Qualitätsmanagement bei der Herstellung von Chemieapparaten aus Sonderwerkstoffen

Quality Management during the Fabrication of Chemical Equipment Made of Special Materials Optimizing a material's resistance to corrosion by the addition of alloying elements up to their solubility limits will make it increasingly difficult to use these frequently unstable alloys for the manufacture of chemical plant. The requirements these materials have to meet in the manufacture of chemical plant in terms of manufacturing technology and quality management, are becoming increasingly stringent. The current situation, for example in the manufacture of domed heads of pressure vessels, forgings, heat exchangers, and filter screens with a high specific surface area as a constituent part of stirred suction filters using advanced metallic materials, is not very satisfactory. Results of fabrication tests necessary for pressure vessel manufacture as well as in-service failures frequently demonstrate insufficient expertise of workshops dealing with high-alloy stainless steels and nickel-based materials. That the in-service failure of compoents clearly leads to considerable costs due to maintenance, delays in supply, and production downtimes. The economic consequences can be substantial. The aim of this paper is to highlight sensitive areas by demonstrating the impact of unintentional and unnoticed fabrication-related changes in welding parameters and to provide information on easily applicable methods of monitoring techniques.     

Fabrication of diamond nanowires for quantum information processing applications

We present a design and a top-down fabrication method for realizing diamond nanowires in both bulk single crystal and polycrystalline diamond. Numerical modeling was used to study coupling between a Nitrogen Vacancy (NV) color center and optical modes of a nanowire, and to find an optimal range of nanowire diameters that allows for large collection efficiency of emitted photons. Inductively coupled plasma (ICP) reactive ion etching (RIE) with oxygen is used to fabricate the nanowires. Drop-casted nanoparticles (including Au, SiO₂ and Al₂O₃) as well as electron beam lithography defined spin-on glass and evaporated Au have been used as an etch mask. We found Al₂O₃ nanoparticles to be the most etch resistant. At the same time FOx e-beam resist (spin-on glass) proved to be a suitable etch mask for fabrication of ordered arrays of diamond nanowires. We were able to obtain nanowires with near-vertical sidewalls in both polycrystalline and single crystal diamond. The heights and diameters of the polycrystalline nanowires presented in this paper are ≈ 1 μm and 120–340 nm, respectively, having a 200 nm/min etch rate. In the case of single crystal diamond (types Ib and IIa) nanowires the height and diameter for different diamonds and masks shown in this paper were 1–2.4 μm and 120–490 nm with etch rates between 190 and 240 nm/min.     

Parallel FTIR-ATR and gravimetrical in-situ measurements on sodium alanate powder samples during hydrogen desorption

An experimental set-up has been developed to carry out in-situ measurements on hydrogen storage materials. It has been used to perform FTIR–ATR measurements on sodium alanate samples during hydrogen desorption and, in parallel, to perform gravimetrical measurements on the same sample. The ATR spectra showed the typical broad Al–H vibrational features, changing according to the phase change the material undergoes during the load cycle. It is shown that the absorbance of the material at these bands and the hydrogen content correspond to each other in a reproducible way. This behavior may be used to measure the hydrogen mass released by an alanate hydrogen reservoir by measuring the optical absorbance at defined wavelengths. In this paper the results of these experiments that may give rise to the realization of a level sensor in future hydrogen storage applications are presented.     

Durability of fire retardant treated wood products at humid and exterior conditions review of literature

Fire retardants may considerably improve the fire properties of wood products, but the durability, e.g. in exterior applications, has not been addressed fully. This paper reviews the existing knowledge and experience mainly from the USA with the aim of supporting further development in Europe. The review is concentrated on pressure impregnated fire retardant treated wood products which have the best opportunities for increased durability. Copyright © 2001 by John Wiley & Sons, Ltd.     

Automated Karl Fischer titration for liquid samples – Water determination in edible oils

In the field of food analysis, rapid measurements and results are generally of high importance. The Karl Fischer titration (KFT), a chemical method for determining water content, and its automated performance enhance rapidity by giving the opportunity to deal with more samples in less time; automated sequences can include different determination methods and sample treatments. Moreover, automation can improve reproducibility and precision.     

Processing blackcurrants dramatically reduces the content and does not enhance the urinary yield of anthocyanins in human subjects

Blackcurrant (BC) fruits are a rich source of biologically active anthocyanins but little is known of the anthocyanin content of commonly consumed BC products or how processing affects the absorption. We report that whereas fresh and frozen whole BC were a rich source of anthocyanins, containing 897 and 642 mg (100 g FW)⁻¹ of total anthocyanins the levels in all other products were substantially lower (0.05–10.3% of the levels in fresh fruit). Further, when the absorption and excretion of BC was assessed in volunteers consuming a portion (100 g) of frozen whole BC (642 mg total anthocyanins) and, 300 g of a BC drink made by diluting concentrated syrup (33.6 mg total anthocyanins), only small quantities of BC anthocyanins were excreted in urine (fruit, 0.053 ± 0.022%; drink, 0.036 ± 0.043%; mean percent urinary yield ± SD) and they were not detected in plasma. These data indicate that fresh and frozen BC, but not processed products, are rich sources of anthocyanins but, regardless of the food source, these anthocyanins are poorly bioavailable.