Generic fault isolation concept for telecommunication systems in access networks

This paper presents an approach for a generic fault isolation (FI) concept for telecommunication systems in the access network area. Based on a distributed processor architecture, a universal software structure for a FI unit is proposed. It is able to isolate faults, field replaceable units and is easily portable to different hardware platforms. The reusability of the FI unit is achieved by separating the software into generic control functionality and fully hardware-dependent software parts, i.e. user configurable tables and hardware-dependent control routines. The implementation of the concept is discussed in a ‘fiber to the building’-system which has already entered into mass-production. © 1997 John Wiley & Sons, Ltd.     

The Internal Structure of the Velvet Worm Projectile Slime: A Small-Angle Scattering Study

For prey capture and defense, velvet worms eject an adhesive slime which has been established as a model system for recyclable complex liquids. Triggered by mechanical agitation, the liquid bio-adhesive rapidly transitions into solid fibers. In order to understand this mechanoresponsive behavior, here, the nanostructural organization of slime components are studied using small-angle scattering with neutrons and X-rays. The scattering intensities are successfully described with a three-component model accounting for proteins of two dominant molecular weight fractions and nanoscale globules. In contrast to the previous assumption that high molecular weight proteins—the presumed building blocks of the fiber core—are contained in the nanoglobules, it is found that the majority of slime proteins exist freely in solution. Only less than 10% of the slime proteins are contained in the nanoglobules, necessitating a reassessment of their function in fiber formation. Comparing scattering data of slime re-hydrated with light and heavy water reveals that the majority of lipids in slime are contained in the nanoglobules with homogeneous distribution. Vibrating mechanical impact under exclusion of air neither leads to formation of fibers nor alters the bulk structure of slime significantly, suggesting that interfacial phenomena and directional shearing are required for fiber formation.     

Pumping stations for today's steel degassing requirements

This article focuses on the vacuum equipment used in vacuum degassing (VD) and vacuum oxygen decarburization (VOD) processes. Despite harsh process conditions caused by outgassing and the process gases themselves, there are various pumping principles and designs of vacuum pumps that can be used. Through clever pump selection there is an opportunity to realize substantial energy and operating resource savings on the vacuum pumping side. Last but not least, a new pump series will be presented that further contributes to cost reduction through higher efficiency.     

A Facile Molecular Approach to Amorphous Nickel Pnictides and Their Reconstruction to Crystalline Potassium-Intercalated γ-NiOOHx Enabling High-Performance Electrocatalytic Water Oxidation and Selective Oxidation of 5-Hydroxymethylfurfural

The low-temperature molecular precursor approach can be beneficial to conventional solid-state methods, which require high temperatures and lead to relatively large crystalline particles. Herein, a novel, single-step, room-temperature preparation of amorphous nickel pnictide (NiE; EP, As) nanomaterials is reported, starting from NaOCE(dioxane)_n and NiBr₂(thf)_1.5. During application for the oxygen evolution reaction (OER), the pnictide anions leach, and both materials fully reconstruct into nickel(III/IV) oxide phases (similar to γ-NiOOH) comprising edge-sharing (NiO₆) layers with intercalated potassium ions and a d-spacing of 7.27 Å. Remarkably, the intercalated γ-NiOOH_x phases are nanocrystalline, unlike the amorphous nickel pnictide precatalysts. This unconventional reconstruction is fast and complete, which is ascribed to the amorphous nature of the nanostructured NiE precatalysts. The obtained γ-NiOOH_x can effectively catalyse the OER for 100 h at a high current density (400 mA cm⁻²) and achieves outstandingly high current densities (>600 mA cm⁻²) for the selective, value-added oxidation of 5-hydroxymethylfurfural (HMF). The NiP-derived γ-NiOOH_x shows a higher activity for both processes due to more available active sites. It is anticipated that the herein developed, effective, room-temperature molecular synthesis of amorphous nickel pnictide nanomaterials can be applied to other functional transition-metal pnictides.     

Neue Regelungen für den Grund‐ und Tunnelbau im Bundesfernstraßenbereich – Teil II: Tunnelbau

New guidelines for foundation and tunnel engineering in the field of German Federal Highways, part II – tunnel engineering. A general overview about the structure of the regulations for civil engineering works on the federal highways (ZTV‐ING) and the new regulations for foundation works was already given in the issue 12/2007 of Bautechnik [8]. The modified and new developed regulations for road tunnel constructions in Germany are presented in this issue. Special focus will be laid on the new regulations for mechanised shield excavation methods and on tunnel sealing systems.     

An Intriguing Array of Extrudate Patterns in Long-Chain Branched Polymers During Extrusion

The present study highlights a range of surface and volume extrudate patterns that can be detected during the extrusion flow of long-chain branched polymers. Thus, four linear low-density polyethylenes (LDPEs) have been extruded using a single-screw extruder coupled to an inline optical imaging system. The selected LDPEs are selected to outline the influence of molecular weight and long-chain branching on the types of melt flow extrusion instabilities (MFEI). Through the inline imaging system, space–time diagrams are constructed and analyzed via Fourier-transformation using a custom moving window procedure. Based on the number of characteristic frequencies, peak broadness, and whether they are surface or volume distortions, three main MFEI types, distinct from those typically observed in linear and short-chain branched polymers, are identified. The higher molecular weight, low long-chain branching LDPEs exhibited all three instability types, including a special type volume instability. Independently of the molecular weight, higher long-chain branching appeared to have a stabilizing effect on the transition sequences by suppressing volume extrudate distortions or limiting surface patters to a form of weak intensity type.     

Nanoscale Control of the Surface Functionality of Polymeric 2D Materials

Typically, 2D nanosheets have a homogeneous surface, making them a major challenge to structure. This study proposes a novel concept of 2D organic nanosheets with a heterogeneously functionalized surface. This work achieves this by consecutively crystallizing two precisely synthesized polymers with different functional groups in the polymer backbone in a two-step process. First, the core platelet is formed and then the second polymer is crystallized around it. As a result, the central area of the platelets has a different surface functionality than the periphery. This concept offers two advantages: the resulting polymeric 2D platelets are stable in dispersion, which simplifies further processing and makes both crystal surfaces accessible for subsequent functionalization. Additionally, a wide variety of polymers can be used, making the process and the choice of surface functionalization very flexible.