نتایج جستجو برای: underground cavity

تعداد نتایج: 93377  

2013
Gad Degani Gal Levy

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...

Journal: :Physical Communication 2010
Mehmet C. Vuran Ian F. Akyildiz

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 ...

2016
D. Lynas

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...

Journal: :British journal of industrial medicine 1992
A W Musk I L Rouse B Rivera N H de Klerk J C McNulty

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...

2012
Hariom Agrawal

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,...

2012
A. G. Lazaropoulos

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...

Journal: :JCP 2013
Xiaoqing Yu Pute Wu Ning Wang Wenting Han Zenglin Zhang

Wireless underground sensor networks (WUSN) are a natural extension of the wireless sensor networks (WSN) phenomenon to the underground environment. In this work, experimental measurements are presented at the frequency of 433 MHz, which show a good agreement with the theoretical studies. Experiments are run to examine the received signal strength and the packet error rate for aboveground-to-un...

2008
J. Larsson

During the last decade, mining companies and mobile equipment manufacturers have pursued improved efficiency, productivity, and safety in underground mining operations by automating some of the functions of underground vehicles. This paper describes the implementation and successful field testing of a new infrastructureless guidance system for autonomous tramming of centre-articulated undergrou...

2014
Akiteru Takamori Akito Araya Wataru Morii Souichi Telada Takashi Uchiyama Masatake Ohashi

We have developed and built a highly accurate laser strainmeter for geophysical observations. It features the precise length measurement of a 100-m optical cavity with reference to a stable quantum standard. Unlike conventional laser strainmeters based on simple Michelson interferometers that require uninterrupted fringe counting to track the evolution of ground deformations, this instrument is...

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