Untersuchungen an bewitterten Holzoberflächen—4. Mitteilung: Versuche mit einem Imprägnieranstrich auf Basis der Madison-Formula

Zusammenfassung Auf der Grundlage der vorangegangenen Untersuchungen wurde der ziemlich wetterbest?ndige, feuchtigkeitsschützende Impr?gnieranstrich “Madison-Formula” des Forest Products Laboratory/Madison, USA, unterschiedlich pigmentiert und, anstelle von Pentachlorphenol der Originalrezeptur, mit verschiedenen Fungiziden gegen dunkelf?rbende Schimmelpilze versehen. Die unpigmentierte Anstrichvariante erwies sich als zu wenig halthar, die wei? und die umbra pigmentierte dagegen als recht dauerhaft. 4 organische Metallsalzverbindungen, die im Laborversuch als die wirksamsten Fungizide ermittelt worden waren, konnten aufgrund der Ergebnisse der Freiland-Bewitterungsversuche nur teilweise befriedigen. Die beste Wirksamkeit zeigte eine Cu-Verbindung, die allerdings eine ausgepr?gte Eigenf?rbung besitzt. Einige Schutzmittel beeintr?chtigten die Anstrichhaltbarkeit. Pigmentierung und Fungizide hatten teilweise einen starken Einflu? auf die Holzfeuchte der Probebretter und auf die Holzfeuchteschwankungen.

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Investigations on weathered wood Surfaces—Part IV: Tests with an impregnating paint on “Madison Formula” basis

Summary On the basis of the previous investigations the rather weather and moistureproof impregnating paint “Madison-Formula” of the Forest Products Laboratory, Madison, USA, was pigmented to different degrees and provided with various fungicides against dark-staining mould fungi, instead of pentachlorphenol of the original formula. The non-pigmented paint was found to be less permanent, the white and umbra pigmented paint, however, proved quite resistant. Four organic metal salt composites, found to be the most efficient fungicides in laboratory experiments, were satisfactory only to some extent, as the results of field weathering revealed. A copper compound proved most efficient, which possesses, however, a pronounced natural colour. Some preservatives affect the durability of the paint. Pigmentation and fungicides partly had a strong effect on the wood moisture of the board specimens and on wood moisture variations.

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1. Mitteilung: Kühne, H., Leukens, U., Sell, J., W?lchli, O. [1970]; 2. Mitteilung: Sell, J., Leukens, U. [1971]; 3. Mitteilung: Sell, J. Leukens, U. [1971].     

Effect of deformation conditions on the transformation of micro-alloyed medium-carbon forging steels

The CCT diagrams of three medium-carbon steels without and with microalloying by vanadium and titanium were constructed by applying direct cooling of as-deformed austenite. Deformation parameters corresponding to those of industrial forging were varied with a laboratory simulation technique by using the plane strain hot compression test. The effect of microalloying, deformation, and deformation temperature on the amount of structural substituents was quantified. For practical application of the study the as-forged controlled cooling conditions were determined to achieve the desired bainite-free ferritic-pearlitic microstructure with beneficial mechanical properties.     

Parameterized High Throughput Function Evaluation for FPGAs

This paper presents parameterized module-generators for pipelined function evaluation using lookup tables, adders, shifters, multipliers, and dividers. We discuss trade-offs involved between (1) full-lookup tables, (2) bipartite (lookup-add) units, (3) lookup-multiply units, (4) shift-and-add based CORDIC units, and (5) rational approximation. Our treatment mainly focuses on explaining method (3), and briefly covers the background of the other methods. For lookup-multiply units, we provide equations for estimating approximation errors and rounding errors which are used to parameterize the hardware units. The resources and performance of the resulting design can be estimated given the input parameters. A selection of the compared methods are implemented as part of the current PAM-Blox module generation environment. An example shows that the lookup-multiply unit produces competitive designs with data widths up to 20 bits when compared with shift-and-add based CORDIC units. Additionally, the lookup-multiply method or rational approximation can produce efficient designs for larger data widths when evaluating functions not supported by CORDIC.     

Analytical and experimental investigations of the vibrations of a hollow blade model of turbines

The practice of using air-cooled blades for the increased efficiency of turbine stage is a recent feature with advanced aero-engines. The objective of the present paper is to describe the results of numerical and experimental investigation of the dynamical behaviour of hollow cross-sectioned blades. The analytical method consists in modelling the blades by means of a finite-element method to determine the natural frequencies and normal modes of a hollow cross-sectioned blade model. Numerical results are compared with experimental values obtained from holographic tests.     

Investigation of direct cooling in drawing steel wire

Experimental set-up of direct cooling in drawing steel wire. Calculation of the obtainable temperature drop in cooling tubes. Cooling rates measured at different operation parameters. Evaluation of friction coefficient. Thickness measurement of lubricant layers. Examination of mechanical properties of drawn wire.     

The ring compression test as simulation test for the investigation of friction in hot metal forming

Forces and flow of material in metal working decisively depend on friction between workpiece and tool, which can be described by the friction factor m. For investigation of the influence of friction in hot forming of steel and for measurement of the friction factor, the ring compression test is used as simulation test. The influences of material, reduction, strain rate, temperature, and lubricant are discussed.     

Richtspaltform und Bewegungsverhältnisse beim Richten von Rundstäben in Zwei-Walzen-Richtmaschinen

Besonderheiten des Zwei-Walzen-Richtens. Geometrie des Richtspalts: Schnitt der Biegeebene der Stabachse mit der hyperbolischen und der zylindrischen Walze, Berührungslinien zwischen Stab und Walzen, Biegelinie der Stabachse und größtmögliche Stabdurchbiegung. Kinematik des Richtvorgangs: Umfangsgeschwindigkeiten der hyperbolischen und der zylindrischen Walze, Vorschub- und Umfangsgeschwindigkeit des Stabes bei freier Biegung des Stabes und bei Biegung mit Querprägen, Schlupf. Anzahl der Biegungen eines Stabelementes und der Überrollungen eines Oberflächenelementes beim Durchlaufen der Maschine.     

The use of bismuth-backings for in-beam gamma spectroscopy

A method to prepare rolled bismuth foils is described and their advantages as target backings for in-beam γ-ray spectroscopy at beam energies below the Coulomb threshold of bismuth are discussed.