CoGaInS4, eine neue verbindung mit FeGa2S4-struktur

CoGaInS has been prepared by solid state reaction from the binary sulfides at 800°C. It crystallizes trigonally (space group P3m1) with a = 375.9 and c = 1218.4 pm and is isotypic with α-FeGa₂S₄. Co²⁺ and In³⁺ occupy partly octahedral and partly tetrahedral voids. The FIR spectrum of CoGaInS₄ is communicated and discussed in comparison with those of CoGa₂S₄ and CoIn₂S₄.     

MellapakPlus ‐ eine neue Generation strukturierter Packungen

Minor, but decisive changes in the geometry of the successful structured packing Mellapak® have had a marked ef‐fect. In comparison with conventional structured packings, MellapakPlus® increases the capacity in separation columns by some 30 % and reduces the pressure loss appreciably. Behind this success, which can be named a revolution in the field of vacuum distillation, stand a considerable development effort and extensive testing.     

Wirtschaftliche Qualitätskontrolle — eine Übersicht über einige neue Ergebnisse

Zusammenfassung Dieser Artikel gibt eine Übersicht über einige neue Entwicklungen auf dem Gebiet der wirtschaftlichen Qualitätskontrolle. Die Hauptresultate sind ein allgemein anwendbares Konzept zur optimalen Prozeßkontrolle zusammen mit der Herleitung leistungsstarker und zugleich einfacher Methoden zur Bestimmung optimaler Kontrollpläne für eine gegebene Situation und die Entwicklung einer neuen Generation von einfachen Stichprobenplänen für die Produktkontrolle, die die heutige, schärfere Prozeßkontrolle und damit die verbesserte Qualität der angelieferten Warenpartien berücksichtigt.

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Summary This paper gives a review of some new developments in the field of economic quality control achieved since 1980. The main results are a generally applicable approach to optimal control of production processes together with the derivation of powerful and at the same time simple methods to solve the problem of determining the optimal control procedure for a given situation, and the development of a new generation of economic single sampling plans for product control, which take into consideration the nowadays tightened process control and consequently improved quality of incoming lots.

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Arbeit gefördert durch die Deutsche Forschungsgemeinschaft     

Strategische Planung für eine multinationale Unternehmung mit gemischt-ganzzahliger Programmierung

Zusammenfassung Bei der strategischen Planung multinationaler Unternehmungen ist wegen der Komplexität der Problemstellung, der Unsicherheit der Eingabedaten und nicht zuletzt auch wegen der in der Regel wertmäßig beachtlichen Auswirkungen der Strategienwahl mit besonderer Umsicht vorzugehen. Die gemischtganzzahlige Programmierung bietet die Möglichkeit, die wesentlichen, einschlägigen Systemzusammenhänge zu erfassen. In der vorliegenden Arbeit werden dabei die betrieblichen Funktionsbereiche Finanzen, Produktion und Absatz tangiert. Auswertungen des dynamischen Modelles können unter Berücksichtigung einer Risikoanalyse mit verschiedenen Varianten von Eingabedaten durchgeführt werden. Ferner können Interdependenzen von Modellvariablen aufgezeigt werden, wie z. B. die Abhängigkeit des Konzernkapitalwertes von verschiedenen Gewinnbildungs- und Ausschüttungsstrategien.

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Summary Strategic planning in companies with activities in different countries requires some care out of different reasons, e.g. the complexity of the problem, the uncertainty of input data and last not least the considerable consequences of the selection of strategies. The essential interdependences of the problem above can be formulated as a mixed integer program. In this paper especially finance, production and sales of the company are considered. Calculations can be done with the model under the aspect of risk analysis with different sets of input data. Further interdependences of variables of the model can be shown, i.e. the development of the corporatecapital-value as a function of different strategies for profits and dividends.

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Erweiterte Fassung eines Vertrags auf der Jahrestagung der DGOR am 2. 10. 1981 in Göttingen     

Vorstoff-Optimierung für eine Bleihütte mit Hilfe eines LP-Modells

Zusammenfassung Eine Bleihütte wird vorwiegend mit gekauften Vorstoffen versorgt, die sich erheblich nach Art und Zusammensetzung unterscheiden und in verschiedenen Produktionsstufen eingesetzt werden. Die Vorstoffbewertung mit dem Ziel eines optimalen Betriebsergebnisses ist wegen der umfangreichen Materialkreisläufe nur durch Anwendung von OR-Verfahren möglich. Es wurde ein Linear-Programming-Modell entwickelt, das die Bedingungen zur Ermittlung von Kosten und Erlösen sowie alle technischen Zusammenhänge umfaßt. Das Modell ermöglicht neben der Berechnung optimaler Beschaffungs- und Mischungspläne auch Entscheidungen über Verbesserungen der Verfahrenstechnik.

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Summary Most of the raw material feed for a lead smelter is purchased from outside. These raw materials have a wide bracket of both kind and composition and are used in the various stages of the production process. Owing to the many material circuits, raw material evaluation, aiming at an optimized operating result, is only possible by means of operations research methods. A linear programming model has been developed, comprising both the conditions for costs and proceeds and all technical relations. Besides the calculation of optimum supply and mixing schedules, the model also permits to take decisions regarding any improvements of process engineering.

     

Sekundärströmung in Schaufel(ring)gittern mit Pfeilung und V-Stellung – eine Literaturstudie

One goal in designing fluid machinery is to maximise the efficiency. The rotor and the stator of such machines are comprised of rotating and stationary cascades. In addition to the main flow a secondary flow develops which depends on the operation point. The efficiency of the cascade is affected by this flow. The secondary flow, including the gap flow, can reach up to 20–40% of the total hyraulic losses in modern axial flow turbines. A reduction of these losses can remarkably affect the efficiency. In order to achieve this an exact understanding of the formation and the development of the secondary flow is required. If the designer properly understands the secondary flows, the interaction between them and the parameters which influence the secondary flows, it is possible to design cascades with reduced secondary losses by using proper design criteria. Shape and extend of the secondary flow mainly depend on flow parameters and geometric parameters. Flow parameters are, for example, the incidence angle, the boundary layer thickness and the turbulence. Geometric parameters are for example the distribution of the blade load, shape and radius of the leading edge, the aspect ratio, boundary layer fences, dihedral and sweep of the blade. The latter two geometric criteria can be regarded efficient means to model the pressure on the endwalls and, therefore, the development of the secondary flow.     

The control system of the polarized internal target of ANKE at COSY

The polarized internal target for the ANKE experiment at the Cooler Synchrotron COSY of the Forschungszentrum Jülich utilizes a polarized atomic beam source to feed a storage cell with polarized hydrogen or deuterium atoms. The nuclear polarization is measured with a Lamb-shift polarimeter. For common control of the two systems, industrial equipment was selected providing reliable, long-term support and remote control of the target as well as measurement and optimization of its operating parameters. The interlock system has been implemented on the basis of SIEMENS SIMATIC S7-300 family of programmable logic controllers. In order to unify the interfacing to the control computer, all front-end equipment is connected via the PROFIBUS DP fieldbus. The process control software was implemented using the Windows-based WinCC toolkit from SIEMENS. The variety of components, to be controlled, and the logical structure of the control and interlock system are described. Finally, a number of applications derived from the present development to other, new installations are briefly mentioned.     

Sekundärströmung in Schaufel(ring)gittern mit Pfeilung und V-Stellung — eine Literaturstudie

One goal in designing fluid machinery is to maximise the efficiency. The rotor and the stator of such machines are comprised of rotating and stationary cascades. In addition to the main flow a secondary flow develops which depends on the operation point. The efficiency of the cascade is affected by this flow. The secondary flow, including the gap flow, can reach up to 20–40% of the total hyraulic losses in modern axial flow turbines. A reduction of these losses can remarkably affect the efficiency. In order to achieve this an exact understanding of the formation and the development of the secondary flow is required. If the designer properly understands the secondary flows, the interaction between them and the parameters which influence the secondary flows, it is possible to design cascades with reduced secondary losses by using proper design criteria. Shape and extend of the secondary flow mainly depend on flow parameters and geometric parameters. Flow parameters are, for example, the incidence angle, the boundary layer thickness and the turbulence. Geometric parameters are for example the distribution of the blade load, shape and radius of the leading edge, the aspect ratio, boundary layer fences, dihedral and sweep of the blade. The latter two geometric criteria can be regarded efficient means to model the pressure on the endwalls and, therefore, the development of the secondary flow.     

Beschichtung von Implantaten mit Hydroxylapatit: Die Option auf eine stoffschlüssige Verbindung zwischen Knochen und Metall

Implants Coated with Hydroxyaptit: The Option for Joining Metal to Hard Tissue Load bearing components for artificial joints are made of bioinert alloys. These implants can only be joint to bone by form closure or frictional connection. Coating bioinert implants with bioactive hydroxyaptite ceramics (HA) offers the option to have a biological interaction between the bone and the coated implant. This way tensile forces can be transfered to the implant. This papers reviews material properties and recommendations how to design plasma sprayed HA-coatings for total hip replacement. There is clinical proof that due to the enhanced interaction between the HA-coating and the implants an excellent bonding can be achieved, i. e. long-term osseointegration or biological/chemical interaction between inert anorganic materials and vital tissue. There are no technical problems coating implants with HA. Clinical results based on more than 10 years are available.     

Eine neue Zustandsgleichung des Wasserdampfes

Ohne Zusammenfassung Ein Erratum zu diesem Beitrag ist unter zu finden.     

Wissenschaft und Legende: eine Nachbetrachtung zu “Lise Meitner, Otto Hahn und die Kernspaltung: eine Legende aus unseren Tagen”

It is shown in more detail how the well-documented history of nuclear fission in 1938/9 has been distorted by a legend.      

New Turbomolecular Pump with Central Opening for Free Axial Access. Eine neue Turbomolekularpumpe mit zentraler Öffnung für freien axialen Zugang

Standard turbomolecular pumps show typically one annular active intake area on the high vacuum flange side (single‐flow pumps). The central circular part of the inlet of the compressor turbine is blind for pumping. The new design proposes a central opening of a turbomolecular pump all along the axis. This central bore can be used e.g. for mounting of feed throughs, manipulators, windows or for coupling to further vacuum devices, in particular also for enclosing tube‐like vacuum systems. This design allows a multi‐use of a pumping port at a vacuum vessel without reducing there the pumping speed. Moreover, the new design is ideal for axial or radial differential pumping arrangements as e.g. needed for all gas jet like set‐ups or other pressure reduction stages.