TiO2 thick films supported on reticulated macroporous Al2O3 foams and their photoactivity in phenol mineralization

TiO₂ thick films deposited on macroporous reticulated Al₂O₃ foams with pore size of 10 ppi and 15 ppi were prepared using dip coating from slurries of Aeroxide^® P25 nanopowder and precipitated titania. All prepared films have sufficiently good adhesion to the surface of the substrate also in case of strongly cracked films. No measurable release of deposited TiO₂ after repeated photocatalytic cycles was observed. The photocatalytic activity was characterized as the rate of mineralization of aqueous phenol solution under irradiation of UVA light by TOC technique. The best activity was obtained with Aeroxide^® P25 coated Al₂O₃ foam with the pore size of 10 ppi, annealed at 600 °C. The optimal annealing temperature for preparation of films from precipitated titania could be determined at 700 °C. Films prepared by sol-gel deposition technique were considerably thinner compared to coatings made of suspensions and their photocatalytic activity was significantly smaller.     

An internally heated composite gasket for diamond-anvil cells using the pressure-chamber wall as the heating element

The implementation of a heating element to a composite gasket for high-temperature applications in the diamond-anvil cell was developed based on a double-gasket assemblage. The heating element is a thin platinum wall that covers the central borehole of the metal–ceramic–metal composite gasket and interconnects the two metal component parts of the gasket. Applying electric powers up to 35 W to the two gasket metal components result in ring-like heating around the sample inside the pressure chamber with temperatures exceeding ～2000 K in individual cases. The ring-like distribution of the maximum temperature located at the pressure-chamber wall facilitates a homogeneous temperature distribution at the sample position. As a consequence of the concentration of the heating power to the pressure chamber region, gradients of surface temperatures, both at the gasket and the diamond anvil, appear to be more pronounced compared with those known for classical external electrical heating. Apart from the tests of the mechanical stability on high-pressure operation in the diamond anvil cell at room temperature, the influence of the anvils in contact with the gasket on the characteristic power–temperature curves, temperature gradients and thermal equilibration resulting from changes in electrical power settings have been evaluated within the scope of a series of experimental investigations.     

Die kationische Polymerisation von Ketenacetalen und die Darstellung und Charakterisierung von Poly(1,3-diketonen)

Ohne Zusammenfassung     

Die empirische Matrixkorrektur intermediärer Proben in der Röntgenspektrometrie

Very thin samples show proportionality between the intensity and the weight per unit area of the analyte. Matrix effects do not exist. The matrix effects of very thick samples suitably can be corrected by multiple regression according to Eq. (1). Between these two kinds of samples the intermediate ones are situated with the intensity of the analyte as a function of the weight per unit area of the sample as an additional parameter of correction.

It was shown that these samples can also be corrected by multiple regression without knowing the weight per unit area of the samples by using the weight per unit area of the analyte instead of its concentration according to Eq. (5). This was demonstrated by calculation with simulated standards.

In addition to the described effects the correction program Eq. (5) is able to correct for the influences of dust particle sizes and their depth distribution in the filter.

     

Die Restmatrix in der R?ntgenspektrometrie

Zusammenfassung Die üblichen Rechenansätze für die Matrixkorrektur setzen voraus, daß die Konzentrationen aller Matrixelemente bekannt sind. In der Praxis hat man es aber vielfach mit Proben zu tun, die eine unbekannte Restmatrix enthalten. Verwendet man die Konzentrationen der Matrixelemente für die Korrektur, so läßt sich der Einfluß dieser Restmatrix dadurch ausschalten, daß man ein quadratisches Glied für die Intensität des Analyten in den Rechenansatz einführt. Es besteht auch die Möglichkeit, die Intensitäten der Matrixelemente als Korrekturgrößen zu verwenden. In diesem Falle kann man die Intensität einer passend gewählten Streustrahlung zur Korrektur der Restmatrix in den Rechenansatz einführen. Die theoretischen Grundlagen dieser Verfahren werden behandelt.

---

The residual matrix in x-ray spectrometry

Summary The usual functions for the matrix correction presume that the concentrations of all matrix elements are known. But in practice one has frequently to deal with samples which contain an unknown residual matrix. If the concentrations of the matrix elements are used to carry out the correction the influence of this residual matrix can be governed by introducing a quadratic term of the analyte's intensity into the correcting function. It is also possible to use the intensities of the matrix elements as starting-point of the matrix correction. In this case one can introduce the intensity of a suitable chosen scattered radiation into the correcting function in order to correct for the residual matrix. The theoretical foundations of these procedures are discussed.

     

Bericht über die 4. Tagung Steine und Erden in Aachen 29. und 30.4.54

Ohne ZusammenfassungDie Vorträge sollen ausführlich in den Fachzeitschriften: Tonindustriezeitung undZement, Kalk, Gips erscheinen.