scholarly journals Methods of Reducing the Front Performance Flame at the Underground Mines Works

2018 ◽  
Vol 34 (6) ◽  
pp. 3037-3043 ◽  
Author(s):  
M. I. Tulepov ◽  
Z. A. Mansurov ◽  
Yu. V. Kazakov ◽  
F. Yu. Abdrakova ◽  
Z. L. Sultanova ◽  
...  
Keyword(s):  
Ammonium Nitrate ◽  
Flame Front ◽  
High Energy ◽  
Underground Mines ◽  
Propagation Path ◽  
Confined Space ◽  
Barrier Thickness ◽  
Smokeless Powder ◽  
Penetration Ability ◽  
Pyrotechnic Composition

The aim of the study was to develop methods to reduce the penetration ability of the flame front and red-hot striking elements that propagate in the confined space of mines. In the article is considered a method for localizing explosions of a methane-dust mixture in coal mines, by creating an aqueous barrier (increased density) in the propagation path of the flame front and incandescent particles, using a high-energy pyrotechnic composition based on nanoaluminum. The optimal pyrotechnic composition contents of ammonium nitrate - 50%, smokeless powder - 45%, magnesium - 3% and nanoaluminum - 2%. This composition punched the target to a depth of 6.5 mm with a barrier thickness of 50 mm. Water cannon with a nozzle with a diameter of 80mm, allows to localize the spread of the flame front.

scholarly journals STUDY OF THERMAL DECOMPOSITION PRODUCTS OF NITROGEN-PHOSPHORUS-POTASSIUM FERTILIZERS BASED ON AMMONIUM NITRATE BY X-RAY DIFFRACTUON

2017 ◽  
Vol 61 (1) ◽  
pp. 72
Author(s):  
Konstantin G. Gorbovskiy ◽  
Alena S. Ryzhova ◽  
Andrey M. Norov ◽  
Denis A. Pagaleshkin ◽  
Valentina N. Kalinina ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Thermal Decomposition ◽  
Phosphoric Acid ◽  
Ammonium Nitrate ◽  
Confined Space ◽  
Decomposition Products ◽  
X Ray ◽  
Thermal Decomposition Products ◽  
Nitrogen Phosphorus ◽  
Thermal Stability Of

Complex mineral ammonium nitrate-based fertilizers are complex multicomponent salt systems possessing low thermal stability and prone to self-sustaining decomposition. This leads to the need to increase the requirements for fire and explosion safety in their manufacture, storage and transportation, caused by the fact that ammonium nitrate is a solid oxidant able to support a combustion, and its heating in confined space can lead to detonation. Components that make up such fertilizers can both reduce (phosphates and ammonium sulfate) and accelerate (chlorine compounds) decomposition of ammonium nitrate. Thus, the thermal stability of fertilizers based on ammonium nitrate largely depends on the ratio of the components that make up its composition or formed as a result of the chemical reaction. The simplest way to reduce the content of ammonium nitrate and increase the thermal stability of fertilizer without changing the content of essential nutrients is to increase the degree of phosphoric acid ammoniation. In this paper, the phase composition change of grade 22:11:11 nitrogen-phosphorus-potassium fertilizer obtained with different ammoniation degree in the process of thermal decomposition was studied by X-ray phase analysis. To obtain this fertilizer, wet-process phosphoric acid obtained sulfuric acid attack of the Khibin apatite concentrate by a hemihydrate method is used. It is shown that an increase in the ammoniation degree has a significant effect on the exothermic decomposition of ammonium nitrate and the amount of material that is released into the gas phase. The phases formed at each stage of the decomposition are determined.Forcitation:Gorbovskiy K.G., Ryzhova A.S., Norov A.M., Pagaleshkin D.A., Kalinina V.N., Mikhaylichenko A.I. Study of thermal decomposition products of nitrogen-phosphorus-potassium fertilizers based on ammonium nitrate by X-ray diffractuon. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 1. P. 72-77

scholarly journals Optimization of the Cutting Process Parameters to Ensure High Efficiency of Drilling Tunnels and Use the Technical Potential of the Boom-Type Roadheader

Energies ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 6597
Author(s):  
Piotr Cheluszka
Keyword(s):  
Control System ◽  
Energy Consumption ◽  
Automatic Control ◽  
Automatic Control System ◽  
Process Parameters ◽  
High Efficiency ◽  
Rock Cutting ◽  
High Energy ◽  
Cutting Process ◽  
Underground Mines

This paper deals with the automation of the rock cutting process with roadheaders used widely in civil engineering for drilling roadways in underground mines and tunnels. Although there has been intensive technical development, roadheaders are still manually controlled. Manual control does not allow optimizing the values of the cutting process parameters, which often results in low mining efficiency, especially in the case of hard rocks, as well as high energy consumption and significant dynamic overloading of the roadheader. As part of theoretical and experimental research, an automatic control system was designed for the boom-type roadheader and an algorithm was developed for the optimal control of the cutting process parameters. Control criteria have been formulated, based on which the current values of the cutting process parameters are worked out using the information on the dynamic load state of the roadheader. The paper presents selected results of numerical tests conducted on roadheader dynamics, which simulated the automatic control system operation of the heading face cutting process of drilled roadway or tunnel. These tests were intended to analyze the behavior of the investigated object during simulated rock cutting in automatic mode. The results confirmed the possibility of a significant reduction in mining energy consumption.

THE BURNING RATE OF HIGH-ENERGY MATERIALS CONTAINING METAL FUELS BASED ON AL AND B

2020 ◽  
Author(s):  
A. Korotkikh ◽  
◽  
I. Sorokin ◽  
E. Selikhova ◽  
V. Arkhipov ◽  
...  
Keyword(s):  
Ammonium Nitrate ◽  
Specific Energy ◽  
High Energy ◽  
Solid Propellants ◽  
Amorphous Boron ◽  
Energy Materials ◽  
Energy Characteristics ◽  
High Energy Materials ◽  
Metal Borides ◽  
Active Fuel Binder

An effective method of increasing the energy characteristics of high-energy materials (HEMs) is the use of boron and metal borides powders, which have high values of specific energy released during oxidation and combustion. This study investigates powders of amorphous boron and aluminum borides, which are used in compositions of solid propellants based on ammonium perchlorate, ammonium nitrate, and active fuel-binder.

Modeling of supersonic crowdion clusters in FCC lattice: Effect of the interatomic potential

2021 ◽  
pp. 2050019
Author(s):  
Igor A. Shelepev ◽  
Ayrat M. Bayazitov ◽  
Elena A. Korznikova
Keyword(s):  
Interatomic Potential ◽  
High Energy ◽  
Propagation Path ◽  
Interatomic Potentials ◽  
Energy Localization ◽  
Many Body ◽  
Embedded Atom ◽  
Fcc Lattice ◽  
The Many ◽  
Body Potential

Among a wide variety of point defects, crowdions can be distinguished by their high energy of formation and relatively low migration barriers, which makes them an important agent of mass transfer in lattices subjected to severe plastic deformation, irradiation, etc. It was previously shown that complexes and clusters of crowdions are even more mobile than single interstitials, which opened new mechanisms for the transfer of energy and mass in materials under intense external impacts. One of the most popular and convenient methods for analyzing crowdions is molecular dynamics, where the results can strongly depend on the interatomic potential used in the study. In this work, we compare the characteristics of a crowdion in an fcc lattice obtained using two different interatomic potentials — the pairwise Morse potential and the many-body potential for Al developed by the embedded atom method. It was found that the use of the many-body potential significantly affects the dynamics of crowdion propagation, including the features of atomic collisions, the evolution of energy localization and the propagation path.

scholarly journals Substorm correlated absorption on a 3200 km trans-auroral HF propagation path

1996 ◽  
Vol 14 (2) ◽  
pp. 182-190 ◽  
Author(s):  
S. E. Milan ◽  
T. B. Jones ◽  
M. Lester ◽  
E. M. Warrington ◽  
G. D. Reeves
Keyword(s):  
High Energy ◽  
Electron Precipitation ◽  
Propagation Path ◽  
Expansion Phase ◽  
Experimental Campaign ◽  
High Energy Electrons ◽  
Hf Propagation ◽  
Median Level ◽  
D Region ◽  
Asymmetric Behaviour

Abstract. A high-frequency transmitter located at Clyde River, NWT, Canada, and a receiver located near Boston, USA, provide a 3200 km trans-auroral, near-meridional propagation path over which the propagation characteristics have been measured. Out of the fourteen frequencies in the HF band sampled every hour for the duration of the experimental campaign (16 January–8 February 1989), the signal level measurements of 6.800 MHz transmissions were selected in order to determine the extent and occurrence of auroral absorption. The median level of auroral absorption along the path is found to increase with geomagnetic activity, quantified by the index Kp, with the increase being greater in the post-midnight sector than in the pre-midnight sector. This asymmetric behaviour is attributed to the precipitation of high energy electrons into the midnight and morning sector auroral D region. The measured diurnal variation in the median level of absorption is consistent with previous models describing the extent and magnitude of auroral absorption and electron precipitation. Individual substorms, identified from geosynchronous satellite data, are found to cause short-lived absorption events in the HF signal level of ~30 dB at 6.800 MHz. The occurrence of substorm correlated auroral absorption events is confined to the midnight and morning sectors, consistent with the location of the electron precipitation. The magnitude of absorption is related to the magnetotail stress during the substorm growth phase and the magnetotail relaxation during the substorm expansion phase onset. The absorption magnitude and the occurrence of substorms during the period of the campaign increase at times of high Kp , leading to an increase in median auroral absorption during disturbed periods.

scholarly journals Exergy Efficiency Promotion for the System of CO2 Hydrogenation to Methanol in Habitable Confined Space

2021 ◽  
Vol 9 ◽  
Author(s):  
Kai Xiong ◽  
Yong-Li Yin ◽  
Yong Cao ◽  
Xiao-Tian Liu
Keyword(s):  
Carbon Dioxide ◽  
Energy Consumption ◽  
Working Condition ◽  
Space Velocity ◽  
High Energy ◽  
Exergy Efficiency ◽  
Total System ◽  
Exergy Destruction ◽  
Confined Space ◽  
External Energy

Excess hydrogen and carbon dioxide will be produced during the operation of life support systems in the habitable confined space (HCS), and to eliminate the two excess gases by converting them into methanol is of great significance for maintenance of atmospheric balance and protection of crew’s life safety. Due to the limited energy supply ability within the HCS, it is important for the system of carbon dioxide hydrogenation to methanol (CDHM) to operate with high energy efficiency to reduce unnecessary external energy consumption and internal energy loss. In this paper, the exergy analysis method is adopted for exergy efficiency improvement. Specifically, a parametric study on the exergetic performance of the CDHM system is conducted based on the three key working condition parameters that have a huge impact on the reaction process and energy utilization quality, which is used to find the favorable working condition with low external energy consumption and exergy destruction per unit gas elimination and high exergy efficiency. Within the chosen three reaction parameters which are reaction pressure, temperature, and space velocity ranging from 5 to 8 MPa, from 483.15 to 543.15 K, and from 2,800 to 4000 h−1, respectively, the gas elimination of carbon dioxide and hydrogen increases by 13.3, 19.58, and 30.58%, respectively. Moreover, the input power, cold energy consumption, and exergy destruction per molar synthetic methanol all grow to some extent, leading to a 0.06% decline, a 0.46% promotion, and a 0.15% decrease, respectively, in the exergy efficiency. The results show that the high exergy efficiency can be realized with relatively low pressure, high temperature, and low space velocity in the working condition. Besides, the exergy destructions of each component in the CDHM system are also presented in this paper. The exergy destructions in the methanol synthesis reactor, heater, and heat exchanger hot end are found to be the three biggest, whose summation accounts for more than 90% of the total system exergy destruction. Thus, the exergy efficiency also can be improved by reducing the three biggest exergy destructions.

scholarly journals THE ANALYSIS OF SEISMIC LOAD CHARACTRESITIC OBSERVED IN THE LOWER SILESIAN COPPER BASIN

2020 ◽  
Vol 2 (2) ◽  
pp. 35-49 ◽  
Author(s):  
Krzysztof Fuławka ◽  
Lech Stolecki ◽  
Izabela Jaśkiewicz-Proć ◽  
Witold Pytel ◽  
Piotr Mertuszka
Keyword(s):  
Seismic Wave ◽  
Seismic Activity ◽  
Seismic Waves ◽  
Seismic Source ◽  
High Energy ◽  
Dominant Frequency ◽  
Underground Mines ◽  
Seismic Load ◽  
Mining Operations ◽  
Time Frequency

One of the major problems associated with the excavation of the copper deposits in underground mines in Poland is the relatively high level of seismic activity. Numerous high-energy tremors can negatively affect the stability of underground workings and can have a destructive impact on the infrastructure located at the surface as well. As predicted, the seismic activity increases along with the depth of mining operations. Therefore, to face these threats, a number of organizational and technical prevention methods have been applied in the mines. One of them is the assessment of the effect of additional dynamic loads on the structures behaviour with the use of numerical modelling. Recently there have been some possibilities of conducting dynamic analyses, i.e. using the finite element method that allows gathering information on the changes in stress conditions or deformation levels within the analysed object. Unfortunately, these kinds of calculations are usually performed after the occurrence of an unwanted event, so it is rather a post factum method. This is mainly due to the lack of information about the worst scenario of seismic wave distribution. At the same time, during the preliminary risk assessment, in most cases, only the maximum predicted value of seismic wave amplitudes is taken into consideration. Other dynamic parameters such as dominant frequency and duration of seismic wave are usually omitted. In this paper, the time-frequency characteristics of induced seismic waves observed within the Lower Silesian Copper Basin were analysed. Based on the high-energy seismic events database, dominant frequencies, amplitudes and tremor durations were determined. Then the correlation between each parameter, i.e. the energy of each tremor and their hypocentic distance from the seismic source and monitoring station were determined.

scholarly journals Зажигание борсодержащих высокоэнергетических материалов на основе окислителя и полимерного связующего

2021 ◽  
Vol 91 (6) ◽  
pp. 926
Author(s):  
А.Г. Коротких ◽  
И.В. Сорокин ◽  
К.В. Слюсарский ◽  
В.А. Архипов
Keyword(s):  
Ammonium Nitrate ◽  
Ammonium Perchlorate ◽  
Ignition Delay ◽  
Delay Time ◽  
Ignition Delay Time ◽  
Pure Aluminum ◽  
High Energy ◽  
Metal Powders ◽  
Energy Materials ◽  
Constant Rate

The use of aluminum borides is a promising direction in the development of modern fuel compositions and aircraft. The paper presents experimental data on the kinetics of oxidation of micro-sized powders of aluminum, amorphous boron, aluminum borides AlB2 and AlB12 in air when heated at a constant rate of 10 °C/min., as well as the results of laser ignition of high-energy materials based on ammonium perchlorate, ammonium nitrate, inert and active combustible binders containing these metal powders. It was found that the use of boron-based powders makes it possible to reduce the temperatures of the onset and intensive oxidation, and to increase their completeness of oxidation in comparison with pure aluminum. The obtained dependences of the ignition delay time on the heat flux density showed that AlB2 and AlB12 powders included in the HEM based on ammonium perchlorate, ammonium nitrate, and an active binder are the most effective metal fuels in terms of reducing the ignition delay time and the heat input.

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