scholarly journals DEVELOPMENT OF METHODS AND MANAGEMENT TOOLS AEROGASDYNAMICS PROCESSES AT MINING SITES

2021 ◽  
Vol 13 (1) ◽  
pp. 77-83
Author(s):  
Igor BOSIKOV ◽  
◽  
Roman KLYUEV ◽  
Valery KHETAGUROV ◽  
Iskandar AZHMUKHAMEDOV ◽  
...  
Keyword(s):  
Correlation Analysis ◽  
Dynamic Characteristics ◽  
Methane Concentration ◽  
Mine Ventilation ◽  
Static Characteristic ◽  
Normal Operation ◽  
Static Characteristics ◽  
Management Tools ◽  
Mining Sites ◽  
Method Of Correlation

The practical development of the algorithm for optimal control of mine ventilation was preceded by comprehensive studies of the specific features of mining sites in order to obtain their mathematical description. The latter includes the static and dynamic characteristics of objects, i.e. the relationship between input and output values. The purpose of the research: to develop methods and management tools aerogasdynamics processes on mining sites of coalmines. Research methods. The methodology based on the system approach; modern methods of mathematical statistics, decision theory; mathematical logic devices; factor analysis; mathematical modeling; set theory and system analysis. To determine the dynamic characteristics of aerogasodynamic processes, experimental methods were used, divided into active and passive. The active method consists in con-structing a dynamic model of airing objects by approximating the transition curve obtained because of special effects on the airing object with an analytical expression. Statistical dynamics methods were used to obtain dynamic characteristics based on normal operation data. The method of correlation analysis was used. Results of research: experimental verification showed that the maximum relative error of in determining the methane concentration from the static characteristic constructed using a modified technique does not exceed 10 %. The value of the error was determined by comparing the static characteristic obtained by the modified correlation analysis method with the exact static characteristic of the airing object. The latter were found with regard to dynamic properties of the object and additive structures aerogas dynamics processes. Conclusion. The method of correlation analysis can be used to determine the dependence of the methane flow rate on the airflow rate in the steady-state mode, i.e. the static characteristic q = f (Q) for the site and lava. To determine the static characteristics based on the data of normal operation with a limited observation interval (5-10 days), a modified method of correlation analysis is proposed. Small values of the relative error of indicate the possibility and feasibility of using a modified correlation analysis technique to construct a static characteristic of the airing object based on random processes of methane concentration and air flow obtained during normal operation of the site. The static characteristics C= f (Q) and q= f(Q) are widely used to determine the mathematical expectations of the methane concentration and flow rate of mining sites, in the modeling of ventilation facilities and in the analysis and synthesis of mine ventilation control systems.

On Obtaining Dynamic and Static Characteristics of Heavy Load Deflection Angle Milling Head by CAE and Experiment Techniques

2010 ◽  
Vol 156-157 ◽  
pp. 771-777
Author(s):  
Li Gang Cai ◽  
Shi Ming Ma ◽  
Zhi Feng Liu ◽  
Qiang Cheng ◽  
Yong Sheng Zhao
Keyword(s):  
Dynamic Characteristics ◽  
Degrees Of Freedom ◽  
Deflection Angle ◽  
Influence Factors ◽  
Static Characteristic ◽  
Free Form ◽  
Static Characteristics ◽  
Cnc Machine ◽  
Heavy Load ◽  
Cae Analysis

The heavy load deflection angle milling head is an important functional component of 5-axis CNC machine tool, which is used for large and complex free-form surface processing. The characteristics of this kind of milling head are implementing multiple degrees of freedom motion with revolution and deflection angle simultaneously. Obtaining milling head dynamic and static characteristics is a pre-requisite problem to resolve for the development and research of heavy load deflection angle milling head independently. Dynamic characteristics are obtained through combination with CAE (Computer-aided Engineering) technique and experiment validation. For CAE analysis, the main parts of milling head are glued together considering milling head operating at a specific position. Experimental validation is carried through with initial fixing constraint style, which validates the correctness of CAE technique. Experimental and CAE analysis results are compared and analyzed. Therefore, exact dynamic characteristics of milling head and unsubstantial segments and its influence factors are gotten. Static characteristic is obtained considering milling head operating in different posture by CAE technique. The analytical method of three points at half of cutter are loaded is introduced. Calculated results indicate that the deformation of tool tip is the largest when milling head operating in 45° posture, which corresponds with the deformation situation of the milling head operating in workshop. The analytical results of dynamic and static characteristics of milling head provide theoretical and experimental support for structure optimization and improving of heavy load deflection angle milling head.

scholarly journals Smoke recognition network based on dynamic characteristics

2020 ◽  
Vol 17 (3) ◽  
pp. 172988142092566
Author(s):  
Dahan Wang ◽  
Sheng Luo ◽  
Li Zhao ◽  
Xiaoming Pan ◽  
Muchou Wang ◽  
...  
Keyword(s):  
Dynamic Characteristics ◽  
State Of The Art ◽  
The State ◽  
Detection Accuracy ◽  
Static Characteristics ◽  
Good Tool ◽  
Early Signal ◽  
Fuzzy Objects ◽  
The Difference ◽  
Smoke Recognition

Fire is a fierce disaster, and smoke is the early signal of fire. Since such features as chrominance, texture, and shape of smoke are very special, a lot of methods based on these features have been developed. But these static characteristics vary widely, so there are some exceptions leading to low detection accuracy. On the other side, the motion of smoke is much more discriminating than the aforementioned features, so a time-domain neural network is proposed to extract its dynamic characteristics. This smoke recognition network has these advantages:(1) extract the spatiotemporal with the 3D filters which work on dynamic and static characteristics synchronously; (2) high accuracy, 87.31% samples being classified rightly, which is the state of the art even in a chaotic environments, and the fuzzy objects for other methods, such as haze, fog, and climbing cars, are distinguished distinctly; (3) high sensitiveness, smoke being detected averagely at the 23rd frame, which is also the state of the art, which is meaningful to alarm early fire as soon as possible; and (4) it is not been based on any hypothesis, which guarantee the method compatible. Finally, a new metric, the difference between the first frame in which smoke is detected and the first frame in which smoke happens, is proposed to compare the algorithms sensitivity in videos. The experiments confirm that the dynamic characteristics are more discriminating than the aforementioned static characteristics, and smoke recognition network is a good tool to extract compound feature.

scholarly journals Dynamic Modeling and Characteristic Analysis of Cantilever Piezoelectric Bimorph

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Heng Chen ◽  
Jun-shan Wang ◽  
Chao Chen ◽  
Shi-xiang Liu ◽  
Hai-peng Chen
Keyword(s):  
Axial Force ◽  
Dynamic Characteristics ◽  
Dynamic Equations ◽  
Steady State Response ◽  
Static Characteristics ◽  
Piezoelectric Bimorph ◽  
Characteristic Analysis ◽  
Generalized Coordinates ◽  
State Response ◽  
Millisecond Range

The analytical model of an axially precompressed cantilever bimorph is established using the Hamilton’s principle in this study, and the static characteristics are obtained. The dynamic equations of the cantilever bimorph in generalized coordinates are established using a numerical method, and the dynamic characteristics are analyzed. Finally, simulations are performed and experiments are conducted to verify the validity of the theory. The results show that increase of axial force has significant amplification effects on the steady-state response amplitude of the displacement, and it reduces the resonance frequency. The response time is still in the millisecond range under a large axial force, which indicates that the bimorph has excellent dynamic characteristics as an actuator.

A Design of the Network Security Evaluation System

2014 ◽  
Vol 686 ◽  
pp. 458-462
Author(s):  
Zi Yan Shi ◽  
Guo Lin Zhao ◽  
Qiao Lin Hu
Keyword(s):  
Network Security ◽  
Evaluation System ◽  
Evaluation Method ◽  
Evaluation Model ◽  
Normal Operation ◽  
Management Tool ◽  
Security Evaluation ◽  
Security Risk ◽  
Security Threat ◽  
Management Tools

The security evaluation for an information network system is an important management tool to insure its normal operation. We must realize the significance of the comprehensive network security risks. A network evaluation model and the algorithm are presented and adapt the hierarchical method to characterize the security risk situation. The evaluation method is used to evaluate the key nodes and the mathematics is used to analyze the whole network security situation. Compared with others, the method can automatically create a rule-based security evaluation model to evaluate the security threat from the individual security elements and the combination of security elements, and then evaluation the network situation. It is shown that this system provides a valuable model and algorithms to help to find the security rules, adjust the security measure, improve the security performance and design the appropriate security risk evaluation and management tools.

scholarly journals Modeling and Analysis of Static and Dynamic Characteristics of Nonlinear Seat Suspension for Off-Road Vehicles

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Zhenhua Yan ◽  
Bing Zhu ◽  
Xuefei Li ◽  
Guoqiang Wang
Keyword(s):  
Vibration Isolation ◽  
Characteristic Curve ◽  
Real Zero ◽  
Low Frequency ◽  
Static Characteristic ◽  
Static Characteristics ◽  
Weight Changes ◽  
Road Vehicles ◽  
Seat Suspension ◽  
Performance Reduction

Low-frequency vibrations (0.5–5 Hz) that harm drivers occur in off-road vehicles. Thus, researchers have focused on finding methods to effectively isolate or control low-frequency vibrations. A novel nonlinear seat suspension structure for off-road vehicles is designed, whose static characteristics and seat-human system dynamic response are modeled and analyzed, and experiments are conducted to verify the theoretical solutions. Results show that the stiffness of this nonlinear seat suspension could achieve real zero stiffness through well-matched parameters, and precompression of the main spring could change the nonlinear seat suspension performance when a driver’s weight changes. The displacement transmissibility curve corresponds with the static characteristic curve of nonlinear suspension, where the middle part of the static characteristic curve is gentler and the resonance frequency of the displacement transmissibility curve and the isolation minimum frequency are lower. Damping should correspond with static characteristics, in which the corresponding suspension damping value should be smaller given a flatter static characteristic curve to prevent vibration isolation performance reduction.

Dynamic Analysis of an Offshore Platform With Excessive Vibration Under Wave Loading

2003 ◽  
Author(s):  
Chunyan Ji ◽  
Huajun Li ◽  
Shuqing Wang
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Dynamic Characteristics ◽  
Model Experiment ◽  
Offshore Platform ◽  
Normal Operation ◽  
Bohai Bay ◽  
Fe Modeling ◽  
Wave Loading ◽  
Relative Movement

An offshore platform of jacket type in Bohai Bay vibrates excessively under design environmental conditions, which has affected the normal operation of the platform. In order to mitigate the vibration of the platform, it is essential important to explore the cause of the vibration. So the objective of this study is to investigate the cause of the excessive vibration. In this paper, dynamic characteristics of the offshore platform are analyzed by numerical simulation using finite element (FE) modeling. To further verify the numerical results, a model experiment is conducted. Numerical and experimental results demonstrate that there are relative movement and impact between the piles and the jacket, i.e. the piles and the jacket didn’t connect well to an entity. It is this cause that the stiffness of the platform deceases and impact between piles and the jacket legs induce excessive vibration. And also the grouting measure is advised to reduce the vibration of the offshore platform according to the analysis results.

Experiment on Static Characteristics of the Braking Signal Transmitter

2014 ◽  
Vol 889-890 ◽  
pp. 479-482
Author(s):  
Peng Zhang ◽  
Li Nan Zhang ◽  
Hong Zhi Liu ◽  
De Chun Fu
Keyword(s):  
Calibration Curve ◽  
Static Characteristic ◽  
Maximum Pressure ◽  
Static Characteristics ◽  
Test Bed ◽  
Source Pressure ◽  
Gas Source ◽  
Inflection Points ◽  
Test Pressure ◽  
Working Principle

The braking signal transmitter is a major component of the EBS. The structure and working principle of a braking signal transmitter were introduced. The test bed of the braking signal transmitter was designed and built. The static characteristics of the braking signal transmitter were obtained by analyzing the test data. The inflection points and the slope of each segment curve obtained by the bed test are basically identical to the static characteristic calibration curve. The pressure does not reach the maximum pressure of the static characteristic calibration curve because the gas source pressure does not reach the required test pressure. Keywords: Braking signal transmitter, EBS, static characteristics, bed test.

Doping Concentration Optimization for Ultra-Low-Loss 4H-SiC Floating Junction Schottky Barrier Diode (Super-SBD)

2009 ◽  
Vol 615-617 ◽  
pp. 655-658 ◽  
Author(s):  
Chiharu Ota ◽  
Johji Nishio ◽  
Kazuto Takao ◽  
Tetsuo Hatakeyama ◽  
Takashi Shinohe ◽  
...  
Keyword(s):  
Schottky Barrier ◽  
Breakdown Voltage ◽  
Dynamic Characteristics ◽  
Figure Of Merit ◽  
Doping Concentration ◽  
Drift Region ◽  
Static Characteristics ◽  
Low Loss ◽  
Significant Lowering ◽  
Floating Layer

Previous simulation works and experiments on the loss of 4H-SiC floating junction Schottky barrier diodes (Super-SBDs) show that the loss is related to the doping concentration in the drift region and the pattern of the floating layer. The effect of the doping concentration for lowering the loss is characterized the breakdown voltage (Vbd) and the on-state resistances (RonS) of the Super-SBDs based on Baliga’s figure of Merit (BFOM). Experimental devices with two doping concentrations in the drift region are fabricated to investigate the static characteristics: Vbd and RonS. The Vbd of the Super-SBDs is close to the simulation result, near 3000 V. However the tendency of the Vbd by the doping concentration is not similar to the simulation result. And the RonS are about 3.22 mcm2 which is higher than that of simulation result. The doping concentration optimized in this study does not show significant lowering loss and the design of the floating layer in the termination region affect the low-loss static characteristics of the Super-SBD. In addition, adopting PiN structure with floating layer (Super-PiN) affects the low-loss dynamic characteristics, optimizing the doping concentration in the drift region. We conclude that the fabricated Super-SBDs with the floating layer in the termination region, the drift region with a doping concentration of 1.01016 cm-3 and mesa-shaped termination structure, have excellent Vbd of 2990 V which is almost same as that of simulation result and RonS of 3.22 mcm2.

Mathematical Model of Attaching Sleeve Based on the Change of Underarm Point

2011 ◽  
Vol 331 ◽  
pp. 611-615
Author(s):  
Yong Mei Liu ◽  
Lu Zhang ◽  
Gan Hong Feng
Keyword(s):  
Mathematical Model ◽  
Regression Analysis ◽  
Correlation Analysis ◽  
Three Dimensional ◽  
Morphological Characteristics ◽  
Horizontal Displacement ◽  
Regression Equation ◽  
Factors Affecting ◽  
Three Dimensional Configuration ◽  
Method Of Correlation

Armhole is a base part of the sleeve. The sleeve morphological characteristics affect the construction and shape of sleeve. The underarm point is one of key restraining factors affecting armhole’s three-dimensional configuration. The experiments of armhole’s three-dimensional configuration and attaching sleeve experiments were designed according to the changes of the vertical and horizontal displacement of underarm point. The regression equation is established through the method of correlation analysis and regression analysis.

The Modeling and Simulation of Pneumatic ABS Pressure Regulator Based on AMESim

2014 ◽  
Vol 971-973 ◽  
pp. 811-815 ◽  
Author(s):  
Tian Fei Ma ◽  
Qian Chen
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Modeling And Simulation ◽  
Simulation Model ◽  
Dynamic Characteristics ◽  
Commercial Vehicle ◽  
Static Characteristics ◽  
Pressure Regulator ◽  
Characteristic Curves ◽  
Good Agreement

The pneumatic ABS pressure regulator of commercial vehicle is submitted to study in this paper. Its structure and operating principle are introduced, and a simulation model based on the AMESim is established on the basis of its mathematical model. Then the static characteristics and dynamic characteristics are researched by simulation model and the characteristic curves are compared with experimental data for the verification. The results show that simulation curves and experiment curves are in good agreement, which can be tolerated in the engineering.

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