Water from abandoned mines as a heat source: practical experiences of open- and closed-loop strategies, United Kingdom

Pilot heat pump systems have been installed at two former collieries in Yorkshire/Derbyshire, England, to extract heat from mine water. The installations represent three fundamental configurations of heat exchanger. At Caphouse Colliery, mine water is pumped through a heat exchanger coupled to a heat pump and then discharged to waste (an open-loop heat exchange system). The system performs with high thermal efficiency, but the drawbacks are: (1) it can only be operated when mine water is being actively pumped from the colliery shaft for the purposes of regional water-level management, and (2) the fact that the water is partially oxygenated means that iron oxyhydroxide precipitation occurs, necessitating regular removal of filters for cleaning. At Markham Colliery, near Bolsover, a small amount of mine water is pumped from depth in a flooded shaft, circulated through a heat exchanger coupled to a heat pump and then returned to the same mine shaft at a slightly different depth (a standing column arrangement). This system’s fundamental thermal efficiency is negatively impacted by the electrical power required to run the shaft submersible pump, but clogging issues are not significant. In the third system, at Caphouse, a heat exchanger is submerged in a mine water treatment pond (a closed-loop system). This can be run at any time, irrespective of mine pumping regime, and being a closed-loop system, is not susceptible to clogging issues

Environmental Selenium Research: From Microscopic Processes to Global Understanding

Selenium is a natural trace element that is of fundamental importance to human health. The extreme geographical variation in selenium concentrations in soils and food crops has resulted in significant health problems related to deficient or excess levels of selenium in the environment. To deal with these kinds of problems in the future it is essential to get a better understanding of the processes that control the global distribution of selenium. The recent development of analytical techniques and methods enables accurate selenium measurements of environmental concentrations, which will lead to a better understanding of biogeochemical processes. This improved understanding may enable us to predict the distribution of selenium in areas where this is currently unknown. These predictions are essential to prevent future Se health hazards in a world that is increasingly affected by human activities

Plasmodium falciparum: sensitivity in vivo to chloroquine, pyrimethamine/sulfadoxine and mefloquine in western Myanmar.

In Rakhine State, on the western border of Myanmar, the efficacy of chloroquine (CQ) and pyrimethamine/ sulfadoxine (PS), the current treatments for uncomplicated Plasmodium falciparum malaria in this area, was evaluated in an open comparative study of 289 patients, stratified prospectively into 3 age groups. Chloroquine treatment was associated with more rapid clinical recovery (P = 0.03), but the overall cure rates were worse than for PS treatment; failure to clear parasitaemia or recrudescence within 14 d occurred in 72% (102/141) of cases treated with CQ compared to 47% (69/148) of those who received PS (P < 0.0001, adjusted for age). Failure rates at day 28 increased to 82% (116/141) in the CQ group and 67% (99/148) in the PS group (P = 0.003). The risk of treatment failure was significantly higher in children under 15 years old than in adults for both CQ (relative risk [RR] = 2.6; 95% confidence interval [95% CI] 1.3-5.2) and PS (RR = 2.2; 95% CI 1.4-3.3). Mefloquine (15 mg base/kg) proved to be highly effective as a treatment for CQ and PS resistant P. falciparum; only 2 of 75 patients (3%) had early treatment failures (< or = day 7), and the overall failure rate by day 42 was 7%. There is a very high level of chloroquine and PS resistance in P.falciparum on the western border of Myanmar, but mefloquine was effective in the area

In-situ X-ray fluorescence to investigate iodide diffusion in opalinus clay: Demonstration of a novel experimental approach

During the last two decades, the Mont Terri rock laboratory has hosted an extensive experimental research campaign focusing on improving our understanding of radionuclide transport within Opalinus Clay. The latest diffusion experiment, the Diffusion and Retention experiment B (DR-B) has been designed based on an entirely different concept compared to all predecessor experiments. With its novel exper- imental methodology, which uses in-situ X-ray fluorescence (XRF) to monitor the progress of an iodide plume within the Opalinus Clay, this experiment enables large-scale and long-term data acquisition and provides an alternative method for the validation of previously acquired radionuclide transport parameters. After briefly presenting conventional experimental methodologies used for field diffusion experiments and highlighting their limitations, this paper will focus on the pioneer experimental methodology developed for the DR-B experiment and give a preview of the results it has delivered thus far

High-speed 1550 nm VCSEL data transmission link employing 25 Gbaud 4-PAM modulation and Hard Decision Forward Error Correction

Current short-range optical interconnects capacity is moving from 100 Gb/s to 400 Gb/s and beyond. Directly modulation of several laser sources is used to minimize bandwidth limitations of current optical and electrical components. Either this total capacity is provided by wavelengthdivision- multiplexing or parallel optics, it is important to investigate on the ultimate transmission capabilities of each laser source to facilitate current capacity standards and allow for future demands. High-speed 4-level pulse amplitude modulation at 25 Gbaud of a 1.5 #x00EC;m VCSEL is presented in this paper. The 20 GHz 3 dBbandwidth laser is, at the time of submission, the largest bandwidth of a 1.5 #x00EC;m VCSEL ever reported. Forward error correction (FEC) is implemented to achieve transmission over 100 m virtually error-free after FEC decoding. Linerate of 100 Gb/s is achieved by emulation polarization multiplexing using 50 Gb/s signal obtained from a single VCSEL