نتایج جستجو برای: zarand coal mine
تعداد نتایج: 51902 فیلتر نتایج به سال:
The German Rhineland is home to the world's largest opencast lignite coal mine and human-made hole e the Hambach mine. Over the last seven years, RWE, the mine operator, has faced an increase in militant resistance, culminating in the occupation of the Hambacher Forest and acts of civil disobedience and sabotage. The mine provides a European case study to examine the repressive techniques deplo...
The development of a sampling instrument for the assessment of an underground coal miner’s exposure to airborne respirable coal mine dust on a continuous and real-time basis has been long identified as essential for timely initiation of control actions. A respirable dust dosimeter (RDD) which operates on the principle of increasing pressure across a filter media with increasing dust mass on the...
To overcome the frequency-selective fading of ultra wide band (UWB) caused by the multi-path propagation in complicated environment of coal mines, an underground wireless communication system of UWB based on multi-band orthogonal frequency division multiplexing (MB-OFDM) for coal mine is presented. Independent angle impulse response is used to build up revised channel model for underground tunn...
— An average Transmitted-Reference (TR) receiver scheme based on orthogonal codes is proposed for improving the bit error rate (BER) performance and the transmitting rate of Ultra-wideband (UWB) TR receiver systems in coal mine. Orthogonal codes are used for modulating the reference pulses and the data pulses in each frame of every bit. Since the orthogonality of the two codes, the inter-pulse...
In view of the coal dust concentration measurement elements, the measurement pollution environment will reduce the measurement accuracy. The paper proposes a soft measurement method of mine dust concentration based on the K-RBF neural network theory. It takes the electrostatic signal as the measurement signal and extracts the short-term energy, RMS and rectification value of the electrostatic s...
The RFID-based positioning equipment, which is widely used in mine operation such as coal mine, has the advantages of low cost and maturity. It can locate human effectively so that it could improve the production safety situation and provide guarantee for disaster prevention and relief. However, the traditional RFID technology has the drawbacks of small monitoring range and no orientation which...
The influence of the coal mine geographical environment on the electromagnetic transmission might result in the difficulty of wireless positioning under the mine. Concerning that the influence of the underground working face on the wireless signal attenuation is mainly reflected on the path attenuated electricity and based on the underground geographical differences, two corresponding electroma...
The Federal Mine Safety and Health Act of 1977 consolidated all federal health and safety regulations of the mining industry-coal as well as noncoal mining-under a single mandate administered by the Mine Safety and Health Administration (MSHA). Today, the agency is striving to reduce the environmental health risks associated with mining.
The coal and gas outburst is one of complex geological disasters and its prediction is influenced by a multiple of factors, such as coal gas, ground stress, physical and mechanical properties, and complex non-linear system, which cause the low prediction accuracy. It is a favorable scheme to use the nonlinear BP neural network for the prediction algorithm design. But, the traditional BP neural ...
In order to rapidly identify the source of water inrush in coal mine, and provide the theoretical basis for mine water damage prevention and control, fuzzy comprehensive evaluation model was established. The F statistics of water samples was normalized as the weight of fuzzy comprehensive evaluation for determining the source of water inrush in coal mine. The determination result of F statistic...
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