Preparation of an ultra-oriented polyethylene morphology

A technique for producing an ultra-drawn morphology for high-density polyethylene has been described previously. This technique has subsequently been extensively modified to produce the ultra-drawn morphologies under continuous and more versatile conditions. These changes involve using the reservoir of an lnstron rheometer to prepare a crystal morphology prior to proceeding with a solid state (crystal-crystal transformation) extrusion process in the same instrument. The new preparation conditions are described to up-date the prior procedure and to document this new method which is now being employed in several laboratories to produce transparent polyethylene morphologies of extreme orientation and chain extension which results in filaments and films of extreme tensile moduli.     

On the optimum ratio of distance between wires to conductor radius of symmetrical star quad cable for digital signal transmission

Existence of an optimum ratio of distance-between-wires/conductor-radius for minimisation of symmetrical star quad cable loss, when the distance between wires is constant, is confirmed by calculated and measured results using symmetrical star quad cable in the high frequency domain, such as digital signal transmission.     

The effects of a moving anisotropic grounded layer on radiation from a line source

The radiation from a magnetic or an electric current line source embedded in an uniaxially anisotropic grounded dielectric or plasma layer moving perpendicular to the line source is described. The radiation pattern is obtained, and the effects of the motion of the layer on the radiated power distribution are examined with several numerical examples.     

Influence of doping on the electronic structure of (La, Sr)2CuO4

High-statistics (>4 × 10⁸ counts), room-temperature measurements of the electron-positron momentum density of La_2–x Sr _x CuO₄ have been performed for samples with Sr concentrations of x=0.0, 0.1, 0.13, and 0.2. These spectra have been analyzed in conjunction with theoretical calculations of the electron-positron momentum density. The metallic samples show features consistent with the presence of a Fermi surface, but its evolution with increasing Sr concentration does not follow the predictions of band theory. These results may indicate the effects of electron-electron correlation on the electron momentum distribution in the Cu-O plane.     

Schwingungsverschleißfestigkeit von plasmanitriertem, 34 CrAlMo 5

Fretting Fatigue Strength of Plasmanitrided 34 CrAlMo 5 Fretting fatigue load here means oscillating sliding movements of very small amplitude (1–3 μm) and synchronous fatigue load. Characteristic of this is the appearance of frettings. These surface damages lead to the formation of microcracks, which spread and finally lead to the premature fatigue failure of the component. To simulate such processes of damage, which are known of the bearing surfaces of roller bearing races, of turbine blades and of shaft-hub-combinations, a fretting bridge apparatus is used. The plasmanitriding and plasmanitrocarburizing of metals are thermochemical heat treatments, which change the microstructure of near to surface areas. By means of this the mechanical and technological properties of components, e.g. wear and corrosive resistance as well as fatigue strength, are improved. Dur to the advantage sof the process, plasmanitriding is already used in many regions of production. Investigating the fretting fatigue strength of plasmanitrided respectively plasmanitrocarburized 34 CrAlMo 5 shows, that these treatments improve the fatigue strength values to a level 14% higher, the fretting fatigue strength increases about 50%.