Identification of inorganic pigments used in porcelain cards based on fusing Raman and X-ray fluorescence (XRF) data

Raman spectroscopy and X-ray fluorescence (XRF) spectroscopy are often used as complementary techniques that are well suited for the analysis of art objects because both techniques are fast, sensitive, and noninvasive and measurements can take place in situ. In most of these studies, both techniques are used separately, in the sense that the spectra are evaluated independently and single conclusions are obtained, considering both results. This paper presents a data fusion procedure for Raman and XRF data for the characterization of pigments used in porcelain cards. For the classification of the analyzed points of the porcelain cards principal component analysis (PCA) was used. A first attempt was made to develop a new procedure for the identification of the pigments using a database containing the fused Raman-XRF data of 24 reference pigments. The results show that the classification based on the fused Raman-XRF data is significantly better than the classifications based on the Raman data or the XRF data separately.     

Emittance measurements of solids above 2000 deg C

A method of measuring the emittance of solids above 2000 deg C through the use of a solar furnace has been developed. Two techniques involving specialized instrumentation, for performing the necessary measurements were investigated. Initial experiments showed that both techniques were suitable and that the specified instruments were adaptable for making the required measurements.     

Microstructural aspects of neutron embrittlement of reactor pressure vessel steels - A view from positron annihilation spectroscopy

A comprehensive review of positron annihilation studies of Cr---Mo---V reactor pressure vessel (RPV) steels (Soviet type 15Kh2MFA) in unirradiated and neutron irradiated states is presented. The influences of lattice defects, impurity atom distribution, irradiation temperature, flux and fluence of fast neutrons on positron annihilation parameters, especially during isochronal annealing, are discussed in terms of the positron trapping model. In contrast to the literature, where irradiation-enhanced Cu precipitates and solute coated microvoids are thought to be major defect types responsible for strengthening and hence embrittling of RPV steels, we suggest irradiation-induced precipitates, i.e. probably carbides, to play this role. Possibilities to probe this model are suggested.     

Interaction of nonionic polymers at a clay interface

The structure and dynamics at the interface of swelling clays (smectites) are crucial to such diverse applications as drilling for oil, cosmetics, paints, water treatment, or chemical reactions. From our previous NMR studies on clay suspensions, we have shown how the orientation of interfacial molecules is affected by the clay structure1, by the nature of counterions 2, or by the composition of the liquid phase3. These results have been mainly obtained from the analysis of residual quadrupolar splittings of nuclei from interfacial species. In this work, we report our studies on a clay montmorillonite suspended in aqueous solutions of non ionic polymers. The polymer perturbs the structure within the interfacial region as deduced from the variations of the splittings of water quadrupolar nuclei and of sodium-23 relaxation parameters in terms of the polymer concentration. Proton self-diffusion coefficients and carbon-13 relaxation times are measured to describe the influence of the clay on the polymer mobility. The dependence of the polymer nature on these parameters is also investigated.     

A quantitation problem in the open tubular gas chromatography of fatty acid esters from cod liver lipids

Methyl esters of fatty acids of marine origin contain large amounts of highly unsaturated long-chain fatty acids. It is shown that, although esters of saturated and monounsaturated fatty acids can be quantitatively analyzed on open tubular columns with a flame ionization detector there are serious losses of the long-chain highly unsaturated fatty acids of marine oils on the column. Through comparison of chain-length composition and iidine value some correction factors are suggested for the highly unsaturated fatty acids which permit reasonably accurate analyses.     

Zur Berechnung von Wirbelkernhalbmessern in rotationssymmetrischen Drallströmungen

Zusammenfassung Drei der bedeutendsten Verfahren zum Berechnen des Wirbelkernhalbmessers in rotationssymmetrischen Drallstr?mungen werden miteinander verglichen. Zwar liegt jedem dieser Verfahren eine Energieberechnung zugrunde; die Ergebnisse unterscheiden sich jedoch erheblich voneinander. Es wird die Ursache jener Abweichungen untersucht und festgestellt, da? das von K. Bammert vorgeschlagene Verfahren nur mit Berücksichtigung der Volumflu?verteilung die gleichen Ergebnisse wie die Berechnungsverfahren von E. Meldau und M. Strscheletzky liefert. Ferner geht aus der Untersuchung die Bedeutung der Axialgeschwindigkeitsverteilung hervor. Die Verwendbarkeit dieser Verfahren bleibt dadurch auf jene F?lle beschr?nkt, in denen der Drall und die Axialgeschwindigkeit in der betrachteten achsnormalen Ebene konstant sind.     

Performance index sensitivity of the constrained minimum variance input-output estimator

After some general considerations, the variations of the performance index under different error conditions are investigated. The specific effects discussed are the misestimation of the process parameters and that of the zero-shift noise covariance matrix and also the non-zero mean of the noise. The theoretical considerations are substantiated by simulation results.