The fracture behaviour of specimens with a notch tip partly in the base metal of strength mis-match welded joints

The relevant parameter for the safe service of a welded structure is the critical crack tip opening displacement (CTOD). This value is dependent on the microstructure present along the front of the fatigue pre-crack, which is also in the same locality where the strength mis-matching has a substantial influence. In the case of a specimen containing a through thickness notch, embedded partly in the heat affected zone and partly in the base metal, the fracture behaviour strongly depends on a portion of the ductile base metal and the size and distribution of the mis-matching factor along the vicinity of the crack front. Therefore, if local brittle zones are located in the process zone the ductile base metal cannot prevent pop-in instability, but it can reduce it to an insignificant level during the fracture toughness testing and it can provide higher critical CTOD values.     

Parametricism: A New Global Style for Architecture and Urban Design

Though parametricism has its roots in the digital animation techniques of the mid-1990s, it has only fully emerged in recent years with the development of advanced parametric design systems. Patrik Schumacher explains why parametricism has become the dominant, single style for avant-garde practice today and why it is particularly suited to large-scale urbanism as exemplified by a series of competition-winning masterplans by Zaha Hadid Architects. Copyright © 2009 John Wiley & Sons, Ltd.     

Stability of NiO membranes on photostructurable glass substrates for micro solid oxide fuel cells

NiO thin films with thicknesses in the range of 100 to 900 nm were deposited by spray pyrolysis onto photostructurable glass substrates and, ultimately, free-standing membranes with diameters of 100, 200 and 300 µm were fabricated using these thin films. The membranes are intended to act as simplified anodes or anode current collectors in micro solid oxide fuel cells (µSOFCs) and their differential pressure and thermal stability were characterized. The membranes tolerated a differential pressure between 13,700 and 158,600 Pa. Smaller membranes showed more pressure tolerance than larger membranes. A membrane diameter of 100 µm and a film thickness of 400-500 nm turned out to be a promising geometry for µSOFC membranes. All membranes survived temperatures higher than the intended operating temperature of µSOFCs (350-600 °C). We attribute the good thermal stability to the match of the thermo-mechanical properties of the substrate and the NiO thin films for the lower temperature regime and the substrate softening at higher temperatures releasing stresses in the thin films. Furthermore, the thermal expansion of the substrate is close to thermal expansion of materials used in SOFCs and circular geometries can be realized using wet etching.     

Anodic oxide nanotube layers on Ti-Ta alloys: Substrate composition, microstructure and self-organization on two-size scales

The present work reports the self-ordered formation of nanotubular oxide layers on Ti-Ta alloys of different compositions (Ti-13Ta, Ti-25Ta, Ti-50Ta, and Ti-80Ta) by anodization in 1 M H₂SO₄ + 0.15 wt.% HF. Depending on the alloy composition, nanoporous or highly ordered nanotube structures can be formed. The homogeneity of the nanotubular surface layers is strongly affected by the microstructure of the alloys. Over a wide composition range the alloys exhibit a two-phase structure, and this results in two distinct tube morphologies formed on the different phases. In particular, on the chemically less stable phase, the top of nanotube layers is etched, which results in a disordered top morphology of the tubes on Ti-13Ta and Ti-25Ta, whereas this effect yields a difference in tube length on the two phases on Ti-50Ta. For the Ti-50Ta alloy, a bimodal self-organization can be observed, i.e. ordered patterns of oxide tubes with two distinct diameters are formed where larger tubes are surrounded by smaller tubes with a regularity that depends on the chemical composition of the two phases.     

Harmonization of renewable electricity feed-in laws: A comment

This comment aims at critically analyzing some of the economic efficiency issues that are raised in the paper by Muñoz et al. [2007. Harmonization of renewable electricity feed-in laws in the European Union. Energy Policy 35, 3104–3114] on the harmonization of feed-in law schemes for renewable electricity in the European Union. We comment on the choice between green certificate systems and feed-in laws, but pay particular attention to the implementation and design of a harmonized feed-in law scheme. In the comment we argue first that the approach suggested by Muñoz et al. tends to downplay many of the practical difficulties in assessing the real costs facing investors in renewable electricity, not the least since the presence of regulatory uncertainty about the marginal costs of renewable electricity may be essential for the choice between different support systems. Concerning the benefit side of renewable electricity promotion, the Muñoz et al. (2007) paper builds on an interpretation of the EU Renewables Directive that provides plenty of room for national priorities and that therefore essentially implies that harmonized support premiums per se are of little value. We argue instead that a harmonized system should primarily address the international spillover effects from renewable electricity promotion, not the least those related to improved security of supply in Europe. There exists then a strong case for disregarding the specific national benefits of renewable electricity production in the design of harmonized support systems, and for instead considering international—perhaps at the start bilateral—policy support coordination based on entirely uniform support levels.     

Wearable augmented virtual reality for enhancing information delivery in high precision defence assembly: an engineering case study

Virtual reality (VR) technology has matured during the past few years to a degree where real industrial applications have become feasible. The work described in this paper involves collaboration between Heriot-Watt University and BAE Systems and aimed to establish the feasibility of using augmented VR to support complex information delivery in high precision defence assembly. Laboratory and field studies were conducted which investigated performance when using augmented VR as compared to conventional methods of information delivery. The results show that augmented VR is comparable to conventional methods of information delivery in terms of latencies and errors but allows less disruption to work and greater mobility. There appear to be no adverse affects on operators from using VR and generally operators are positive towards using VR technology. The feasibility of supporting augmented VR with wearable technology is also demonstrated. The overall results are discussed in terms of further application of VR in industrial settings.

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Nanoparticles as pseudostationary phase in capillary electrochromatography/ESI-MS

A novel technique that uses polymer nanoparticles as pseudostationary phase in capillary electrochromatography with electrospray ionization mass spectrometry detection is described. A continuous full filling technique in which the nanoparticles were suspended in the entire electrolyte volume as well as a conventional partial filling technique is presented. No nanoparticles entered the mass spectrometer, which was fitted with an orthogonal electrospray interface, despite the continuous flow of nanoparticles into the interface. Nanoparticles (average diameter 160 nm) were prepared from methacrylic acid, methyl methacrylate, and trimethylolpropane trimethacrylate by utilizing a precipitation polymerization technique. Salbutamol, nortriptyline, and diphenhydramine were used as analytes. The interaction between analytes and nanoparticles was found to be predominantly ionic.     

A new neural associative memory model

We present a new associative memory model based on the Hamming memory, but where the winner-take-all network part is replaced by a layer of nodes with somewhat complex node functions. This new memory can produce output vectors with individual “don't know” bits. the simulations demonstrate that this memory model works appropriately. © 1992 John Wiley & Sons, Inc.     

Physical-chemical characterization and polymorphism determination of two nimodipine samples deriving from distinct laboratories

Knowing the characteristics of raw materials in pharmaceutical practice is both important and useful. Firstly, evaluating the physical-chemical properties of the substances that will be used must be the primary step for quality control in the pharmacy industry. This work aims at analyzing the physical-chemical characteristics of two nimodipine samples I and II derived from distinct laboratories through thermal analysis (DSC and TG/DTG), HPLC, crystallography, and microscopy. Thermal analysis showed that sample II was more unstable than I. Morphological differences concerning shape, size, and crystallinity of particles were visualized by scanning electron microscopy (SEM) and X-ray powder diffraction. To sum up, the techniques used in this study can be said to have been efficient in the characterization and evaluation of quality control of the raw material.