On the use of the partitioning approach to derive Environmental Quality Standards (EQS) for persistent organic pollutants (POPs) in sediments: a review of existing data

A review of experimental data has been performed to study the relationships between the concentration in water, pore water and sediments for different families of organic contaminants. The objective was to determine whether it is possible to set EQS for sediments from EQS defined for surface waters in the Daughter Directive of the European Parliament (COM (2006) 397). The analysis of experimental data showed that even though in some specific cases there is a coupling between water column and sediments, this coupling is rather the exception. Therefore it is not recommendable to use water column data to assess the chemical quality status of sediments and it is necessary to measure in both media. At the moment EQS have been defined for the water column and will assess only the compliance with good chemical status of surface waters. Since the sediment toxicity depends on the dissolved pore water concentration, the EQS developed for water could be applied to pore water (interstitial water); hence, there would be no need of developing another set of EQS. The partitioning approach has been proposed as a solution to calculate sediment EQS from water EQS, but the partitioning coefficient strongly depends on sediment characteristics and its use introduces an important uncertainty in the definition of sediment EQS. Therefore, the direct measurement of pore water concentration is regarded as a better option.     

Dielectric Properties of Acceptor-Doped (Ba,Ca)(Ti,Zr)O3 Ceramics

The dielectric properties of (Ba,Ca)(Ti,Zr)O₃ ceramics containing various acceptor and donor dopants on the B sites have been studied. Formation of charge compensating complexes between acceptors, donors and oxygen vacancies has been observed. All acceptors cause a reduction of the Curie point. The maximum dielectric constant increases with the average grain size almost independent of the acceptor incorporated. Ceramics fired in reducive atmospheres reveal pronounced changes of the dielectric properties after annealing in oxidizing atmosphere. In particular the losses and the maximum dielectric constants are significantly affected by the annealing time, temperature and partial pressure of oxygen.     

Kinetic Process of Reoxidation of Base Metal Technology BaTiO3-Based Multilayer Capacitors

Base metal technology, mainly using Ni electrodes in multilayer ceramic capacitors (MLCCs), is now well established. This technology requires a so-called reoxidation treatment after sintering the MLCCs in a reducing atmosphere to guarantee a sufficient electrical reliability. Large numbers of electrodes, and production of physically larger components for high-voltage components, are two technological trends that make the control of the reoxidation process rather difficult. The reoxidation process has been studied to determine oxygen diffusion pathways into commercial MLCCs, using ¹⁸O tracer diffusion and finite element calculations. In MLCCs oxygen diffusion mainly occurs along the Ni electrodes. Furthermore, the reoxidation process is mostly controlled by the thermodynamic potential of the Ni/NiO equilibrium in the interior of the capacitor, but it is the short circuit diffusion along the interface of the electrode that controls the kinetics of the oxygen transport into the interior of the capacitor device.     

Hydroxyl Defect Effect on Reoxidation of Sc‐Doped (Ba,Ca)(Ti,Zr)O3 Fired in Reducing Atmospheres

The behavior of grain and grain‐boundary conductivity of acceptor (Sc)‐doped (Ba,Ca)(Ti,Zr)O₃ ceramics sintered in moist reducing atmosphere and subsequently reoxidized in dry and moist atmosphere was investigated by means of impedance spectroscopy (IS). In moist firing atmosphere, water vapor was found to react with oxygen vacancies, forming positively charged hydroxyl defects on regular oxygen sites in the crystal lattice. Proton hopping is considered to raise the ionic conductivity significantly. Therefore, hydroxyl defects in turn influence the grain conduction. Hydroxyl defects are also considered to be responsible for alternations of the dielectric maximum at the Curie point.     

Technische Richtlinie Biometrics for Public Sector Applications

Mit der Einführung neuer hoheitlicher Dokumente wie beispielsweise dem elektronischen Personalausweis, dem elektronischen Aufenthaltstitel oder Visa werden einheitliche Qualit?tsanforderungen und Anforderungen an die Interoperabilit?t bezüglich der eingesetzten Hard- und Softwarekomponenten für unterschiedliche biometrische Anwendungen gestellt. Der folgende Beitrag stellt die technische Richtlinie „Biometrics for Public Sector Applications“ des BSI vor, in der die verschiedenen Anforderungen strukturiert beschrieben und in Bezug zu verschiedenen hoheitlichen Anwendungen gesetzt werden.     

Modular Manufacturing Platform for Continuous Synthesis and Analysis of Versatile Nanomaterials

Nanoparticular materials have a great potential in various fields including technical and biomedical applications; to meet the specific requirements, a good control over the particle characteristics is mandatory. Addressing this, a modular system for the automated and continuous synthesis, workup, and analysis of a broad range of nanoparticles was developed. Application examples of inorganic (silica) and organic (polymersomes, niosomes) nanoparticles demonstrate the versatility of the production platform. Modules for downstream processing via a falling‐film microreactor or tangential flow filtration are presented. The hydrodynamic size as a key parameter is acquired in real time, with an inline dynamic light scattering device. All modules are controlled and operated by a process control system.     

Effects of Calcination Temperature and A/B Ratio on the Dielectric Properties of (Ba,Ca)(Ti,Zr,Mn)O3 for Multilayer Ceramic Capacitors with Nickel Electrodes

The electrical performance of multilayer ceramic capacitors (MLCCs) with Ni inner electrodes, made from (Ba,Ca)(Ti,Zr,Mn)O₃ (BCTZM), is closely related to the calcination temperature and the A/B ratio of the powder. For materials showing A/B = 1.000, the lifetime, the breakdown voltage, and the RC increase with higher calcination temperatures. No significant effect of the calcination temperature on RC and lifetime was found for materials showing A/B = 0.991. The isoelectric point of BCTZM is shifted toward higher pH values when the calcination temperature is decreased. The above results are attributed to the colloidal stability of aqueous BCTZM suspensions and the resulting green density of powder compacts.     

Elastic properties and electronic structure of vanadium silicides-a density functional investigation

Vanadium and silicon form several binary compounds; the most well characterized structures have the compositions V:Si = 3:1, 5:3, 6:5, 1:2. Spin-polarized density functional band-structure calculations using the projector augmented wave method have been carried out for the stable binary compounds in the Si–V system. As many rare earth and early transition metals are refractory materials, the study focuses on the ground state structures and their stabilities by determining their elastic properties. The magnetic properties are also investigated because structurally related Si–Mn compounds exhibit magnetism. All the silicides investigated were found to be refractory, hard, metallic materials and no magnetism was found in the ground state structures.