A Cost-Benefit Analysis of Fire Protection Systems Designed to Protect Against Exterior Arson Fires in Schools

Fires in school buildings caused by arson are a major problem in Sweden. The costs of these fires are disproportionately high compared to the costs of fires in buildings in general, and it has been shown that fires that start outside of the building in connection with an exterior wall, so called exterior fires are especially problematic. However, technical systems can be used to mitigate the consequences of arson fires in school buildings. In this paper a cost-benefit analysis is used to calculate cost-benefit ratios for four technical systems used to detect these types of fires

Tekniska system för att förhindra och begränsa anlagd brand– Slutrapport

The project “Arson - a societal problem” has been running with funding from a number of players since 2008. The project consists of a number of sub-projects and the work presented in this report was conducted within the sub-project: "Technical- and risk-based methods to prevent and mitigate the consequences of arson". The goal and purpose of the project was to develop and evaluate technical systems and engineering solutions to prevent and mitigate the consequences of arson in school buildings. The project has been reported in four interim reports. The main results of these interim reports and their findings have been summarized in this final report

c-Type Cytochrome-Dependent Formation of U(IV) Nanoparticles by Shewanella oneidensis

Modern approaches for bioremediation of radionuclide contaminated environments are based on the ability of microorganisms to effectively catalyze changes in the oxidation states of metals that in turn influence their solubility. Although microbial metal reduction has been identified as an effective means for immobilizing highly-soluble uranium(VI) complexes in situ, the biomolecular mechanisms of U(VI) reduction are not well understood. Here, we show that c-type cytochromes of a dissimilatory metal-reducing bacterium, Shewanella oneidensis MR-1, are essential for the reduction of U(VI) and formation of extracelluar UO (2) nanoparticles. In particular, the outer membrane (OM) decaheme cytochrome MtrC (metal reduction), previously implicated in Mn(IV) and Fe(III) reduction, directly transferred electrons to U(VI). Additionally, deletions of mtrC and/or omcA significantly affected the in vivo U(VI) reduction rate relative to wild-type MR-1. Similar to the wild-type, the mutants accumulated UO (2) nanoparticles extracellularly to high densities in association with an extracellular polymeric substance (EPS). In wild-type cells, this UO (2)-EPS matrix exhibited glycocalyx-like properties and contained multiple elements of the OM, polysaccharide, and heme-containing proteins. Using a novel combination of methods including synchrotron-based X-ray fluorescence microscopy and high-resolution immune-electron microscopy, we demonstrate a close association of the extracellular UO (2) nanoparticles with MtrC and OmcA (outer membrane cytochrome). This is the first study to our knowledge to directly localize the OM-associated cytochromes with EPS, which contains biogenic UO (2) nanoparticles. In the environment, such association of UO (2) nanoparticles with biopolymers may exert a strong influence on subsequent behavior including susceptibility to oxidation by O (2) or transport in soils and sediments

Rapid characterisation of vegetation structure to predict refugia and climate change impacts across a global biodiversity hotspot

Identification of refugia is an increasingly important adaptation strategy in conservation planning under rapid anthropogenic climate change. Granite outcrops (GOs) provide extraordinary diversity, including a wide range of taxa, vegetation types and habitats in the Southwest Australian Floristic Region (SWAFR). However, poor characterization of GOs limits the capacity of conservation planning for refugia under climate change. A novel means for the rapid identification of potential refugia is presented, based on the assessment of local-scale environment and vegetation structure in a wider region. This approach was tested on GOs across the SWAFR. Airborne discrete return Light Detection And Ranging (LiDAR) data and Red Green and Blue (RGB) imagery were acquired. Vertical vegetation profiles were used to derive 54 structural classes. Structural vegetation types were described in three areas for supervised classification of a further 13 GOs across the region.Habitat descriptions based on 494 vegetation plots on and around these GOs were used to quantify relationships between environmental variables, ground cover and canopy height. The vegetation surrounding GOs is strongly related to structural vegetation types (Kappa = 0.8) and to its spatial context. Water gaining sites around GOs are characterized by taller and denser vegetation in all areas. The strong relationship between rainfall, soil-depth, and vegetation structure (R2 of 0.8–0.9) allowed comparisons of vegetation structure between current and future climate. Significant shifts in vegetation structural types were predicted and mapped for future climates. Water gaining areas below granite outcrops were identified as important putative refugia. A reduction in rainfall may be offset by the occurrence of deeper soil elsewhere on the outcrop. However, climate change interactions with fire and water table declines may render our conclusions conservative. The LiDAR-based mapping approach presented enables the integration of site-based biotic assessment with structural vegetation types for the rapid delineation and prioritization of key refugia

Environmental concerns of fires : facts, figures, questions and new challenges for the future

International audienceThe effect of fires on the environment has been increasingly in the public eye since the chemical warehouse accident in the Sandoz facility in Schweizerhalle in November 1986. This paper presents a discussion of this accident together with a representative sample of other environmentally important case studies related to fires. Modes of interaction with the environment and potential transfer mechanisms are discussed. The impact of fire effluents in both the short and long terms and activities on the quantification of the environmental effect of fires are also presented. Some of the current environmental debates that are interacting with fire prevention and fire firefighting techniques are also discussed, outlining challenging remaining issues. Finally, insight on international action in response to these incidents and related standardisation activities under progress is presente

Some Experimental and Theoretical Aspects of Combustion Chemistry

An experimental apparatus is presented and discussed in terms of the range of combustion systems that can be studied using this apparatus. Based on this characterisation the effect of flame stoichiometry on the production of dioxin precursors is discussed. Results suggest control over flame stoichiometry could facilitate control of dioxin production. The results of laminar flame experiments are often interpreted using species profiles produced using detailed combustion models. Due to the lack of detailed kinetic data for key reactions these mechanisms contain a certain amount of uncertainty. The full experimental characterisation of any given reaction rate coefficient is difficult over the range of temperatures of interest in combustion modelling (300--2500 K). Therefore a theoretical approach to the full characterisation of an elementary reaction is presented. Ab initio results are presented mapping the Renner-Teller split, ground state potentials associated with the reaction of atomic carbon and nitric oxide (C+NO). A many-body expansion type fit is presented and results of quasiclassical trajectories (QCT) run on this surface are discussed. The results suggest that product branching should favour the thermodynamically most stable products (CO+N, 60%) over the range of temperatures considered. Both product branching and absolute rate coefficients are in as good agreement with experiments (CO+N, 60%). Statistical calculations based on the Rice-Ramsperger-Kassel-Marcus (RRKM) formalism were not, however, in good agreement with these results (CO+N, 73%) and the RRKM complex lifetimes in particular were found to be much shorter than the QCT equivalent. We suggest that this may largely be due to the suppression of the internal equilibria in the RRKM calculations. Application of modified Arrhenius type fits of the rate coefficients to the modelling of two laminar flames where the importance of the reaction of atomic carbon and NO has previously been established, is presented. The importance of the temperature dependence of rate coefficients in combustion modelling is discussed. Finally, RRKM results are presented for the reaction of imidogen and nitric oxide (NH+NO). This reaction has recently been characterised by S. Walch and G.C. Schatz in an analogous manner to our characterisation of the C+NO reaction. Statistical calculations suggest that the thermodynamically least stable products (N2O+H) are dominant (85%) over the range of energies studied. The mechanism for this is essentially entropic as the saddle point associated with the decomposition of the intermediate complex (cis-HNNO) into the thermodynamically most stable products is very narrow. A discussion of the effect of the inclusion of anharmonicity on the complex lifetime is also presented