Exposure levels to brominated compounds in seawater swimming pools treated with chlorine

Despite evidence of formation of brominated compounds in seawater swimming pools treated with chlorine, no data about exposure levels to these compounds have been reported. To address this issue, a survey has been carried out in four establishments (representing 8 pools) fed with seawater and devoted to relaxing and cure treatments (thalassotherapy centres located in Southeast of France). Carcinogenic and mutagenic brominated disinfection byproducts (trihalomethanes -THM- and halogenated acetic acids -HAA-) were quantified at varying levels, statistically related to organic loadings brought by bathers, and not from marine organic matter, and also linked to activities carried out in the pools (watergym vs swimming). Bromoform and dibromoacetic acid, the most abundant THM and HAA detected, were measured at levels up to 18-fold greater than the maximum contaminant levels of 60 and 80 μg/L fixed by US.EPA in drinking waters. The correlations between these disinfection byproducts and other environmental factors such as nitrogen, pH, temperature, free residual chlorine, UV₂₅₄, chloride and bromide concentrations, and daily frequentation were examined. Because thalassotherapy and seawater swimming pools (hotels, cruise ships,…) are increasing in use around the world and because carcinogenic and mutagenic brominated byproducts may be produced in chlorinated seawater swimming pools, specific care should be taken to assure cleanliness of users (swimmers and patients taking the waters) and to increase water circulation through media filters to reduce levels of brominated byproducts.     

Constructing users in the smart grid—insights from the Danish eFlex project

The smart grid is promoted as one of the key elements in a low-carbon transition in many countries. In Denmark, the dominant framing of the smart grid emphasises the challenge of integrating much more wind power into the electricity system and using electricity for heating (heat pumps) and transport (electric cars). In the process of radically transforming the electricity system, strategic system builders need to align many forces, including consumers, who play an important role in the functioning of such large networked systems. System builders need to explore, for instance, whether and how users can be motivated to be flexible in relation to moving electricity consumption over time. This paper reports on one of the first smart-grid-related projects in Denmark in which consumer aspects have been central and where potentials for flexible electricity consumption have been tested. The aim of the paper is to explore what can be learned from such experiments and which roles they play in the construction of the smart grid. In this context, the concept of the ‘aligned user’ is introduced.     

Characterization of nickel manganite NTC thermistor films prepared by aerosol deposition at room temperature

NiMn₂O_4+δ thermistor thick films have been successfully deposited by the so-called Aerosol Deposition Method (ADM) at room temperature on alumina substrates, Si-wafers, as well as on special planar four-wire interdigital electrode structures for high-precision electrical characterization. The NTCR films are homogeneous, completely dense and scratch resistant. Both as-deposited and tempered, the NTCR films exhibit a cubic spinel structure. Between 25 °C and 90 °C, the NTCR film resistance behaves as it is typical for variable range hopping (VRH) with parabolic density of states. As a result of moderate film tempering, the thermistor constant B and the specific resistance at 25 °C (ρ₂₅) decrease from 4250 K to 4020 K and 65 Ω·m to 40 Ω·m respectively, and are close to bulk values. In combination with the excellent reproducibility of the ρ₂₅ and B values, AD processing of films appears to be a promising alternative for classical ceramic bulk processes.     

Optimization of LED‐based light blendings for object presentation

This study looks at the perceived quality of light‐emitting diode (LED)‐based lighting of various colors. The objective was to find out whether LEDs could provide better (i.e., more relevant and acceptable) lighting than that which is obtained with standard halogen or fluorescent sources. The perception of objects was assessed under different lighting schemes. Subjects were invited to add red, cyan and/or amber to white LED‐based light to match the halogen and fluorescence rendering on specific targets: a color chart and a painting. They were also asked to rate the difference between the two, and to express their preference. The results obtained for the perception of LED‐based lighting were quite positive. Color blendings of LED light were found to provide illuminated situations similar to halogens or fluorescent sources. These blendings were well accepted, and indeed often preferred, although the color rendering index (CRI) was always low. This indicates that the CRI as it stands is inadequate to characterize the color rendering of solid‐state light sources, and needs to be updated. LED‐based lighting systems seem to have considerable potential for use in shops and display units, where they may well outperform existing lighting systems. © 2009 Wiley Periodicals, Inc. Col Res Appl, 34, 310–320, 2009     

Iron compounds electrodeposited onto a transparent semiconductor: Synthesis and characterisation by UV-vis spectroscopy

Homogeneous thin layers of lepidocrocite, green rust incorporating chloride anions (GRCl-GR1) and green rust incorporating sulphate anions (GRSO₄-GR2) were successfully electrodeposited onto tin dioxide substrate (SnO₂). The UV-vis spectroscopy absorbance, measured just after synthesis, increases linearly with the amount of iron compounds confirming that the electrodeposition is a homogeneous process. From the spectra, the absorption coefficients were determined for the three compounds. The monitoring by UV-vis spectroscopy measurements in real time of the oxidation in the air of the two unstable compounds, GRCl and GRSO₄, shows that the two green rusts have a different behaviour due to their own structure. The presence of an isobestic point in the case of GRSO₄ translates one equilibrium with its oxidised compound. This phenomenon is not observed for GRCl, however, the characteristic variation of the absorbance in the high wavelengths gives information on its oxidation reaction. From simple measurements, fruitful information on green rusts is obtained and this experimental system may be applied to other unstable solid compounds.     

Fabrication and evaluation of solid-oxide fuel cell anodes employing reaction-sintered yttria-stabilized zirconia

This paper reports on the fabrication and performance of solid-oxide fuel cell (SOFC) anodes utilizing yttria reaction-sintered zirconia (YRSZ). Through the reaction-sintering process, the technical-grade YSZ commonly used in the Ni-YSZ anode cermet is replaced with lower-cost ZrO₂ and Y₂O₃ materials. When sintered in the presence of nickel oxide, ZrO₂ and Y₂O₃ form cubic-phase YSZ at temperatures characteristic of SOFC processing (1400-1550 °C). Reaction sintering enables the formation of YSZ during cell fabrication, reducing SOFC anode raw-materials cost and the number of SOFC-fabrication processes. This paper reports the results of a broad range of characterization and performance measurements to evaluate the YRSZ material, including (1) crystal structure, (2) morphology, (3) pore-size distribution, (4) electronic resistivity, (5) fracture strength, (6) gas transport and catalytic activity, and (7) electrochemical performance. Material properties and performance are found to be comparable to or better than equivalent materials fabricated by conventional processes.     

拉拉君堡的采收之旅

9月我从上海出发，坐了十多个小时的飞机经巴黎辗转到达波尔多，从机场驱车沿着齐隆河（Gironde）左岸北上高梅多克（Haut Medoc），20分钟后司机提醒我到达了这条公路上的第一家列级酒店。     

Mechanical properties and corrosion behavior of lead-silicon carbide fiber and lead-carbon fiber composites made by electrodeposition

Multifilament silicon carbide fibers (Nippon Carbon, Nicalon type) and carbon fibers (Thornel, Pan T 300 and Pitch type) were used to produce lead-matrix composite materials for battery plate grid applications. Lead was impregnated into the fibers by electrodeposition from fluoborate baths. The electrical conductivity of carbon fibers was sufficient for direct electroplating; silicon carbide fibers were electroless plated with copper beforehand. The experimental conditions for good penetration of lead into the fiber tows were determined.Unidirectional composite samples with a fiber volume fraction of 5 to 25% were prepared from both lead impregnated fiber sheets and rods by hot-pressing (280°C, 50 MPa, 5–30 mm). The flexural strength and modulus of these samples were measured as a function of the infiltration current density and of the fiber volume fraction. Ultimate strengths in the range 300–400 MPa were attained for both lead-silicon carbide and lead-carbon composites, at a fiber volume fraction of about 25%. These latter composites exhibited a good corrosion resistance towards 38.5 wt-% sulfuric acid under non-anodic conditions.