Plasma Etching of Nano-Structured Precursor-Derived Ceramic Composites

This paper reports on the analysis of the microstructure of precursor-derived ceramics by plasma etching and field emission scanning electron microscopy. By applying this technique, the nano-crystals in Si–C–N-based ceramics and composites can be clearly observed without difficulty.     

Pubic osteotomy in obturator gliding hernia

Hernias of the obturator foramen are rare. They are described mostly in elderly female patients in poor health. Often the correct diagnosis is stumbled upon as a result of surprising intraoperative findings. Surgical therapy is indicated often by the clinical symptoms of an incarcerated hernia. Herniation of the entire urinary bladder with hemorrhagic infarction has never been described before. For an anatomical reduction of the hernia it was necessary to resect the superior pubic ramus. For plastic reconstruction a marlex mesh was used.     

Distinctions of unmitigated communion from communion: self-neglect and overinvolvement with others

The authors sought to distinguish unmitigated communion, a focus on others to the exclusion of the self, from communion, a positive caring orientation toward others. Across four studies, the authors showed that unmitigated communion and communion are correlated, but that unmitigated communion is distinct from communion in terms of a negative view of the self, turning to others for self-evaluative information, and psychological distress. They also sought to explain the relation of unmitigated communion to distress. It was found that unmitigated communion individuals' reliance on others for self-esteem leads to overinvolvement with others and a neglect of the self, which, in turn, account for the relation of unmitigated communion to distress.     

Inertial impaction of aerosol particles on single and multiple spherical targets

Inertial deposition of aerosol droplets (diameter: 1–14 μm) on steel spheres (diameter: 3–9 mm) was investigated. Air velocity was varied between 7 and 28 m/s (corresponding sphere Reynolds numbers: 1400–17000). The impaction on single spheres as well as that on linear arrays of eight spheres was measured. Theoretical results, based on potential flow investigations were verified by single sphere experiments. Of special interest was the range of lower Stokes numbers, where the theoretically predicted limit of deposition cannot be verified. The experiments on sphere arrays were for the first time performed in the low Stokes number range. Deposition on the leading sphere, relative to that on the shielded spheres, exhibits a maximum in the high Stokes number range, but this changes drastically in the low Stokes number range. Here, maximum deposition can be found on the shielded spheres while the leading sphere shows a markedly lower deposition.     

Consolidation phenomena in laser and powder-bed based layered manufacturing

Layered manufacturing (LM) is gaining ground for manufacturing prototypes (RP), tools (RT) and functional end products (RM). Laser and powder bed based manufacturing (i.e. selective laser sintering/melting or its variants) holds a special place within the variety of LM processes: no other LM techniques allow processing polymers, metals, ceramics as well as many types of composites. To do so, however, quite some different powder consolidation mechanisms are invoked: solid state sintering, liquid phase sintering, partial melting, full melting, chemical binding, etc. The paper describes which type of laser-induced consolidation can be applied to what type of material. It tries to understand the underlying physical mechanisms and the interaction with the material properties. The paper demonstrates that, although SLS/SLM can process polymers, metals, ceramics and composites, quite some limitations and problems cause the palette of applicable materials still to be limited. There is still a long way to go in tuning the processes and materials in order to enlarge the applicability of LM. This is not surprising if one compares it to the decades of R&D work devoted to tuning processes and materials for hot or cold forming, metal cutting (e.g. development of free machining steels), casting and injection moulding (including powder injection moulding: MIM, CIM, etc.).