Elektrolytkoagulation schwach solvatisierter Sole und Elektrolytaktivität,II

Ohne Zusammenfassung     

The influence of different evaluation techniques on the results of interlaboratory comparisons

The influence of different evaluation techniques on the results of an interlaboratory comparison for the determination of nutrients in ground- and surface water was investigated. The outlier-test procedure was found to influence the interlaboratory standard deviations (SDs), but not the averages. It was shown that even small differences in the numbers of outliers detected can change the SD severely. Comparing the outlier-test procedures of Hampel, Grubbs and Graf-Henning, it was found that Hampel's test detected the most outliers, thus generally resulting in smaller SDs between interlaboratory comparisons. The Graf-Henning test detected the fewest outliers and its application resulted in the highest SDs of the three test procedures investigated. The comparison of different summarising indices, namely the rescaled sum of z-scores, average of absolute z-scores and average deviation showed no comparability. Possibilities to improve the comparability of interlaboratory comparisons and to minimise misunderstandings are suggested.     

Development of reference materials for microbiological analysis

The reliability of reference materials (RMs) depends on properties such as fitness, robustness, commutability, stability and homogeneity. The development of RMs for microbiological analysis is especially challenged through questions around the stabilisation and recovery of viable cells, the dispersion of precise numbers of cells, matrix effects and, when using molecular techniques, the presence of nucleic acids (e.g. DNA) of dead and live target organisms. However, RMs are indispensable tools for quality control in microbiological analysis. The Institute for Reference Materials and Measurements (IRMM), as part of the European Commission, concentrates its efforts on the development of RMs to support the development, implementation and monitoring of EU legislation. A special focus is given to highly precise RMs for presence/absence and enumeration tests in microbiological food and water analysis. Another group of new RMs certified by the IRMM comprise DNA-based materials to control the identity of micro-organisms in qualitative assays. All of these activities serve to improve quality control in microbiological analysis. Presented at ‘BERM-10’, April 2006, Charleston, SC, USA.     

Vibration analysis by means of digital shearography

Digital shearography, also called digital speckle pattern shearing interferometry, is described as a robust measuring method due to its simple optical setup and the relative insensitivity against ambient noise. It has been applied for nondestructive testing and strain measuring. This paper explores its possibilities for vibration analysis. The measuring device performing both continuous (time-average method) and stroboscopic illuminations is described. The selection of the illumination mode is made by adjusting a controller and performed simply by a computer. The real-time observation with refreshing reference frame technique and the quantitative evaluation with the phase shift technique are presented. The results show this measuring device is well suited for both qualitative and quantitative vibration analysis.     

Biotechnological production of two new 8,4′-oxynorneolignans by elicitation of Echinacea purpurea cell cultures

Two new 8,4′-oxynorneolignans were produced by elicitation of Echinacea purpurea cell suspension cultures with yeast elicitor. Their structures with an unusual (hydroxy)acetyl group were elucidated by spectroscopic methods including gas chromatography (GC) and electrospray ionization (ESI) mass spectrometry.     

Surface and bulk plasmon coupling observed in reflection electron energy loss spectra

Reflection electron energy loss spectra have been measured for a semiconductor and some metals (Si, Cu, Ag and Au). A novel procedure is presented to rigorously decompose the spectra into contributions corresponding to surface and volume excitations. The resulting distributions of energy losses in an individual surface loss are in good agreement with theory. In particular, the begrenzungs effect occurring at the boundary of a solid state plasma, i.e. the reduction of the intensity of bulk modes due to the coupling with surface modes, can be clearly observed in the retrieved energy loss distribution.