Reliability background of the Eurocodes. Support to the implementation, harmonization and further development of the Eurocodes

EN 1990 defines structural reliability as the ability of a structure to fulfil the specified requirements during the service life for which it has been designed; the notion covers safety, serviceability and durability. According to this definition, reliability is the concern of all parts of the whole suite of Eurocodes. In a more narrow sense of the word, reliability refers to the way uncertainties are dealt with in design and assessment by the use of partial factors or more advanced probabilistic methods. This JRC Technical Report introduces relevant basic notions such as uncertainty, probability, risk, member and system failure, time dependency, effects of deterioration and inspection; it focuses on the basic reliability requirements in EN 1990 related to the persistent as well as the accidental and seismic design situations, paying special attention to the new materials included in the second generation of the Eurocodes (glass, fibre reinforced polymers and membrane structures). Attention is also given to the special problems that may arise in assessment of existing structures - observations, the various decision options and of typical reliability issues (updating, reduced targets). The report also describes explicit risk and full probability methods, and gives background for code calibrations. Finally, the annexes propose an overview of probabilistic models for actions, material properties and model uncertainties, as a reflection of the present state of knowledge in the various Eurocode subcommittees, working groups and horizontal groups, and a number of example applications.Peer reviewe

The geochemistry of brines and minerals from the Asse Salt Mine, Germany.

The chemistry and stable isotopes (18O, D) of highly concentrated chloride brines and minerals from the Asse salt mine in the north of the Federal Republic of Germany were studied. Chemical data indicate the occurrence of three types of brines: (a) Mg-Cl type, of carnallitite origin with Li < 30 mg/kg; (b) Na-Cl type brines, of rock salt origin, with Li > 100 mg/kg; and (c) almost pure MgCl2-type brines with Li > 100 mg/kg. The first group may be subdivided into brines with Li < 4.0 mg/kg and brines with Li between 18 and 30 mg/kg. Lithium is shown to be an efficient complementary tool in tracing the origin of the brines. The complex evolution of carnallitite-type brines is discussed in detail. Isotopic data of brines that were sampled directly from seepages (presumably unaltered) indicate that these brines are not a mixture with relatively fresh ground water from the overburden sediments. The stable isotope composition (18O and D) of hydration water in carnallite, kieserite and polyhalite sampled from the Asse mine were also studied. It is shown that water extracted from the so-called primary carnallite is isotopically different from water extracted from secondary carnallite. The isotopic fractionation factors for 18O and D between carnallite hydration water and mother solution were studied in the laboratory. Assuming that crystallization water of the so-called primary carnallite samples is not altered, the isotopic composition of the mother solution is evaluated

Systematic Screening of All Signal Peptides from Bacillus subtilis: A Powerful Strategy in Optimizing Heterologous Protein Secretion in Gram-positive Bacteria

Brockmeier U, Caspers M, Freudl R, Jockwer A, Noll T, Eggert T. Systematic Screening of All Signal Peptides from Bacillus subtilis: A Powerful Strategy in Optimizing Heterologous Protein Secretion in Gram-positive Bacteria. Journal of Molecular Biology. 2006;362(3):393-402