A posteriori control of modelling errors in linear elasticity

The concept of adaptive error control for finite element Galerkin discretizations has more recently been extended from the pure treatment of the discretization errors [1], [2] also to the control of modelling errors [4], [5]. These techniques can be employed for a rigorous justification of the local choice of the model out of a given hierarchy with increasing complexity. In the present paper the concept is exemplified by a hierarchy of linear-elastic models, consisting of a basic model with constant E modulus and an improved model with oscillating E modulus. Significant reduction of the computational complexity can be achieved by a proper choice of the model in different subdomains, automatically chosen by the error estimators. Several error indicators are investigated in the context of goal oriented error estimation. Their efficiency is compared by means of finite element simulations [3] of an elementary example. (© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

High-performance liquid chromatography of lactose with evaporative light scattering detection, applied to determine fine particle dose of carrier in dry powder inhalation products

A method for quantification of the fine particle dose of lactose is described, using a hydrophilic interaction chromatography (HILIC) method and evaporative light scattering detection. The HILIC method used an aminopropyl column and a mobile phase consisting of acetonitril/water (80/20, v/v) for isocratic elution. Sensitive chromatography was obtained using a low concentration of water in the extraction solvent. The detection limit (RSD<10%) at an injection volume of 10 microL is 10 microg/mL. Linearity was obtained in the range of 10-80 microg/mL (R(2)>0.99). A relative standard deviation (RSD) of 0.5% (N=6) demonstrated good precision of the optimized method.     

Originalarbeiten

Es wird eine Methode zur Anreicherung des Isotops, ¹⁹⁶Hg durch isotopenselektive Pholooxydation von Quecksilberdampf beschrieben. Sie beruht auf der Benutzung von Niederdruck-Gasentladungslampen, die mit ¹⁹⁸Hg gefüllt sind und so betrieben werden, daß eine schwache Selbstabsorption auftritt, und auf der Anwendung einer Filterschicht mit natürlichem Quecksilberdampf. Im günstigsten Falle wurde das Verhältnis der Häufigkeiten der Isotope ²⁰²Hg/¹⁹⁶Hg vom natürlichen Wert 200 auf 1,5 gebracht. Die maximale Isotopenhäufigkeit von ¹⁹⁶Hg im Reaktionsprodukt betrug über 5 Atotn-%.     

Interpolation of Classical Lorentz Spaces1

We describe the K-functional and identify the real interpolated spaces of general quasi–Banach couples of classical Lorentz spaces. Applications are given which include interpolation of spaces of Lorentz–Zygmund type.     

The Synthesis and Crystal Structure of Hg3TeI4

The structure of cubic Hg₃TeI₄ was determined from powder data. The four positions of the cubic closestpacking of the anions are statistically occupied by 0.8 Te-atoms and 3.2 I-atoms. The two types of tetrahedral holes are occupied to the extent of 2/4 and 0.4/4, respectively, by Hg-atoms. With an ordered model of lower symmetry, the stoichiometric composition can be explained and a homogeneous charge distribution can be achieved. The ordered model contains regions of the structure of red HgI₂, which are connected by fragments of the SiS₂-type.     

Study of liquid crystal space groups using controlled tilting with cryogenic transmission electron microscopy

We developed a method that enables differentiation between liquid crystalline-phase particles corresponding to different space groups. It consists of controlled tilting of the specimen to observe different orientations of the same particle using cryogenic transmission electron microscopy. This leads to the visualization of lattice planes (or reflections) that are present for a given structure and absent for the other one(s) and that give information on liquid crystalline structures and their space groups. In particular, we show that we can unambiguously distinguish among particles having the inverted micellar cubic (space group Fd(3)m, 227), the inverted bicontinuous gyroid (space group Ia(3)d, 230), the inverted bicontinuous diamond (space group Pn(3)m, 224), and the inverted bicontinuous primitive cubic structure (space group Im(3)m, 229).     

Methanol – die Basischemikalie

Today methanol is produced from synthesis gas derived from coal and natural gas. However carbon dioxide and hydrogen obtained from water electrolysis with renewable energy have the potential to play a leading role as fuel, energy raw material and chemical feedstock. As a liquid energy storage system it can be used to easily transport electric power conserved in chemical bonds with unparalleled efficiency. Homologisation making use of the Mobil zeolite processes (MTG, MTO, MTA) for instance, or via the methanol derived platform chemicals methyl formate and dimethyl ether, the majority of organic chemicals established in chemical industry is available. Through its diverse of applications methanol has the potential to substitute crude oil and natural gas as the leading feedstock for organic chemicals.