Radon and 'King Solomon's Miners': Faynan Orefield, Jordanian Desert

Concentrations of 222Rn were measured in ancient copper mines which exploited the Faynan Orefield in the South-Western Jordanian Desert. The concentrations of radon gas detected indicate that the ancient metal workers would have been exposed to a significant health risk and indicate that any future attempt to exploit the copper ores must deal with the hazard identified. Seasonal variations in radon concentrations are noted and these are linked to the ventilation of the mines. These modern data are used to explore the differential exposure to radon and the health of ancient mining communities.     

Arsenic and heavy metals in soils associated with regional geochemical anomalies in South-West England

Regional geochemical maps have shown extensive anomalies of arsenic, copper and other heavy metals in those parts of South-West England associated with mineralised zones around the granite intrusion. Studies in the vicinity of the River Tamar and of the metamorphic aureole around Dartmoor have confirmed significantly higher concentrations of arsenic and heavy metals in soils contaminated by mining, smelting and mineralisation compared with those from nearby control areas. Arsenic and copper show the greatest degree of enhancement ranging up to 900 ppm As and 2000 ppm Cu in both alluvial and upland topsoils within the Tamar area. Preliminary analyses indicate that the trace metal content of pasture herbage-reflects in part the degree of soil contamination. Maximum concentrations of 35 ppm As and 22 ppm Cu in autumn sampled herbage were found at contaminated sites compared with mean values of less than 0.5 ppm As and 8 ppm Cu in control areas. Geochemical reconnaissance surveys based on stream sediment sampling provide a useful indication of areas wherein widescale soil contamination may occur.     

Analysis of Methods for Parallel Operation of Frequency Converters

Consideration is given to methods for the parallel operation of frequency converters by applying the active load division. The simulation model of the converter is presented. It consists of three parallel independent modules. A new principle of constructing individual modules of a frequency converter and the principle of their communication interface exhibiting resistance to destabilizing effects and allowing safe operation under nominal conditions even with a 5- to 10% range in time and amplitude values of pilot signals are developed.     

Electromagnetic Effect of an Alternating Current Traction Power Supply System with a High-Voltage Power Cord on Electrical Installations and Networks of Nontraction Consumers

Russian Electrical Engineering - In this paper, we ground a method for calculating switching overvoltages including the discharge of lightning currents into the contact network and into a...     

The Effect of Energy-Supply and Performance Indicators on the Performance of Traction-Resource Management Centers

Russian Electrical Engineering - This paper presents the results of a study of the effect of the characteristics of the traction power-supply system on the indicator of the energy supply of...     

Finite element analysis of optimized brace angle for the diagrid structural system

International Journal of Steel Structures - The Diagrid structural system is considered to be the best structural system for constructing free form structures, but it is also a very effective...