نتایج جستجو برای: mines
تعداد نتایج: 7308 فیلتر نتایج به سال:
We analyze R&D competition and cooperation between rms involved in the development of a technology standard. Our model captures the two counterweighting types of incentives these rms are subject to: free-riding due to the public good nature of the standard, and patent races in order to derive royalties from essential patents. As a consequence, R&D may be excessive or insu¢ cient as compared t...
Fatal accidents associated with underground coal mines require the implementation of high-level gas monitoring and miner’s localization approaches to promote underground safety and health. This study introduces a real-time monitoring, event-reporting and early-warning platform, based on cluster analysis for outlier detection, spatiotemporal statistical analysis, and an RSS range-based weighted ...
The purpose of this article is to develop knowledge and learning on the best way to automate organisational activities in deep mines that could lead to the creation of harmony between the human, technical and the social system, towards increased productivity. The findings showed that though the introduction of high-level technological tools in the work environment disrupted the social relations...
In 1948 roof falls were the number one killer of coal miners in America. While the Bureau of Mines had been formed in 1910 to improve coalmine safety, it had largely focused on explosions, for which technological solutions appeared to exist. Roof falls, by contrast, were not amenable to a technical fix. Beginning in 1948, however, the Bureau discovered roof bolting, which it promoted as a safer...
Formal tests over the last decade indicate that American soldiers using the AN/PSS-12 handheld mine detector and Army-approved techniques consistently find less than 20 percent of low-metal mines. 1,2,3,4 Too often this poor performance is rationalized by assuming that the detector itself is just not capable of detecting low-metal mines. Yet, at the same time, professional, commercial, civilian...
In some instances, extensive room-and-pillar workings can collapse with little warning and pose a serious risk to underground miners. Traditional strength-based pillar design methods applicable to coal or hard-rock mines use a factor of safety defined as pillar strength divided by pillar stress. Factor of stability, defined as local mine stiffness divided by post-failure pillar stiffness, may o...
Shanxi province in northern China has one of the highest reported prevalence rates of neural tube defects (NTDs) in the world. The current study selected Heshun, the county with the highest rate of NTDs in Shanxi, as a study area and tested whether residence in a coal mining area was a contributing factor. A NTD cluster was detected in an area within 6 km of the coal mines for almost every year...
In this review I evaluate the contribution of Spanish-American silver mines during the period 1570-1820 (a Spanish colonial period of 250 years) to the present high mercury concentrations in the global environment. The evaluation is based upon the following bibliographic information: (1) total amount of mercury consumed in Spanish-American silver mines between 1570 and 1820; (2) percentage of t...
OBJECTIVE The aim of this study was to determine the association between urinary cadmium (U-cd) concentration and diabetes in middle-aged Korean residents of abandoned mines using the first Health Effect Surveillance for Residents in Abandoned Metal mines (HESRAM). METHODS This study was cross-sectional study conducted on 719 residents between 40-70 years in 38 abandoned metal mines in Korea....
A brief description is given of the study of West Bohemian uranium miners, and recent and ongoing efforts to improve the quality of the data are summarized. Three recent analyses of the data from the cohort have led to rather different estimates of the excess relative risk of mortality from lung cancer per working-level month. The reasons for these different estimates are described, and it is c...
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید