Characterisation of phase composition, microstructure and microhardness of electroless nickel composite coating co-deposited with SiC on casting aluminium LM24 alloy substrate

Electroless Ni-P (EN) and composite Ni-P-SiC (ENC) coatings were developed on cast aluminium alloy, LM24. The coating phase composition, microstructure and microhardness were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) and microhardness tester, respectively, on as-plated and heat-treated specimens. The original microstructure of the Ni-P matrix is not affected by the inclusion of the hard particles SiC. No formation of Ni-Si phase was observed upto 500°C of heat treatment. The microhardness is increased on incorporation of SiC in Ni-P matrix. The hardening mechanism is the formation of intermetallic phase Ni3P on annealing at elevated temperature. Overall, the composite coating (ENC) was found to be superior as compared to particles free (EN) coating in both as-deposited and heat-treated conditions.

Dynamic modelling of die melt temperature profile in polymer extrusion: Effects of process settings, screw geometry and material

Extrusion is one of the major methods for processing polymeric materials and the thermal homogeneity of the process output is a major concern for manufacture of high quality extruded products. Therefore, accurate process thermal monitoring and control are important for product quality control. However, most industrial extruders use single point thermocouples for the temperature monitoring/control although their measurements are highly affected by the barrel metal wall temperature. Currently, no industrially established thermal profile measurement technique is available. Furthermore, it has been shown that the melt temperature changes considerably with the die radial position and hence point/bulk measurements are not sufficient for monitoring and control of the temperature across the melt flow. The majority of process thermal control methods are based on linear models which are not capable of dealing with process nonlinearities. In this work, the die melt temperature profile of a single screw extruder was monitored by a thermocouple mesh technique. The data obtained was used to develop a novel approach of modelling the extruder die melt temperature profile under dynamic conditions (i.e. for predicting the die melt temperature profile in real-time). These newly proposed models were in good agreement with the measured unseen data. They were then used to explore the effects of process settings, material and screw geometry on the die melt temperature profile. The results showed that the process thermal homogeneity was affected in a complex manner by changing the process settings, screw geometry and material.

Investigation of the temperature homogeneity of die melt flows in polymer extrusion

Polymer extrusion is fundamental to the processing of polymeric materials and melt flow temperature homogeneity is a major factor which influences product quality. Undesirable thermal conditions can cause problems such as melt degradation, dimensional instability, weaknesses in mechanical/optical/geometrical properties, and so forth. It has been revealed that melt temperature varies with time and with radial position across the die. However, the majority of polymer processes use only single-point techniques whose thermal measurements are limited to the single point at which they are fixed. Therefore, it is impossible for such techniques to determine thermal homogeneity across the melt flow. In this work, an extensive investigation was carried out into melt flow thermal behavior of the output of a single extruder with different polymers and screw geometries over a wide range of processing conditions. Melt temperature profiles of the process output were observed using a thermocouple mesh placed in the flow and results confirmed that the melt flow thermal behavior is different at different radial positions. The uniformity of temperature across the melt flow deteriorated considerably with increase in screw rotational speed while it was also shown to be dependent on process settings, screw geometry, and material properties. Moreover, it appears that the effects of the material, machine, and process settings on the quantity and quality of the process output are heavily coupled with each other and this may cause the process to be difficult to predict and variable in nature

Co-tape casting fabrication, field assistant sintering and evaluation of a coke resistant La0.2Sr0.7TiO3-Ni/YSZ functional gradient anode supported solid oxide fuel cell

The ability to directly utilize hydrocarbons and other renewable liquid fuels is one of the most important issues affecting the large scale deployment of solid oxide fuel cells (SOFCs). Herein we designed La_0.2Sr_0.7TiO₃-Ni/YSZ functional gradient anode (FGA) supported SOFCs, prepared with a co-tape casting method and sintered using the field assisted sintering technique (FAST). Through SEM observations, it was confirmed that the FGA structure was achieved and well maintained after the FAST process. Distortion and delamination which usually results after conventional sintering was successfully avoided. The La_0.2Sr_0.7TiO₃-Ni/YSZ FGA supported SOFCs showed a maximum power density of 600mWcm^-2 at 750°C, and was stable for 70h in CH₄. No carbon deposition was detected using Raman spectroscopy. These results confirm the potential coke resistance of La_0.2Sr_0.7TiO₃-Ni/YSZ FGA supported SOFCs.

Walter Heissig, Rüdiger, Schott, Die Heutige Bedeutung Oraler traditionen. IHRE Archivierung, Publikation und index-Erschießung

The book under review is the publication of 28 contributions to a workshop which has tak en place in St. Augustin, near Bonn, in November 1995. This was attended by a large number of proeminent scholars, gathered around the commonly felt concern for the need to preserve “the oral traditions of all kinds” (p. 26). The papers, written in German (11), in English (16) and in French (1), are introduced by the organisers Walter Hessig and Rüdiger Schott in both German and English.

Die Darstellung der Apokalypse in den ersten Werken von Ernst Jünger

Dieser Aufsatz analysiert die Darstellung der apokalyptischen Bilder in zwei frühen Werken von Ernst Jünger mit dem Ziel, ihre Ähnlichkeiten und Unterschiede zu den biblischen Apokalypse-Darstellungen zu zeigen. Untersucht werden das Kriegstagebuch 1914/1918 Ernst Jüngers, ein bislang noch unveröffentlichtes Werk des Autors, und In Stahlgewitten, das aus einer literarischen Reinterpretation der Kriegserlebnisse Ernst Jüngers, die im Kriegstagebuch aufgezeichnet wurden, beruht. Alle direkten oder indirekten Erwähnungen der Apokalypse in den untersuchten Werken beziehen sich lediglich auf die Dimension der Zerstörung, da der Autor vor allem die psychische Stärke seines Helden, der in solchen apokalyptischen Szenarien einen ständigen und erfolgreichen Kampf gegen den Tod führte, hervorheben wollte.

Empfehlungen für die Gestaltung schriftlicher Arbeiten in Studiengängen der Abteilung Information und Kommunikation der Fakultät III der Fachhochschule Hannover

Die für die Abteilung Information und Kommunikation der Fakultät III, Medien, Information und Design – MID (im Folgenden: Abteilung IK) der Fachhochschule Hannover erarbeiteten „Empfehlungen für die Gestaltung schriftlicher Arbeiten“ bieten Anregungen und Erläuterungen zur formalen Gestaltung von schriftlichen Arbeiten, die von den Studierenden im Laufe ihres Studiums an der Abteilung IK als Studien- oder Prüfungsleistungen zu erbringen sind. Sie bringen teilweise ausführliche Beispiele und legen beson-deres Gewicht auf eine Darstellung der Zitiertechnik und der Zitierregeln (auch von Internet-Dokumenten). Weitere Schwerpunkte dieser Empfehlungen sind besondere Richtlinien für die Gestaltung von Diplom- oder Bachelorarbeiten, eine Auflistung der diesen Empfehlungen zugrunde gelegten Literatur und Anhänge (mit Beispielen zur Gestaltung von Titelseiten und Inhaltsverzeichnissen).

Lernende Organisationen - die Nachrichtendienste

Herausgeberwerk (Litzcke & Schuh): 1. Modewellen des Managements 2. Wohin die Reise geht - Folgen des Wertewandels für die Führungskräfteentwicklung 3. Umgang mit Veränderungen - Psychologie für ein erfolgreiches Changemanagement 4. Weiterentwicklung des öffentlichen Dienstes durch Evaluation 5. Qualiätsmanagement im Bundesnachrichtendienst 6. Unternehmen BfV - Realität oder Trugschluss?