Bücherschau

Ohne Zusammenfassung VDI     

Dispersion-strengthened copper-based materials formed by high rate magnetron/plasmatron sputtering

A magnetron/plasmatron source was used for sputtering CuTi(0.7 wt.%)Fe(0.9 wt.%) to produce fine-grained (diameter approximately 1 μm) dispersion-strengthened films of thickness 30–100 μm with finely dispersed particles (size less than 25 Å). After sputtering without heat treatment the CuTiFe films showed a large increase in strength (σ_0.2 ≈ 700 MPa; σ_B ≈ 750 MPa; microhardness HV_M ≈ 3000 MPa) and an electrical conductivity of $\text{25–30}\text{m}\text{Ω}{}^{-1}\text{mm}{}^{-2}$, i.e. about half the conductivity of pure copper. The strengthened films remained stable to post-deposition annealing at up to 650 °C.     

Permutational Isomers with Chiral Ligands

Problems in permutational isomerism are discussed in terms of double cosets of permutation groups. A short account of chirality vs. achirality of permutational isomers with pairwise mirror image chiral ligands is presented without mathematical detail.     

Chemical composition of some tissues of the Antarctic fish Notothenia rossii marmorata,fischer 1885

Muscle, liver, stomach, intestinal tract and pyloric caeca of the Antarctic fish Notothenia rossii marmorata, Fischer 1885, were analysed for dry matter, crude protein, carbohydrate, total lipids, ash, chloride, phosphorus and fluoride. It was found that the levels of these classes of substance varied considerably within ten fishes of a pre-spawning community.The highest level of protein was found in the stomach (80·8% mean value on a dry weight basis) and the lowest in the liver (39·6%); for total lipids in the liver and stomach the situation was reversed with the relevant figures being 40·8% and 11·27%, respectively. The pyloric caeca showed a maximum of ash content (6·34%), whilst only 3·92% was found in the liver. The liver was extremely rich in carbohydrates (8·22%) whilst, at 1·64%, the muscle contained least. Although N. rossii marmorata mainly feeds on the fluoride-containing krill (Euphausia superba Dana), the tissues investigated showed only a low level of fluoride (10–40 ppm).     

Verformungsvorgang während der Lüdersbandausbreitung beim Stahl St 42-3

Verformungsverteilung und Verformungsgeschwindigkeit während der Lüdersbandausbreitung an der unteren Streckgrenze. Lüdersfrontgeschwindigkeit als Ortsfunktion. Entstehung von Formabweichungen durch Werkstoffheterogenität.     

Steady-state vibrations of offshore structures

Offshore structures subjected to the action of drifting ice floes may experience several kinds of interactions with the ice feature. This paper addresses the structural response to forces that arise when the ice floe fractures against a vertical structure. Special attention is paid to the steady-state vibrations which may arise at medium ice velocities. The paper describes a straightforward design procedure for the dynamic response of narrow structures. The applicability of simple design concepts is discussed in connection with the design problems of wide offshore structures. Reference is made to recent experimental findings to show that numerical models of dynamic ice-structure interaction provide a promising design tool for both quasi-static and dynamic response of wide offshore structures.Published in Gidrotekhnicheskoe Stroitel'stvo, No. 8, pp. 24–27, August, 1994.     

The measurement of mixing efficiency of continuous mixers

A radiotracer method for testing the mixing characteristics of industrial continuous mixers in actual process conditions is described. The tracer is fed into the input of the mixer at a constant rate and the radiation in the output is measured by two properly collimated radiation detectors. The measurement yields data in the form of two time series which contain information about the radial and axial homogeneity of the tracer in the measuring point. The formulas connecting the information in the measurement data and the axial and radial concentration variation of tracer are derived by the methods of statistical mathematics. The values for experimental parameters are obtained by computer simulation of the radiation measurement geometry.The method was tested by measuring the increase of the homogeneity as a function of mixing distance in a static tube chlorine mixer in a pulp bleaching plant. Also some results obtained on another type of mixers showing the effect of pulp type on mixing are given.