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.     

Semantic Web Mining: State of the art and future directions

Semantic Web Mining aims at combining the two fast-developing research areas Semantic Web and Web Mining. This survey analyzes the convergence of trends from both areas: More and more researchers are working on improving the results of Web Mining by exploiting semantic structures in the Web, and they make use of Web Mining techniques for building the Semantic Web. Last but not least, these techniques can be used for mining the Semantic Web itself.The Semantic Web is the second-generation WWW, enriched by machine-processable information which supports the user in his tasks. Given the enormous size even of today’s Web, it is impossible to manually enrich all of these resources. Therefore, automated schemes for learning the relevant information are increasingly being used. Web Mining aims at discovering insights about the meaning of Web resources and their usage. Given the primarily syntactical nature of the data being mined, the discovery of meaning is impossible based on these data only. Therefore, formalizations of the semantics of Web sites and navigation behavior are becoming more and more common. Furthermore, mining the Semantic Web itself is another upcoming application. We argue that the two areas Web Mining and Semantic Web need each other to fulfill their goals, but that the full potential of this convergence is not yet realized. This paper gives an overview of where the two areas meet today, and sketches ways of how a closer integration could be profitable.     

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.     

More than modelling and hiding: towards a comprehensive view of Web mining and privacy

Over the last decade, privacy has been widely recognised as one of the major problems of data collections in general and the Web in particular. This concerns specifically data arising from Web usage (such as querying or transacting) and social networking (characterised by rich self-profiling including relational information) and the inferences drawn from them. The data mining community has been very conscious of these issues and has addressed in particular the inference problems through various methods for “privacy-preserving data mining” and “privacy-preserving data publishing”. However, it appears that these approaches by themselves cannot effectively solve the privacy problems posed by mining. We argue that this is due to the underlying notions of privacy and of data mining, both of which are too narrow. Drawing on notions of privacy not only as hiding, but as control and negotiation, as well as on data mining not only as modelling, but as the whole cycle of knowledge discovery, we offer an alternative view. This is intended to be a comprehensive view of the privacy challenges as well as solution approaches along all phases of the knowledge discovery cycle. The paper thus combines a survey with an outline of an agenda for a comprehensive, interdisciplinary view of Web mining and privacy.     

The Inflammatory Profile of Obesity and the Role on Pulmonary Bacterial and Viral Infections

Obesity is a globally increasing health problem, entailing diverse comorbidities such as infectious diseases. An obese weight status has marked effects on lung function that can be attributed to mechanical dysfunctions. Moreover, the alterations of adipocyte-derived signal mediators strongly influence the regulation of inflammation, resulting in chronic low-grade inflammation. Our review summarizes the known effects regarding pulmonary bacterial and viral infections. For this, we discuss model systems that allow mechanistic investigation of the interplay between obesity and lung infections. Overall, obesity gives rise to a higher susceptibility to infectious pathogens, but the pathogenetic process is not clearly defined. Whereas, viral infections often show a more severe course in obese patients, the same patients seem to have a survival benefit during bacterial infections. In particular, we summarize the main mechanical impairments in the pulmonary tract caused by obesity. Moreover, we outline the main secretory changes within the expanded adipose tissue mass, resulting in chronic low-grade inflammation. Finally, we connect these altered host factors to the influence of obesity on the development of lung infection by summarizing observations from clinical and experimental data.     

Synthesizing robust systems

Systems should not only be correct but also robust in the sense that they behave reasonably in unexpected situations. This article addresses synthesis of robust reactive systems from temporal specifications. Existing methods allow arbitrary behavior if assumptions in the specification are violated. To overcome this, we define two robustness notions, combine them, and show how to enforce them in synthesis. The first notion applies to safety properties: If safety assumptions are violated temporarily, we require that the system recovers to normal operation with as few errors as possible. The second notion requires that, if liveness assumptions are violated, as many guarantees as possible should be fulfilled nevertheless. We present a synthesis procedure achieving this for the important class of GR(1) specifications, and establish complexity bounds. We also present an implementation of a special case of robustness, and show experimental results.     

Investigations on the curing of epoxides with phthalic anhydride

The anhydride curing of epoxides was studied by performing copolymerizations of epichlorohydrin, phenyl glycidyl ether (PGE), or bisphenol-A-diglycidyl ether (BADGE) with phthalic anhydride (PSA). As initiators, tertiary amines or ammonium salts were used. In the case of epichlorohydrin, linear polyesters were obtained at 100°C. At higher temperatures (140–160°C), a side reaction of the CH₂Cl group took place which caused branching and partial crosslinking of the polymer. The reaction of phenyl glycidyl ether with phthalic anhydride gave linear, strongly alternating copolymers at temperatures of 120–160°C. Molecular weights (M¯_n) were in the range of 4000–87,000, depending on the purity of the starting materials and the initiator used. The reaction of the diepoxide BADGE with phthalic anhydride yielded highly crosslinked products. Their crosslink densities (which correlate with the glass transition temperature T_g). however, did not show the same dependence on initiator and purity of the starting materials as the molecular weights of the linear polyesters obtained by the “model reaction” of PGE with PSA. Possible reasons for this effect are discussed.