when PT data cause rejection by any of the following 3 rules: any result exceeds 75% of allowable error, the difference between any 2 results exceeds 4 times the peer group SD, or the mean SD index of all 5 results exceeds 1.5. As method quality increases from marginal to high, false rejections range from 16% to nearly zero, and the probability of detecting a shift equal to 2 times the intralaboratory SD ranges from 94% to 69%.

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