Evening office lighting – visual comfort vs. energy efficiency vs. performance?

During the study presented in this article, we compared two highly energy-efficient lighting scenarios for evening office lighting (i.e. electric lighting that is typically used for approxiamately 2 h in the evening). The first of these lighting scenarios (referred to as “Reference”-scenario, Lighting Power Density or LPD of 4.5 W/m²) has been successfully in use in many office rooms of the Solar Energy and Building Physics Laboratory’s experimental building, located on the campus of the Swiss Federal Institute of Technology in Lausanne, for several years. The second lighting scenario (referred to as “Test”-scenario, Lighting Power Density of 3.9 W/m²) is more energy-efficient, creates higher workplane illuminances but leads to an increased risk of discomfort glare. The aim of this study was to meticulously compare the two lighting scenarios in order to find a lighting solution for evening office lighting that offers an optimal trade-off between energy-efficiency, visual comfort and visual performance.     

Developing light metal components

One country where there has been intensive development of light metal-based building components is the German Democratic Republic. Reviewing this progress, Dr Friedrich, a leading scientist at the Institute for Industrial Buildings in the Bauakademie, provides some details of the wall and floor units now in common use and the design parameters and practice codes which have been established.     

Ärztliche Schweigepflicht bei Kindeswohlgefährdung

Definition of the problem Medical confidentiality, which is one of the main pillars of medical ethics, has taken a decisive role in the latest discussions about the improvement of child protection laws. Inexplicit and plurivalent arrangements and procedures of how to legally handle child abuse cases when persons with legal custody refuse to take further support are seen as an obstacle for effective child protection. Arguments Non-specific legal regulations lead to task uncertainty and hesitation on the side of health care professionals, which can result in the delay or even prevention of necessary actions. Therefore, new laws on the federal level have been passed in order to establish certainty with regard to professional secrecy and in order to foster networking among the actors in the field of child protection. Conclusion The paper analyses and discusses these legal attempts at strengthening child protection. Although some of the federal laws have the potential of clarification, the great number of laws and their explication restricts their impact.     

Analytical current-voltage relations for compact SiGe HBT models.II. Application to practical HBTs and parameter extraction

For pt. I, see ibid., vol. 46, no. 7, p. 1384-93 (1999). The current-voltage relations derived in the first part of the paper for an idealized SiGe HBT are now checked for transistors with more practical doping profiles: nonabrupt pn junctions, Ge gradient in the base, and heterojunction within the collector region. It is shown that the “idealized” model equations can still be applied if the model parameters are adequately chosen. Sufficient agreement with device simulation results is obtained even in the high-current region. This holds not only for the static behavior but also for small-signal parameters, e.g., y₂₁ and y₂₂, which are more sensitive to potential errors. As another result, all the investigated HBT versions show improved characteristics compared with the idealized HBT. An adequate procedure of how to extract the model parameters from measurement or simulation results is presented. Both the device simulator and the model equations have been successfully checked by measurements. The model has been extended by a transit time model to a complete compact model called SIGEM, which has been implemented in a commercial circuit simulator and successfully used for the design of high-speed IC's     

Two-dimensional hierarchies of proper languages of lexicalized FRR-automata

Various syntactical phenomena play an important role when developing grammars for natural languages. Among them are the dependencies (subordination) or valences, which are closely related to the complexity of the word-order of the language considered, and the number and types of categories that are used during the process of syntactic disambiguation. Here we present the freely rewriting restarting automaton (FRR-automaton), which is a variant of the restarting automaton that is tuned towards modeling such phenomena. We study proper languages of deterministic FRR-automata that are (strongly) lexicalized, where we focus on two types of constraints: the number of rewrites per cycle, which models the degree of valences within sentences, and the number of occurrences of auxiliary symbols (categories) in the sentences (words) of the corresponding characteristic language, which models the use of categories during the process of syntactic disambiguation. Based on these constraints we obtain four variants of two-dimensional hierarchies of language classes.     

Oligophenylenevinylenes in Spatially Confined Nanochannels: Monitoring Intermolecular Interactions by UV/Vis and Raman Spectroscopy

Perhydrotriphenylene‐based channel‐forming inclusion compounds (ICs) and thin films made of polyphenylenevinylene (PPV)‐type oligomers with terminal alkoxy groups are investigated and compared in a combined experimental and theoretical approach. Interchromophore interactions and host‐guest interactions are elucidated by UV/Vis and Raman spectroscopy. The impact of the local environment of the chromophore on the optical and photophysical properties is discussed in light of quantum‐chemical calculations. In stark contrast to thin films where preferential side‐by‐side orientation leads to quenching of photoluminescence (PL) via non‐emissive traps, the ICs are found to be attractive materials for opto‐electronic applications: they offer high chromophore concentrations, but at the same time behave as quasi‐isolated entities of tightly packed, well‐oriented objects with high PL quantum yields and the possibility of color tuning.