Anwendungsorientierung im Informatikstudium

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Forum The built environment through the cultural–architectural lens

The Building Research & Information special issue ‘Developing Theories on the Built Environment’ (36(3) 2008) raises the question of whether there could be a common framework to combine a wide range of interests and provide insightful answers. This commentary explores the significance of cultural contexts for theories on the built environment. Deficiencies in both architectural theory and history have left cultural associations and values inarticulated. Increasingly, architectural theory and history have become marginalized in the widening debate about the built environment as their focus has become too limited and separated from everyday and urgent needs. The cultural ‘footprint’ remains the strongest force and determines patterns of behaviour and expectations. It is argued that a cultural lens is the primary key in providing both insight into an ideal and consciousness of (intellectual and practical) habits influencing our actions. In order to grasp the complexity of the built environment and provide a useful model for altering our collective actions, it is vital to study the transformational chains, for example, from the cultural to the ecological.

Ce numéro spécial de Building Research & Information consacré aux théories de développement du milieu bâti (volume 36(3), 2008) pose la question de la création possible d'un cadre commun capable de combiner une grande palette d'intérêts et de fournir des réponses intuitives. Cet article analyse le sens des contextes culturels de théories relatives au milieu bâti. Les lacunes que l'on constate dans la théorie et dans l'histoire de l'architecture n'ont pas permis d'expliquer les valeurs et les associations culturelles. De plus en plus, la théorie et l'histoire de l'architecture ont été marginalisées dans le débat qui s'élargit sur le milieu bâti car leurs points d'intérêt sont devenus trop limités et à l'écart des besoins quotidiens et urgents. L'empreinte culturelle demeure la force la plus importante et détermine les tendances de comportement et des attentes. On prétend qu'une loupe grossissante de la culture est la clef principale pour fournir à la fois un idéal et une conscience des habitudes (intellectuelles et pratiques) ayant une influence sur nos actions. Pour saisir la complexité du milieu bâti et fournir un modèle utile en vue de modifier nos actions collectives, il est essentiel d'étudier les chaînes transformationnelles, par exemple, de la culture à l'écologie.

Mots clés: théorie de l'architecture, milieu bâti, cadre conceptuel, sagesse pratique, formulation de théories, elaboration de théories     

Design von pulverförmigen und granularen Waschmitteln

In the last fifty years, powder and granular detergents have been significantly improved in performance and ecology: more concentrated (less chemicals), biodegradable surfactants, no phosphates, reduced water and energy consumption. The use of optimized enzymes and bleaching boosters enables lowered wash temperatures and the removal of natural stains. The production of solid detergents runs either in spray towers without and with compaction step, or in a non‐tower agglomeration plant. The latest generation of granulation with an integrated mill for simultaneous drying and grinding allows the production of spherical particles, which can be adjusted (small or large, heavy or light). Future formulations will enable lower washing temperatures.     

Dynamic behavior of nanometer-scale amorphous intergranular film in silicon nitride by in situ high-resolution transmission electron microscopy

We report about the dynamic behavior of a nanometer-scale amorphous intergranular film (IGF) in a Si₃N₄ ceramic by an in situ heating experiment in a high-resolution transmission electron microscopy (HRTEM). During the experiment the IGF gradually vanishes at 820 °C accompanied by the formation of crystal planes within the IGF. The IGF reappears after cooling back to room temperature. The results cannot be explained within the framework of a force balance model. We argue that the dynamic behavior of the IGF in our experiment originates from the open system observed.     

Oxidation of Silicon Carbide Fibers During Static Fatigue in Air at Intermediate Temperatures

The static fatigue of SiC-based fiber bundles and single fibers has been examined in previous papers, with emphasis placed on the analysis of the stress–rupture time data, and on the modelling of delayed failure from slow crack growth. The present paper investigates the oxidation of the fibers during static fatigue, at temperatures in the intermediate temperature range (500°–800°C). Two oxidation-induced phenomena have been evidenced: the formation of a thin silica film at the surface of fibers and the delayed failure of fiber bundles and single filaments. The stress–rupture time data are interpreted with respect to the chemical and structural characteristics of fibers, and to the oxide film growth rate. The structural analysis of the fibers was carried out using scanning electron microscopy and Auger electron spectroscopy. Delayed failure was found to result from slow crack propagation from surface defects, as a result of the consumption of the free carbon at grain boundaries and the local stresses induced by the SiC→SiO₂ transformation at the crack tip. The respective contributions of these phenomena to static fatigue are discussed.     

Sustainability evaluation of decentralized electricity generation

Decentralized power generation is gaining significance in liberalized electricity markets. An increasing decentralization of power supply is expected to make a particular contribution to climate protection. This article investigates the advantages and disadvantages of decentralized electricity generation according to the overall concept of sustainable development. On the basis of a hierarchically structured set of sustainability criteria, four future scenarios for Germany are assessed, all of which describe different concepts of electricity supply in the context of the corresponding social and economic developments. The scenarios are developed in an explorative way according to the scenario method and the sustainability criteria are established by a discursive method with societal actors. The evaluation is carried out by scientific experts. By applying an expanded analytic hierarchy process (AHP), a multicriteria evaluation is conducted that identifies dissent among the experts. The results demonstrate that decentralized electricity generation can contribute to climate protection. The extent to which it simultaneously guarantees security of supply is still a matter of controversy. However, experts agree that technical and economic boundary conditions are of major importance in this field. In the final section, the article discusses the method employed here as well as implications for future decentralized energy supply.     

The TTA's Approach to Resilience after Transient Upsets

The Time-Triggered Architecture, as architecture for safety-critical real-time applications, incorporates fault-tolerance mechanisms to ensure correct system operation despite failures. The primary fault hypothesis of the TTA claims to tolerate either the arbitrary failure of any one of its nodes or the passively arbitrary failure of any one of its communication channels. To cover these failure modes, active redundancy techniques are used, which basically means that nodes and channels are physically replicated. The primary fault hypothesis, is, however, not strong enough for certain applications that have to tolerate transient upsets of multiple, possibly all, components in the system. Such a transient upset of the system may break up the synchrony of the nodes and leave disjoined sets of nodes synchronized to each other while the overall synchronization is lost. Although the TTA provides a clique avoidance algorithm that is able to correct a wide class of such multiple transient failures, a stronger algorithm is needed for full coverage. In this paper we discuss a secondary fault hypothesis for the TTA that addresses the transient upset of multiple components and present a new clique resolving algorithm based on the TTA's integrated diagnosis and startup service. This paper is a revised version of Steiner et al. (2003). This work has been funded by the European Project DECOS (Project number: IST-511764). Michael Paulitsch is currently affiliated with Honeywell International.