Has the burden and distribution of PCBs and PBDEs changed in European background soils between 1998 and 2008? Implications for sources and processes

Background soils were collected from 70 locations on a latitudinal transect in the United Kingdom and Norway in 2008, ten years after they had first been sampled in 1998. The soils were analyzed for polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and organochlorine pesticides (OCs), to see whether there had been any change in the loadings or distributions of these persistent organic pollutants (POPs). The same transect has also been used to sample air between the mid-1990s and the present, so the air and soil spatial and temporal trends provide information on air-soil transfers, source-receptor relationships, long-range atmospheric transport (LRAT), and recycling phenomena. Comparisons of the 2008 and 1998 data sets show a general decline for PBDEs in surface soil, and a smaller averaged net decline of PCBs. Changes between the years were observed for total POP concentrations in soil and also for correlations with site and sample characteristics assumed to affect those concentrations. POP concentrations were correlated to distance and strength of possible sources, a relationship that became weaker in the 2008 data. Fractionation, a commonly discussed process for the global cycling of POPs was also lost in the 2008 data. As in 1998, soil organic matter content continues to have a strong influence on the loadings of POPs in surface soils, but changes in the PCB loads were noted. These factors indicate an approach to air-surface soil equilibrium and a lessening of the influence of primary sources on POP concentrations in soil between 1998 and 2008.     

Illustrating sensitivity and uncertainty in environmental fate models using partitioning maps

Variations of model predictions of the environmental fate of organic contaminants are usually analyzed for only one or at most a few selected chemicals, even though parameter sensitivity and contribution to uncertainty are widely different for different chemicals. A graphical method is introduced that allows for the comprehensive investigation of model sensitivity and uncertainty for all persistent organic nonelectrolytes at the same time. This is achieved by defining a two-dimensional hypothetical "chemical space" as a function of the equilibrium partition coefficients between air, water, and octanol (KOW, KAW, KOA), and plotting sensitivity and/or uncertainty of a specific model result to each input parameter as a function of this chemical space. The approach is illustrated for the bulk phase concentrations in air, water, soil, and sediment calculated by a level III model. Colored contour maps facilitate the identification of those input parameters that cause a high output variation of hypothetical and real chemicals. They also allow for the easy categorization of chemicals in terms of common parameter sensitivities, and thus comparable environmental behavior. Sensitivity varies with the mode of emission and the degradability of the chemicals, making it necessary to develop multiple sets of contour maps. Comparison of these sets of maps in turn allows the investigation of how parameter sensitivities change as a result of changes in mode of emission and persistence. The presented method can be used for investigating the sensitivity of any prediction obtained with any linear fate model that characterizes the partitioning behavior of organic chemicals with KAW, KoW, and KOA. Once the sensitivity maps have been constructed for a given environmental scenario, it is possible to perform a sensitivity analysis for a specific chemical by simple. placement of the substances' partitioning combinations within the chemical space. The maps can further contribute to the mechanistic understanding of a model's behavior, can aid in explaining observations of divergent environmental behavior of related substances, and can provide a rationale for grouping chemicals with similar model behavior, or for selecting representative example chemicals for a model investigation. They can also help in deciding when accurate and precise knowledge of physical chemical property data is crucial and when approximate numbers suffice to conduct a model investigation.     

Ageing and work-hardening behaviour of a commercial AA7108 aluminium alloy

In the 7xxx aluminium alloying system several mechanisms influence the hardening behaviour of the alloys, e.g. particle size and distribution, dislocation density and alloying elements in solid solution. This work is an experimental study of ageing and work-hardening considering a commercial AA7108 alloy in the as-cast and homogenized condition. Tensile specimens have been exposed to a solution heat treatment and a two-step age-hardening treatment with varying time at the final temperature. The tensile data for the different tempers have been evaluated in elucidation of already existing models based on a one-parameter framework. The precipitate size and distribution have been further investigated in the transmission electron microscope for a selection of tempers, and the influence of these parameters on the work-hardening behaviour has been discussed.     

Surveying and digital workflow in energy performance retrofit projects using prefabricated elements

Due to the need for improving the energy efficiency of existing buildings, various methods for energy retrofitting are being developed. One such initiative is the TES Energy Façade project, a joint European academia and industry project under the umbrella of the WoodWisdom Net research platform. The project has developed a systematic approach for using prefabricated timber-framed elements that can be assembled in front of an existing façade. The TES approach requires a detailed and precise documentation of the as-built/as-maintained conditions of the existing façade. This paper discusses the approach for the surveying and documentation of a building's existing state and the need to establish a continuous digital chain that encompasses the various project stages from the survey to the site assembly of the elements. Technologies such as 3D laser scanning and BIM are efficient tools in the process but are not yet sufficiently developed to handle all of the challenges in renewal and retrofit projects.     

The transportability of multisystemic therapy to Sweden: Short-term results from a randomized trial of conduct-disordered youths.

This randomized clinical trial assessed the effectiveness of multisystemic therapy (MST) for 156 youths who met the diagnostic criteria for conduct disorder. Sweden's 3 largest cities and 1 small town served as the recruiting area for the study. A mixed factorial design was used, with random allocation between MST and treatment as usual groups. Assessments were conducted at intake and 7 months after referral. With an intention-to-treat approach, results from multiagent and multimethod assessment batteries showed a general decrease in psychiatric problems and antisocial behaviors among participants across treatments. There were no significant differences in treatment effects between the 2 groups. The lack of treatment effect did not appear to be caused by site differences or variations in program maturity. MST treatment fidelity was lower than that of other studies, although not clearly related to treatment outcomes in this study. The results are discussed in terms of differences between Sweden and the United States. One difference is the way in which young offenders are processed (a child welfare approach vs. a juvenile justice system approach). Sociodemographic differences (e.g., rates of poverty, crime, and substance abuse) between the 2 countries may also have moderating effects on the rates of rehabilitation among young offenders. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Die Dywidag‐Versuchsschale in Wiesbaden‐Biebrich von 1931

The Dywidag Test Shell in Wiesbaden‐Biebrich from 1931 – A Contribution to the Early History of Reinforced Concrete Shell Construction in Germany In 1931, a photo was taken in Wiesbaden that made history in the field of engineering: A group of employees of the construction company Dyckerhoff & Widmann posed on a reinforced concrete test shell being just a few centimeters thick. To date, this experimental construction is presented as a symbol of the beginnings in concrete shell construction in numerous publications in Germany as well as in other countries. The paper deals with the lesser‐known circumstances of the erection of the test shell as well with its colorful history. The building does not only document the early history of shell construction. It also shows the challenges that may occur when protecting a monument of construction and industrial history that is not usable or economically exploitable.