Benchmarking on the evaluation of major accident-related risk assessment

This paper summarises the main results of a European project BEQUAR (Benchmarking Exercise in Quantitative Area Risk Assessment in Central and Eastern European Countries). This project is among the first attempts to explore how independent evaluations of the same risk study associated with a certain chemical establishment could differ from each other and the consequent effects on the resulting area risk estimate. The exercise specifically aimed at exploring the manner and degree to which independent experts may disagree on the interpretation of quantitative risk assessments for the same entity. The project first compared the results of a number of independent expert evaluations of a quantitative risk assessment study for the same reference chemical establishment. This effort was then followed by a study of the impact of the different interpretations on the estimate of the overall risk on the area concerned. In order to improve the inter-comparability of the results, this exercise was conducted using a single tool for area risk assessment based on the ARIPAR methodology. The results of this study are expected to contribute to an improved understanding of the inspection criteria and practices used by the different national authorities responsible for the implementation of the Seveso II Directive in their countries. The activity was funded under the Enlargement and Integration Action of the Joint Research Centre (JRC), that aims at providing scientific and technological support for promoting integration of the New Member States and assisting the Candidate Countries on their way towards accession to the European Union.     

Stahlbetonträger mit Öffnungen. Ein vereinfachtes Bemessungskonzept

Reinforced Concrete Beams With Openings – A Simplified Design Concept – A comprehensive design concept for reinforced concrete beams with large openings was presented in Beton‐ und Stahlbetonbau 97, booklet 3, 2002. In recent years six laboratory tests were carried out to verify the design concept. Additionally extensive Finite Element computations with physically nonlinear material models were conducted to analyse the structural behaviour of reinforced concrete beams with opening groups. In this paper a simplified design concept for reinforced concrete beams with large openings and opening groups is presented which is based on the results of the test series and the FE‐computations.     

Thermal properties of Sn-based solder alloys

During last few decades, emerging environmental regulations worldwide, more notably in Europe and Japan, have targeted the elimination of Pb usage in electronic assemblies due to the inherent toxicity of this element. This situation drives to the replacement of the Sn–Pb solder alloy of eutectic composition commonly used as joining material to suitable lead-free solders for microelectronic assembly. Sn-based alloys containing Ag, Cu, Bi, and Zn are potential lead-free solders, usually close to the binary or ternary eutectic composition. For this reason a great effort was directed to establish reliable thermophysical data fundamental to interpret the solidification process and fluidity of alloys belonging to these systems. In this work, an analysis of the solidification process of pure Sn, binary Sn–Ag, Sn–Cu, Sn–Bi, Sn–Zn, Sn–Pb and ternary Sn–Ag–Cu eutectic alloys was carried out using computer aided-cooling curve analysis and differential scanning calorimetry.     

Effect of recycled content and rPET quality on the properties of PET bottles,part II: Migration

Polyethylene terephthalate (PET) bottles were produced from three types of recycled PET (rPET) with four levels of recycled content. The migration of substances from these bottles to water was studied. Several migrated substances were detected. The migrated amounts of acetaldehyde and ethylene glycol complied with the limits given in the food contact material (FCM) legislation. Migration of 2-methyl-1,3-dioxolane was below the limit of 10 μg·L⁻¹, which is conventionally applied for non-intentionally added substances (NIAS) not classified as ‘carcinogenic’, ‘mutagenic’ or ‘toxic to reproduction’ (CMR). Limonene, acetone, butanone and furan were also detected as migrants, of which limonene is a natural fragrant, and the other three are probably residues from solvents used to clean and protect the mould at the small-scale production facility. Finally, benzene and styrene were also found as migrants from rPET. These migrants appear to originate from heat-induced reactions within the PET matrix, which involve contaminants. The formation of benzene in rPET is attributed to polyvinylchloride as contaminant. The migrated amounts of benzene from the PET bottles with recycled content to the water simulant are relatively small (0.03–0.44 μg·L⁻¹) after 10 days at 40°C. Consequently, the margin of exposure is 3.10⁵–8.10⁶. Hence, the level of concern for the public health is low, and the migrated amount represents a low priority for risk management. The FCM legislation demands a risk assessment for migrating NIAS. Depending on the underlying data and exposure scenario, different threshold limits in the food can be derived which can still be considered as safe.     

Tunable double quantum dots in InAs nanowires defined by local gate electrodes

We report on low-temperature transport measurements on single and double quantum dots defined using local gates to electrostatically deplete InAs nanowires grown by chemical beam epitaxy. This technique allows us to define multiple quantum dots along a semiconducting nanowire and tune the coupling between them.     

Photon migration through a turbid slab described by a model based on diffusion approximation. I. Theory

The diffusion approximation of the radiative transfer equation is a model used widely to describe photon migration in highly diffusing media and is an important matter in biological tissue optics. An analysis of the time-dependent diffusion equation together with its solutions for the slab geometry and for a semi-infinite diffusing medium are reported. These solutions, presented for both the time-dependent and the continuous wave source, account for the refractive index mismatch between the turbid medium and the surrounding medium. The results have been compared with those obtained when different boundary conditions were assumed. The comparison has shown that the effect of the refractive index mismatch cannot be disregarded. This effect is particularly important for the transmittance. The discussion of results also provides an analysis of the role of the absorption coefficient in the expression of the diffusion coefficient.     

Photon migration through a turbid slab described by a model based on diffusion approximation. II. Comparison with Monte Carlo results

In our companion paper we presented a model to describe photon migration through a diffusing slab. The model, developed for a homogeneous slab, is based on the diffusion approximation and is able to take into account reflection at the boundaries resulting from the refractive index mismatch. In this paper the predictions of the model are compared with solutions of the radiative transfer equation obtained by Monte Carlo simulations in order to determine the applicability limits of the approximated theory in different physical conditions. A fitting procedure, carried out with the optical properties as fitting parameters, is used to check the application of the model to the inverse problem. The results show that significant errors can be made if the effect of the refractive index mismatch is not properly taken into account. Errors are more important when measurements of transmittance are used. The effects of using a receiver with a limited angular field of view and the angular distribution of the radiation that emerges from the slab have also been investigated.