Atomistic model structure of the Ge(1 0 0)–GeO2 interface

An atomistic model of the Ge–GeO₂ interface has been generated through first-principle methods based on density functional theory. The interface model consists of amorphous GeO₂ connected to crystalline Ge through a substoichiometric oxide region showing regular structural parameters. Structural and electronic properties are compared to available experimental data and studied as they evolve across the Ge–GeO₂ interface.     

Lung function among black and white children

Racial differences in ventilatory lung function were evaluated in a community study of 393 children (158 blacks, 235 whites). Mean forced vital capacity was 18 per cent larger in nonsmoking white males than in nonsmoking black males, and 11 per cent larger in nonsmoking white females than in nonsmoking black females. Similar differences were observed for the 1-sec forced expiratory volume and for the maximal expiratory flow at 50 per cent of the vital capacity. However, when adjusted for lung size (on the basis of forced vital capacity), 1-sec forced expiratory volume and maximal expiratory flow at 50 per cent of the forced vital capacity were larger in the black children compared to the white children. Lung function prediction equations based on race, sex, age, height and weight are presented for healthy nonsmoking children; these allow for an evaluation of normal lung function in both black and white children.     

Test cells for the investigation of battery reactions at high internal pressures

Beginning with a construction based on a C-size (LR-14) battery container (can), encased in a strong PMMA-support and fitted with a removable cell top equipped with a manometer and a gas-outlet valve, a second and, finally, a more refined third generation cell was developed. The final (3rd generation) design provides additional options for experimental work. For example, the system can be flushed with inert gas; a regulating gas-flow valve has been fitted to feed precisely a gas chromatograph with the gaseous reaction products and a reference electrode to measure anode and cathode potentials individually has also been incorporated. Since AA cells (LR-6) are the dominant monocell battery size, test cells of the second generation were fitted with an adapter to accomodate either a C- or an AA-size. However, the most recent system was designed exclusively for AA-sized cans. The different cell designs are described and examples of their practical application (e.g., overcharge experiments) are given.     

Democratic design experiments: between parliament and laboratory

For more than four decades, participatory design has provided exemplars and concepts for understanding the democratic potential of design participation. Despite important impacts on design methodology, participatory design has, however, been stuck in a marginal position as it has wrestled with what has been performed and accomplished in participatory practices. In this article, we discuss how participatory design may be reinvigorated as a design research programme for democratic design experiments in the light of the decentring of human-centredness and the foregrounding of collaborative representational practices offered by the ANT tradition in the tension between a parliament of things and a laboratory of circulating references.     

Effective thermal conductivity of vacuum insulation panels

Vacuum insulation panels (VIPs) with evacuated fumed silica as the core material and different barrier envelopes were subjected to a series of tests in a guarded hot plate apparatus. The process was conducted to determine thermal conductivity at the centre-of-panel and the edge effect, i.e. the linear thermal transmittance due to the thermal conductivity of the barrier envelope, which is many orders of magnitude higher than that of the evacuated fumed silica. Numerical simulations using a two-dimensional model were carried out in parallel and compared with measured results. In a further step, the influences of different parameters such as panel size, metal layers in the barrier envelope and the shape of the joint between two adjacent VIPs were quantified. Based on these findings, an effective thermal conductivity can be attributed to a system of VIPs. Investigations were performed within the framework of an international research programme of the IEA, Annex 39 ‘High Performance Thermal Insulation in Buildings and Building Systems’, Subtask B.     

Flexible and efficient profiling with aspect‐oriented programming

Many profilers for virtual execution environments, such as the Java virtual machine (JVM), are implemented with low‐level bytecode instrumentation techniques, which is tedious, error‐prone, and complicates maintenance and extension of the tools. In order to reduce the development time and cost, we promote building profilers for the JVM using high‐level aspect‐oriented programming (AOP). We show that the use of aspects yields concise profilers that are easy to develop, extend, and maintain, because low‐level instrumentation details are hidden from the tool developer. In order to build efficient profilers, we introduce inter‐advice communication, an extension to common AOP languages that enables efficient data passing between advices that are woven into the same method using local variables. We illustrate our approach with two case studies. First, we show that an existing, instrumentation‐based tool for listener latency profiling can be easily recast as an aspect. Second, we present an aspect for comprehensive calling context profiling. In order to reduce profiling overhead, our aspect parallelizes application execution and profile creation, resulting in a speedup of 110% on a machine with more than two cores, compared with a primitive, non‐parallel approach. Copyright © 2011 John Wiley & Sons, Ltd.