نتایج جستجو برای: underground economy
تعداد نتایج: 107969 فیلتر نتایج به سال:
Wireless Underground Sensor Networks (WUSN) constitute one of the promising application areas of the recently developed wireless sensor networking techniques. The main difference between WUSN and the terrestrial wireless sensor networks is the communication medium. The propagation characteristics of electromagnetic (EM) waves in soil and the significant differences between propagation in air pr...
Due to the high attenuation of radio frequency (RF) signals in underground mines and the statutory power restriction of communication gadgets especially for coal mines, the wireless communication systems have restricted applications in the underground mines. The paper discusses different radio frequency communication techniques being employed for Indian underground mines. Experiments were condu...
Due to its unique sensitivity to hydrogen protons, magnetic resonance sounding (MRS) is the only geophysical method that directly detects water and can provide nondestructive information on subsurface aquifer properties. The relationship between the surface MRS signal and the location and characteristics of aquifers using large-coil (typically 50-150 m) sensors has been discussed based on forwa...
Many coal mine companies have established underground safety monitor and control systems. However, the safety management information can only be displayed on the 2D maps or as reports. In this paper, a new method that combines the VR technologies with underground mine safety monitoring technologies was explored. A desktop virtual reality program for underground coal mine, called VRLane, was dev...
This study examined the effect of underground water on reproductionand growth-related hormones in blue gourami males under non-reproductive and reproductive conditions. An increase in the percentage of males building nests under the highest percentage of underground water were compared to fish that maintained a lower percentage of underground water in the first two days. The % Gonado-somatic in...
Wireless underground sensor networks (WUSNs) constitute one of the promising application areas of the recently developed wireless sensor networking techniques. The main difference between WUSNs and the terrestrial wireless sensor networks is the communication medium. The propagation characteristics of electromagnetic (EM) waves in soil and the significant differences between propagation in air ...
Studies conducted on surface coal mining equipment have identified whole-body vibration as a significant hazard. Operators of underground mobile equipment, particularly shuttle cars and transport vehicles, are likely to be exposed to significant levels of whole-body vibration. To date, measuring whole-body vibration from underground mining mobile equipment has been difficult due to the strict g...
Respiratory symptoms, spirometry, and transfer factor were measured in 208 non-smoking Western Australian underground goldminers (mean age 32) to identify the presence of respiratory abnormalities resulting from underground work. These subjects were part of a larger group of 771 subjects attending for statutory periodic chest x ray examinations in the industry. They had worked underground for a...
Researchers have worked on routing issues for adhoc-networks, VANET’s, and Wireless Sensor Networks in a normal scenario; recently there has been a recent trend towards the study on underground wireless networks and proposals for design and development for Wireless Underground Sensor Networks. This paper highlights the concept of wireless underground sensor network in the coal mine environment,...
A complete methodology is employed to determine the transmission characteristics of low-voltage/broadband over power lines (LV/BPL) channels associated with underground power distribution networks, in the light of the multiconductor transmission line (MTL) theory. The established bottom-up approach, already used to treat overhead and underground MV/BPL transmission, is extended to analyze BPL t...
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