Repetition bend properties of Cu-Cr and Cu-Cr-Sn alloys

Repetition numbers of bending of Cu-0.81 wt% Cr, Cu-0.81 wt% Cr-0.14 wt% Sn and Cu-0.26 wt% Cr-0.10 wt% Sn alloys were investigated. After solution treatment, the first two types of copper alloys have a primary chromium phase; this is not so in the last alloy. The primary chromium phase does not influence the repetition numbers of bending of cold-rolled specimens; the repetition numbers of bending of specimens aged at 723 K for 1.8 × 10³ sec after cold rolling are higher than those of cold-rolled specimens. The cause of this is considered to be a recovery of work-hardening during ageing.     

Vinyl polymerization, 399. Polymerization of methyl methacrylate with sodium polystyrenesulfonate in presence of polyethyleneglycol

The effect of polyethyleneglycol on the radical polymerization of methyl methacrylate initiated with an aqueous solution of sodium polystyrenesulfonate was studied. Under the definite condition, the conversion of methyl methacrylate raised from 6.6 to 100% by the addition of polyethyleneglycol. It was concluded that polyethyleneglycol acted only as a host of Na⁺, but not as a phase transfer catalyst.     

Rate of change of oxygen chemical potential in liquid PbO−SiO2 binary solution

The rate of the chemical potential change of oxygen in a liquid PbO?SiO₂ binary solution, with SiO₂ contents of 10, 20, and 30 mol pct, and in pure PbO, has been measured at temperatures of 900°, 950°, 1000°, 1050°, and 1100°C. The rate increased with temperature according to the Arrhenius type relation and decreased with the increase of the silica content. It is suggested that the rate-controlling step is the counter diffusion rate of Pb²⁺ and Pb⁴⁺ ions, which are considered to be the most easily movable ions in the PbO?SiO₂ solution. The relation between the rate of oxygen chemical potential change and the electrical conductivity is also discussed for the liquid PbO?SiO₂ system.     

Studies on absorbed water in cellulose by broad-line NMR

Nuclear magnetic resonance absorption spectra of linter cellulose containing various amounts of water were studied to clarify the relation between the amount of absorbed water in cellulose fiber and the molecular motion in such a cellulose–water system. An amorphous cellulose sample was used for the sake of comparison. The changes in line width and second moment of the spectra were measured at various temperatures. From the variation with temperature of the first-derivative curves and the second moments, it has been inferred that the proton movement of absorbed water changes markedly over the approximate range 180°–200°K and that the absorbed water lowers the glass transition temperature of cellulose to room temperature.     

Processing by equal-channel angular pressing: Applications to grain boundary engineering

Equal-channel angular pressing (ECAP) is a processing technique in which a sample is pressed through a die constrained within a channel so that an intense strain is imposed without incurring any change in the cross-sectional dimensions of the sample. This procedure may be used to achieve considerable grain refinement in pure metals and metallic alloys with as-pressed grain sizes lying typically within the submicrometer range. Careful experiments reveal only a minor change in the grain size with increasing numbers of passes through an ECAP die but there is a significant change in the distribution of grain boundary misorientations as a function of the total imposed strain. In practice, the microstructure evolves with increasing strain from an array of grains where the boundaries are predominantly in low-angle misorientations to an array of grains where a high fraction (typically ≥60%) is in high-angle misorientations. This evolution has a significant effect on the characteristics of the as-pressed materials including the high temperature mechanical properties and the measured rates of diffusion. In addition, the evolution provides an opportunity to use Grain Boundary Engineering in order to optimize the behavior of the material.     

In vivo scattering measurement of biological tissue by the use of a pyroelectric polymer transducer

We propose a new method, to our knowledge, for noninvasive scattering measurements of tissues by the use of a pyroelectric polymer transducer, poly(vinylidene fluoride trifluoroethylene) film. In this method, samples are irradiated with nanosecond, low-energy light pulses delivered from an optical fiber, and the pyroelectric signal induced by the diffuse reflectance is measured with a transducer. The signal is then converted into diffuse reflectance by use of a calibration factor. The validity of this method was confirmed by our measuring the scattering coefficient of a white acrylic resin within an accuracy of +/- 15%. We attempted to apply this method to the estimation of scattering coefficients of normal and burned skins in rats in vivo.     

Effects of manufacturing conditions on the properties of coal-derived caking additives

Manufacturing conditions of coal-derived caking substances (SRC) were investigated to determine the effects of these conditions on the chemical and caking properties of the additives. The solvent-refined coal (SRC) produced in the early stage of digestion at the lower temperature, of which β- and γ-fractions were 55 and 35 wt %, respectively, consisted of a heterogeneous mixture characterized by a low aromaticity, long side-chains, and a large, average molecular weight. The Roga index of the SRC was large but its total dilatation was small. As the digestion proceeded, the condensation and the cycloaromatization reactions improved the homogeneous nature and decreased the molecular weight by the breakage of side-chains, dealkylation, and deoxidation, leading to increases in the γ-fraction and total dilation by decreases in the β-fraction and Roga index. Such trends were more marked when the conversion exceeded 90 wt %. The relation between structure and the caking properties of the SRC are discussed.     

Influence of shearing history on the rheological properties and processability of branched polymers. III. An amorphous long-chain branched polymer

Viscoelastic properties of branched polymers vary with their shearing history; notwithstanding, their primary molecular parameters do not change. According to a recent study, such viscoelastic variation was believed to be observed only with crystalline long-chain branched polymers such as low-density polyethylene or polyacetal. That is, the origin of the viscoelastic variation was attributed to the presence of specific entanglements at the branching points, which was formed during the crystallization process. However, the viscoelastic variation of the long-chain branched polymers is the phenomenon at temperatures well above their melting points, namely, it is considered that whether the long-chain branched polymers are crystalline or not is not essential for the occurrence of the viscoelastic variation. Thus, the influence of the shearing history on the rheological properties of an amorphous long-chain branched polymer was investigated in this paper, and it was found that, irrespective of their crystallinity, the viscoelastic properties of long-chain branched polymers vary according to their shearing history.