Zur natürlichen Auflagerung von Platten

Die übliche Benutzung von fehlerempfindlichen Programmsystemen erfordert zunehmend die Bereitstellung einfacher Überschlagsformeln zur Ergebniskontrolle. Flächentragwerke z. B. Platten zeigen oft die Neigung, Minimalflächen auszubilden. Das gilt auch für die Auflagerungen, so dass z. B. rechtwinklige Auflagerränder durch statisch günstigere Kreis‐ oder elliptische Ränder virtuell verändert werden. The natural support of plates. The usual use of sensitive incorrect program codes requires an increasing provision of simple estimation formulas to control the results. Plane load bearing structures often want to erect minimum areas. This is also valid for their supports, where rectangular lines may alter virtual to more convenient circular or elliptic edges.     

Fluorine depth profiling by high-resolution 1D magnetic resonance imaging

High-resolution magnetic resonance imaging (MRI) has been used, for the first time, to measure fluorine concentration profiles with a high spatial resolution (5 μm) along the full film depth of fluorinated polyurethane films. The MRI fluorine profiles were consistent with the results obtained by X-ray photoelectron spectroscopy (XPS) in combination with microtoming. MRI is a nondestructive and potentially quantitative technique for probing the spatial distribution of small quantities of fluorine in coatings and multi-layered systems.     

Sintering of nano-sized titania particles and the effect of chlorine impurities

The consolidation behaviour of two titania nanopowders with comparable specific surface area is reported in this study. Surface impurities were identified as a key element influencing the sintering behaviour of titania nanopowders. Raw materials for the synthesis processes of the nanopowders were titanium tetrachloride (TiCl₄) and titanium tetraisopropoxide (TTIP), respectively. Particle properties, densification and sintering behaviour were investigated by several techniques (SEM, TEM, XRD, MIP and dilatometry). Phase transformation and densification of the nanopowder, prepared from TiCl₄, started at lower temperature compared to the powder synthesized from TTIP. However, a drastic grain growth occurred during the final stage of sintering of the TiCl₄ synthesized nanopowder. Chlorine impurities were identified by STA-MS. After purification of this nanopowder, the chlorine was effectively removed from particle surfaces and grain growth was reduced.     

Crystal Structure of Orthorhombic Zirconia in Partially Stabilized Zirconia

A neutron powder diffraction investigation confirms that, in tough magnesiapartially-stabilized zirconia cooled to 30 K, most of the tetragonal zirconia transforms to an orthorhombic phase. This phase is retained on heating to room temperature; the lattice parameters at 295 K are a = 0.5068, b = 0.5260, and c = 0.5077 nm. The room-temperature crystal structure (space group Pbc2₁) is determined by multiphase Rietveld refinement from the neutron diffraction pattern. This orthorhombic structure is compared with the parent tetragonal structure and with the structure of monoclinic zirconia, which it closely resembles.     

Microcavity Formation in Alumina Using Ti Templates II: Mechanism and Kinetics

In part I of this work, it was found that titanium (Ti) wire encapsulated within mechanically milled alumina powder and sintered at 1350°C forms potentially useful microcavities due to the consolidation of Kirkendall porosity. Here a series of samples sintered at 1350°C in the range 0–24 h has shown the remarkable way in which these cavities form. The cavity has already started in samples quenched from the top of the heating ramp (0 min at 1350°C). It is surrounded by a diffusion zone ∼300 μm in diameter, which does not change size throughout the firing process although the contents change markedly. The diffusion zone microstructure is initially complex with phase sequence TiO₂/Al₂O₃/TiO₂+Al₂O₃/Al₂TiO₅. Microstructure evolution may be summarized as outward growth of the cavity accompanied by inward growth of the Al₂TiO₅ resulting in a ∼190-μm-diameter cavity surrounded by a 50-μm-thick layer of Al₂TiO₅. The formation of the cavity and surrounding microstructure is discussed although some features, such as the nucleation of Al₂TiO₅ in the part of the diffusion zone furthest from the Ti source and the ring of Al₂O₃, which persists in between Ti-rich parts of the diffusion zone are still poorly understood.     

Measuring diagnostic agreement.

Diagnostic agreement tests the reliability and concordance of diagnostic systems. The introduction of measures of agreement with reputations for baserate independence (e.g., Yule's Y and Q), and new studies occasioned by the publication of the Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM-IV; American Psychiatric Association, 1994) and the International Classification of Diseases—10 (ICD-10, World Health Organization, 1992) make it necessary to study the relationship of illness baserates to measures of agreement. Testing diagnostic concordance for diagnoses of drug dependence from the third edition of the DSM (American Psychiatric Association, 1980) versus DSM-IV diagnoses of drug dependence under 3 baserate conditions, it was found that Yule's Y and Q proved as vulnerable to differences in baserates as kappa or percent agreement and that specificity covaried with baserate rather than being fixed, as most theoretical discussions assume. The uncritical use of Y and Q, therefore, is likely to lead to optimistic interpretations of agreement. Kappa should be preferred for most purposes, although an adjustment to the computational formulas for Y and Q is presented that can diminish their positive bias. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Möglichkeiten zur Energieeinsparung beim Eindampfen,mit Beispielen aus der Praxis

Possibilities of Energy Saving in Evaporation, with Industrial Examples. In order to render the evaporation process still more economical than up to now the energy consumption or part of the energy consumption of an evaporation plant is covered by waste heat, e. g. by vapour produced in processes proceeding under low vacuum. Mixtures of water vapour and air, e. g. from driers, are also suitable for heating vacuum evaporation plants. Evaporators which shall consume small quantities of steam and cooling water only will be equipped with mechanical vapour compressors. This, however, involves high investment costs.