Development of the properties of adaptability of the support sections of treatment complexes to variable mining and geological conditions

2021 ◽  
Vol 326 ◽  
pp. 00024
Author(s):  
Vasilisa Teremetskaya ◽  
Viktor Gabov
Keyword(s):  
Coal Mining ◽  
High Performance ◽  
Operating Conditions ◽  
Underground Coal Mining ◽  
Coal Seams ◽  
Functional Capabilities ◽  
Geological Conditions ◽  
Wide Range ◽  
Favorable Conditions ◽  
Working Out

In modern conditions, intensive underground coal mining is provided, as a rule by working out the dredging sections of coal seams with long cleaning faces using high-performance mechanized complexes. They consist of a dredging machine, a conveyor and a set of sections of mobile mechanized support (SMS). SMS, supporting the roof, controlling the mountain pressure (MP) and protecting the bottom-hole space, provide conditions in complex mechanized treatment faces (CMTF) for efficient and safe coal mining. However, the potential capabilities of modern complexes significantly exceed the values of efficiency indicators achieved when using them in operating conditions. One of the reasons for this situation is the insufficient adaptability of the SMS to the mining and geological conditions (MGC) changing in a wide range as the excavation sites are worked out. Therefore, at present, studies of the possibility of developing the properties of adaptivity (kinematic, power, contact, technological) of the SMS to the MGC variables are relevant. Their results will contribute to the expansion of the functional capabilities of the SMS to maintain favorable conditions in complex mechanized treatment faces for the effective operation of the mechanized treatment complex (MTC) in variable mining and geological conditions.

scholarly journals The evolution of thick coal seams mining methods in China

2020 ◽  
Vol 192 ◽  
pp. 01023
Author(s):  
Qiao Jianyong ◽  
Wang Zhiqiang ◽  
Zhao Jingli
Keyword(s):  
Coal Mining ◽  
Spontaneous Combustion ◽  
Underground Coal Mining ◽  
Coal Seams ◽  
Recovery Coefficient ◽  
Increased Risk ◽  
Geological Conditions ◽  
Mechanized Method ◽  
Full Capacity ◽  
The Moment

The article is shown that the main methods used in China for coal mining from thick seams at the moment are two methods the Complex mechanized method of developing seams at their full capacity (used only in simple geological conditions and is an additional method for the following) and Complex mechanized mining method with coal production (which is used mainly, including in difficult conditions). Despite the fact that these methods have positively proven themselves over the years, their use has a number of significant drawbacks, including a low extraction rate, an increased risk of endogenous combustion and rock burst, and others. Currently, a promising way is a development method with a diagonal (cross-shaped) arrangement of drifts, which helps to eliminate many of the shortcomings of previous methods, including a low recovery coefficient, the risk of spontaneous combustion, the need to support the drift and others. It is expected that this method will be widely used for underground coal mining in deep mines in China with difficult mining and geological conditions.

scholarly journals Methane Content Estimation in DuongHuy Coal Mine

2018 ◽  
Vol 35 ◽  
pp. 01005 ◽  
Author(s):  
Van Thinh Nguyen ◽  
Waldemar Mijał ◽  
Vu Chi Dang ◽  
Thi Tuyet Mai Nguyen
Keyword(s):  
Experimental Data ◽  
Coal Mining ◽  
Coal Mine ◽  
Coal Mines ◽  
Methane Content ◽  
Underground Coal Mining ◽  
Coal Seams ◽  
Underground Coal Mine ◽  
Different Depths ◽  
Quang Ninh

Methane hazard has always been considered for underground coal mining as it can lead to methane explosion. In Quang Ninh province, several coal mines such as Mạo Khe coal mine, Khe Cham coal mine, especially Duong Huy mine that have high methane content. Experimental data to examine contents of methane bearing coal seams at different depths are not similar in Duong coal mine. In order to ensure safety, this report has been undertaken to determine a pattern of changing methane contents of coal seams at different exploitation depths in Duong Huy underground coal mine.

scholarly journals Design and Evaluation of LYSO/SiPM LIGHTENING PET Detector with DTI Sampling Method

Sensors ◽  
2020 ◽  
Vol 20 (20) ◽  
pp. 5820
Author(s):  
Zhenzhou Deng ◽  
Yushan Deng ◽  
Guandong Chen
Keyword(s):  
High Performance ◽  
Sampling Method ◽  
Average Energy ◽  
High Sensitivity ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Time Interval ◽  
Silicon Photomultiplier ◽  
Experimental Conditions ◽  
Wide Range

Positron emission tomography (PET) has a wide range of applications in the treatment and prevention of major diseases owing to its high sensitivity and excellent resolution. However, there is still much room for optimization in the readout circuit and fast pulse sampling to further improve the performance of the PET scanner. In this work, a LIGHTENING® PET detector using a 13 × 13 lutetium-yttrium oxyorthosilicate (LYSO) crystal array read out by a 6 × 6 silicon photomultiplier (SiPM) array was developed. A novel sampling method, referred to as the dual time interval (DTI) method, is therefore proposed to realize digital acquisition of fast scintillation pulse. A semi-cut light guide was designed, which greatly improves the resolution of the edge region of the crystal array. The obtained flood histogram shown that all the 13 × 13 crystal pixels can be clearly discriminated. The optimum operating conditions for the detector were obtained by comparing the flood histogram quality under different experimental conditions. An average energy resolution (FWHM) of 14.3% and coincidence timing resolution (FWHM) of 972 ps were measured. The experimental results demonstrated that the LIGHTENING® PET detector achieves extremely high resolution which is suitable for the development of a high performance time-of-flight PET scanner.

Parameter Identification of LuGre Friction Model: Experimental Set-up Design and Measurement

2015 ◽  
Author(s):  
Yun-Hsiang Sun ◽  
Tao Chen ◽  
Cyrus Shafai
Keyword(s):  
High Performance ◽  
Controller Design ◽  
Measurement Procedure ◽  
Friction Model ◽  
Operating Conditions ◽  
Dynamic Friction ◽  
Friction Modeling ◽  
Friction Behavior ◽  
Wide Range ◽  
Set Up

This work proposes a simple but general experimental approach including the rig design and measurement procedure to carry out a wide range of experiments required for identifying parameters for LuGre dynamic friction model. The design choice is based on accuracy of the estimated friction and flexibility in terms of changing contact conditions. The experimental results allow a complete LuGre model, which facilitates, but not limited to, other advanced friction modeling and high performance controller design if needed. In addition, several well-known dynamic friction features (varying break-away force, friction lag and presliding) are successfully demonstrated by our rig, which indicates the adequacy of our approach for capturing highly sophisticated and dynamic friction behavior over a wide range of operating conditions. The proposed set-up and the produced experimental data are believed to greatly facilitate the development of advanced friction compensation and modeling in friction affected mechanisms.

Low-Power On-The-Fly Reconfigurable Iterative MIMO Detection and LDPC Decoding Design

2014 ◽  
Vol 496-500 ◽  
pp. 1825-1829 ◽  
Author(s):  
Ehsan Rohani ◽  
Jing Wei Xu ◽  
Gwan Choi ◽  
Mi Lu
Keyword(s):  
Low Power ◽  
High Performance ◽  
Signal To Noise Ratio ◽  
Wireless Systems ◽  
Operating Conditions ◽  
Mimo Detection ◽  
Ldpc Decoding ◽  
Wide Range ◽  
Multiple Input

Manufacturing and operation of wireless systems require a practical solution for achieving low-power and high-performance when using advance communication apparatus such as that using multiple-input and multiple-output (MIMO). Often algorithm solutions achieve very high performance but over only in a narrow range of operating parameters. This paper presents a hardware design of MIMO detection that allows real-time switching between various algorithms and detection effort to achieve high performance over the wide-range of signal to noise ratio (SNR) found in realistic operating conditions. We illustrate a design with over 80% reduction in detection power that satisfies the required quality of service (QoS) in SNRs (Eb/No) as low as 8.7 dB.

scholarly journals Program for determination of zones of gold concentration on sluices of washing devices

2021 ◽  
Vol 895 (1) ◽  
pp. 012002
Author(s):  
V S Alekseev ◽  
R S Seryi
Keyword(s):  
High Performance ◽  
Two Phase Flow ◽  
Experimental Studies ◽  
Operating Conditions ◽  
Phase Flow ◽  
Technological Parameters ◽  
Two Phase ◽  
Alluvial Gold ◽  
Wide Range ◽  
Host Rocks

Abstract Currently sluice washing devices are the most common in alluvial gold mining. Their use provides a sufficiently high performance, relatively low power consumption, and acceptable recovery of valuable components. The theoretical provisions of traditional hydraulics make it possible to determine all the main parameters of the movement of particles of rocks and gold in the pulp, however, in real operating conditions of the sluice box, their actual values will differ greatly from the calculated ones, especially if there are solid fractions in the pulp with a particle size of more than 20 mm. This is explained by significant fluctuations in the values of the surface, average and bottom velocities of the two-phase flow, vertical pulsation velocity in conditions of constrained movement of the different fractional composition of rocks. The article presents the results of experimental studies to identify the dependence of the distance traveled by an individual gold particle and host rocks in a two-phase flow through a sluice, the bottom of which is lined with trapping coatings, on the design and technological parameters of the flushing device. The mathematical model for determining this distance formed the basis of the Gold Enriching program. The program allows, in a wide range of initial data, to determine the zones of concentration of gold of a certain size at the sluice boxes.

Investigation on the Degree of Reaction in Twin Scroll Radial Turbines at Different Operating Conditions for Turbocharging Applications

2019 ◽  
Author(s):  
Carlo Cravero ◽  
Davide De Domenico ◽  
Andrea Ottonello
Keyword(s):  
High Performance ◽  
Mean Value ◽  
Operating Conditions ◽  
Axial Thrust ◽  
Degree Of Reaction ◽  
Radial Turbine ◽  
Wide Range ◽  
Partial Admission ◽  
Rotor Losses ◽  
Radial Turbines

Abstract Frequently in turbocharging radial turbine studies, some assumptions have to be done in order to make 1D matching calculations as easy as possible and to develop simulation approaches that can be useful for different purposes, like axial thrust prediction. One of these assumptions concerns the degree of reaction, which is often considered constant and equal to the value 0.5. In standard radial turbines design the velocity triangles are set by the target to keep a mean degree of reaction of 50%, in order to obtain low rotor losses and to minimize the exit swirl to get lower losses in the exhaust diffuser. From the experience gained on radial turbines operating in a wide range of conditions, it is evident that: the degree of reaction presents large variations along a given isospeed (especially at low rotational speed) and the mean value is far from 0.5 (particularly true in high performance applications). In the present work a method for the representation of the degree of reaction for radial turbine is suggested. The approach has been developed onto a twin scroll radial turbine for turbocharging, considering a large dataset of operating conditions (at both equal and partial admission). The discussion and the method suggested are based on a rich database from experimental data and numerical simulations developed by the authors on the 3D configuration of the turbines under investigation.

Material Characterization of Rubber Vulcanizates under Dynamic Conditions Appropriate for Tire Modeling

1991 ◽  
Vol 19 (2) ◽  
pp. 79-99 ◽  
Author(s):  
D. G. Young
Keyword(s):  
Finite Element ◽  
High Performance ◽  
Fatigue Testing ◽  
Nonlinear Models ◽  
Pure Shear ◽  
Strain Range ◽  
Operating Conditions ◽  
Simple Extension ◽  
Strain Rates ◽  
Wide Range

Abstract Material property data used in finite element and other models for tire applications have often been obtained under static or low strain rate conditions at room temperature. In the latter case Williams-Landel-Ferry (WLF) shifts are assumed in order to relate the data to strain rates and temperatures typical of actual tire operation. However, such shifts may not always be appropriate for the highly loaded, diverse elastomer blends used in tires today unless one wishes to go to the trouble of generating the WLF constant for each compound. Data are presented to show that one can directly and easily obtain high quality stress or strain energy density results over wide ranges of strain rates, strain levels, and temperature using techniques developed for fatigue characterization. Thus, material properties can be obtained as a by-product of fatigue testing with little added work, or they can be obtained straightforwardly and quickly if fatigue testing is not required. These data are generated in a dynamic, pulsed loading mode which is especially relevant for those modeling applications which deal with the rolling tire. Results from a high performance tire tread, a sidewall, and an innerliner are presented to illustrate the wide range of compounds that can be accommodated. The primary mode of deformation employed is pure shear. Also, limited data from static simple extension and pulsed simple extension tests are shown for comparison. The pulsed pure shear and simple extension data, obtained over a wide strain range, are an excellent source of basic information on a given compound to fit empirical models, generate Mooney-Rivlin constant, or define material constants for more generalized nonlinear models such as Ogden, Peng, or Peng-Landel. The latter material models are now becoming available in commercial finite element codes to allow studies of tire deformations, rolling resistance, and failure properties under realistic operating conditions.

Combined Microstructure and Heat Conduction Modeling of Heterogeneous Interfaces and Materials

2013 ◽  
Vol 135 (6) ◽  
Author(s):  
Ishan Srivastava ◽  
Sridhar Sadasivam ◽  
Kyle C. Smith ◽  
Timothy S. Fisher
Keyword(s):  
Transport Properties ◽  
High Performance ◽  
Energy Transport ◽  
Heterogeneous Materials ◽  
Operating Conditions ◽  
High Fidelity ◽  
Energy Materials ◽  
Wide Range ◽  
Material State ◽  
Random Structures

Heterogeneous materials are becoming more common in a wide range of functional devices, particularly those involving energy transport, conversion, and storage. Often, heterogeneous materials are crucial to the performance and economic scalability of such devices. Heterogeneous materials with inherently random structures exhibit a strong sensitivity of energy transport properties to processing and operating conditions. Therefore, improved predictive modeling capabilities are needed that quantify the detailed microstructure of such materials based on various manufacturing processes and correlate them with transport properties. In this work, we integrate high fidelity microstructural and transport models, which can aid in the development of high performance energy materials. Heterogeneous materials are generally comprised of nanometric or larger length scale domains of different materials or different phases of the same material. State-of-the-art structural optimization models demonstrate the predictability of the microstructure for heterogeneous materials manufactured via powder compaction of variously shaped and sized particles. The ability of existing diffusion models to incorporate the essential multiscale features in random microstructures is assessed. Lastly, a comprehensive approach is presented for the combined modeling of a high fidelity microstructure and heat transport therein. Exemplary results are given that reinforce the importance of developing predictive models with rich stochastic output that connect microstructural information with physical transport properties.

scholarly journals Intensive underground mining technologies: Challenges and prospects for the coal mines in Russia

2021 ◽  
pp. 60-69
Keyword(s):  
Coal Mining ◽  
High Performance ◽  
Underground Mining ◽  
Strain Analysis ◽  
Environmental Indicators ◽  
Mining Equipment ◽  
Underground Coal Mining ◽  
Mining Operations ◽  
Mining Companies ◽  
Production Growth

The article presents the key features of underground coal mining that influence the development of mining technologies and mining equipment design. It covers the most important challenges faced by underground coal mining companies and discusses growth areas in mining technology that are aligned with the paradigm of sustainable development. Using the example of underground coal mining operations, it illustrates such concepts as the intelligent mine and the invisible mine, discussing how they can be brought to life. It also shows how underground coal mining companies can improve their productivity, OSH management, and environmental indicators to make their products competitive. As mining operations are becoming more intensive and the average depth of mining is growing, which is accompanied by an increase in both methane emissions and risks associated with rock mechanics processes, it is becoming vital to accurately predict how the rock mass will behave and, by applying stress-strain analysis, to identify hazardous zones and their boundaries. The article discusses several mine layouts and how their parameters are adjusted to ensure intensive mining. Among the factors that hinder growth in coal production, it highlights the underutilisation of high-performance mining equipment. It also contains a list of key principles aimed at fostering production growth in the underground coal mining sector and improving its competitiveness.

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