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.     

Solar heating and night radiation cooling by a Roof Radiation Trap

The paper describes a new system, the Roof Radiation Trap, which utilizes solar energy for heating of buildings in winter and nocturnal radiation for cooling in summer. The radiation trap consists of fixed insulating layer separated from the flat roof and glazing, protected by hinged insulating panel, in the southern gap between the roof and the fixed insulation. This fixed insulating layer is covered by corrugated metal sheets, painted white, which serve as nocturnal radiators in summer.The radiation trap is integrated with the building, thermally as well as architecturally. In winter the sun energy penetrates through the glazing and is absorbed directly in the roof, which serves as a combined collector, storage for one night and heat distribution system.The hot air in the space between the flat roof and the fixed insulation is blown into a thermal storage of gravel, under the floor or inside the building. The stored heat is “recovered” by forced convection during cloudy days.In summer the penetration of solar radiation during daytime is prevented by the hinged insulating panel. At night the painted external metal layer is cooled by outgoing radiation and the air under the corrugations is blown into the space of the radiation trap and cools the roof, which, in turn, serves as a heat sink during the next day. Nocturnal evaporative cooling can supplement the radiant cooling.     

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...     

Diagnostics of Multioperation Processes Using Basic Cells of Digital Homogeneous Structures

Russian Electrical Engineering - The cells of homogeneous digital structures designed for multioperation process diagnostics are considered in the form of graphic models. Digital circuits and...     

Operational management of trunk main discolouration risk

Despite significant on-going investment, water companies continue to receive an unacceptable number of discolouration related customer contacts. In this paper, data from intensive distribution system turbidity monitoring and cluster analysis of discolouration customer contacts indicate that a significant proportion of these contacts are due to material mobilising from the trunk main system, and operational flow increases are shown to have a higher discolouration risk than burst incidents. A trunk main discolouration incident highlighting this risk is discussed, demonstrating the need for pro-active trunk main risk assessments. To identify the source of the material event flow rates were modelled using the PODDS (prediction of discolouration in distribution systems) discolouration model. Best practice pro-active management is demonstrated in a case study where the PODDS model is used to implement managed incremental flow changes on a main with known discolouration risk with no discolouration impact to customers and significant cost savings.     

Fitting interrelated datasets: metabolite diffusion and general lineshapes

Objective

Simultaneous modeling of true 2-D spectroscopy data, or more generally, interrelated spectral datasets has been described previously and is useful for quantitative magnetic resonance spectroscopy applications. In this study, a combined method of reference-lineshape enhanced model fitting and two-dimensional prior-knowledge fitting for the case of diffusion weighted MR spectroscopy is presented.

Materials and methods

Time-dependent field distortions determined from a water reference are applied to the spectral bases used in linear-combination modeling of interrelated spectra. This was implemented together with a simultaneous spectral and diffusion model fitting in the previously described Fitting Tool for Arrays of Interrelated Datasets (FiTAID), where prior knowledge conditions and restraints can be enforced in two dimensions.

Results

The benefit in terms of increased accuracy and precision of parameters is illustrated with examples from Monte Carlo simulations, in vitro and in vivo human brain scans for one- and two-dimensional datasets from 2-D separation, inversion recovery and diffusion-weighted spectroscopy (DWS). For DWS, it was found that acquisitions could be substantially shortened.

Conclusion

It is shown that inclusion of a measured lineshape into modeling of interrelated MR spectra is beneficial and can be combined also with simultaneous spectral and diffusion modeling.

     

Development of method to improve efficiency of residual current device under 1000 V on excavators of mining enterprises

This article presents the results of experimental studies on a coal mine. According to the results, the current of single phase-to-earth fault in the network under 1000 V has a value less than the current of the residual current device set point. This article presents a method aimed to improving the efficiency of the residual current device used on excavators and drill-rings at mining enterprises. Indeed, the method developed to improve the efficiency of residual current devices under 1000 V is based on setting up a direct current into three-phase mains with a fixed set-point of protection against any phase-to-ground insulation damage, where electric equipment is switched off due to increases of capacitance between a conductor and earth when live-line bare-hand touching of electric equipment occurs.     

Intensification of nonlinearity by dispersed events in media with structure and generation of various dominant frequencies in P- and S-waves

A model of a continuum with a structure described by infinite order equations of motion is proposed. In case that a wave is very long as compared with the size of the structure, equations are reduced to the fourth-order equations. A closed equation of motion, including nonlinear, dispersed and wave members, is derived. It is shown that solutions in the form of soliton waves exist only in media where wave velocity grows with pressure. In the media, where soliton waves do not exist, quasi-stationary solutions with multiple frequencies prevail. It is found that the nonlinear effect of multiple frequencies is unexpectedly high even for small deformation as dispersion violently intensifies nonlinear events. Moreover, in the domain of small deformation, there exist solutions for longitudinal and transversal waves with the same length and different frequencies. The solutions for the same length waves with different frequencies most often occur in seismology and seismic explorations.