Effect of surface treatment on segregation of impurities in haematite

Surface segregation of various impurities such as Mg, Si, Ca, Al and Cr were determined for the haematite phase (Fe₂O₃) annealed in two different gas compositions involving (1) air at 1173 K, and (2) a gas mixture containing sulphur at 773 K. The objective of work was to establish the effect of the gas-phase composition on segregation of lattice defects. The near-surface segregation profiles of the impurities were determined by secondary ion mass spectrometry. The depth profile analysis was made by sputtering using an Ar⁺ primary beam of energy 30 keV. The surface charge was neutralized by an electron gun. It was found that annealing Fe₂O₃ under a gas phase containing sulphur resulted in the formation of an Fe(SO₄)₃ surface layer. It was observed that the two surface treatment procedures applied (both with and without sulphur) result in Mg enrichment in the near-surface region of Fe₂O₃. Si and Ca exhibit an enrichment and impoverishment after the surface treatments 1 and 2, respectively. Finally, the near-surface layer is impoverished in Cr and Al after both types of surface treatment. Experimental results are discussed in terms of segregation driving forces of the respective elements and the possible effect of sulphur on the gas-solid heterogeneous kinetics.     

Work-oriented development of knowledge-based systems: a case for multiple perspectives

System development is strongly influenced by the perspectives used by system developers. Current development methods for knowledge-based systems are based on an information processing perspectives of experts and users which has been criticized by a number of researchers. The paper argues that work-oriented development of knowledge-based systems requires the parallel use of multiple perspectives (including the information processing perspective), and that the use of any single perspective is potentially dangerous. As an example of the importance of using multiple perspectives, thepaper presents the situated action perspective, and shows how it complements the information processing perspective.     

Materialien für die Brillenbeschichtung in Aufdampfanlagen

Materials for ophthalmic coatings in PVD – coating equipments In our days we cannot have an isolated view only at the coatings for organic lenses. We need to analyse the interaction of substrates, hardcoats and layerdesigns to deliver a longlife – quality of the complete complex “eyeglases”. Special in the field of organic substrates we could observe in the last years an enormous change. The push to deliver more and more thinner and lighter lenses, produces materials with higher indices. The result from this problem is not the adaptation of the antireflection desin at the substrate index but the adaption at the mechanical and thermal properties of these substrates. The caoting labs influence at the complete system is more or less reduced only by the antireflection system. The substrate‐ and hardcoat material could be influenced only by the “world player” for ophthalmic systems. All the small and middle size coating labs worldwide must buy the substrates‐ and the hardcoat materials and have to accept the quality. The only exertion of influence is in the selection of film materials for the AR‐coating and the process technology. The right choise of coating material in quality, form and costs is crucial for a high quality AR‐ coating. A multitude of factors must be considered for the selection of the adequate material.     

The impact of the EU ETS on the sectoral innovation system for power generation technologies – Findings for Germany

This paper provides an overview of early changes in the sectoral innovation system for power generation technologies which have been triggered by the European Emission Trading System (EU ETS). Based on a broad definition of the sector, our research analyses the impact of the EU ETS on the four building blocks ‘knowledge and technologies’, ‘actors and networks’, ‘institutions’, and ‘demand’ by combining two streams of literature, namely systems of innovation and environmental economics. Our analysis for Germany is based on 42 exploratory interviews with experts in the field of the EU ETS, the power sector, and technological innovation. We find that the EU ETS mainly affects the rate and direction of technological change of power generation technologies within the large-scale, coal-based power generation technological regime, to which carbon capture technologies are added as a new technological trajectory. While this impact can be interpreted as the defensive behaviour of incumbents, the observed changes should not be underestimated. We argue that the EU ETS’ impact on corporate CO₂ culture and routines may prepare the ground for the transition to a low-carbon sectoral innovation system for power generation technologies.     

Kompetenzzentrum Wasserkraft

AktuellKelag und Rwe

Kompetenzzentrum Wasserkraft     

Acute therapy of episodic and chronic cluster headache with sumatriptan s.c. Results of a one-year long-term study

Breast cancer is the commonest malignancy to affect women. The malignant process may present clinicians with problems in establishing the diagnosis expeditiously, accurately staging the disease and assessing tumour response to primary systemic chemotherapy. Considerable recent interest has focused on the application of imaging techniques that utilize tumour-specific gamma-ray-emitting radiopharmaceuticals to resolve these problems. The wide availability of gamma camera systems makes single photon-imaging techniques, using radiopharmaceuticals incorporating conventional isotopes, attractive options. However, results concerning the detection of the primary breast cancer and the staging of axillary lymph nodes suggest that these techniques would appear to offer no significant advantages, when compared with those obtained using standard diagnostic methods. Dual gamma-ray-emission imaging by positron emission tomography (PET) may offer an alternative solution. Studies performed show that PET can accurately detect primary breast cancers, stage locoregional lymph nodes and visualize distant tumour metastases. Furthermore, PET may be able to monitor early tumour response to chemotherapy agents. It would appear, therefore, that dual gamma emission might have an important role to play in the management of patients with breast cancer.     

Age profile,personnel costs and scientific productivity at the University of Vienna

This study analyzes the age profile of scientific employees and its relation to personnel costs and scientific productivity within eight faculties at the University of Vienna. The age demography can overall be divided into two main categories: Category one faculties represent an increased number of younger aged researchers (Catholic-, Protestant Theology, Law, Economics, Information Sciences, and Medicine), category two faculties show an increased number of older aged researchers (Social Sciences, Humanities, and Science). In addition, it can be demonstrated that the personnel costs for full professors are higher within four faculties (Catholic-, Protestant Theology, Law, and Economics and Information Sciences). Inevitably, this leads to savings for habilitated and non- habilitated researchers at these faculties. The faculty of Medicine represents a well-balanced use of personnel costs. Three faculties (Social Sciences, Humanities, and Sciences) have to pay dramatically more for their older aged habilitated and non-habilitated personnel. For the entire university and two faculties, Medicine and Humanities, a positive and significant relationship between age and the average weekly teaching performance is shown. This study suggests that institutions with a high percentage of older researchers, mainly in the categories of habilitated and non- habilitated personnel, must change their policy to become more flexible and attractive for new talented young people. Due to the fact, that this cannot only be realized through the introduction of new laws, each faculty must establish a scientific plan combined with reorganizations of the personnel structure and personnel costs. This revised version was published online in August 2006 with corrections to the Cover Date.     

Analogy for the maximum obtainable colouration between electrochromic, gasochromic, and electrocolouration in DC-sputtered thin WO3−y films

Tungsten oxide films with varied substoichiometry were deposited by reactive DC-sputtering from a W target at different oxygen partial pressures. The inherent maximum achievable electrochemical colouration and electrocolouration were found to be dependent on the oxygen content and consequently on the film substoichiometry. These results were related to those obtained in a previous study by colouration with hydrogen spillover from a catalyst (gasochromic colouration) of films fabricated in the same way. A clear analogy among the colouration by the three different techniques appeared.