Lifetime prediction of ABS polymers based on thermoanalytical data

The service life of ABS polymer, stabilized by 2-(3,5-di-tert-butyl-4-hydroxyanilino)-4,6-bis(octylthio)-1,3,5-triazine and containing 50% of a modifying rubber component, was estimated from oxidative induction times measured by DSC in isothermal mode in the temperature interval 140–170°C. The lifetime of ABS powder at the actual temperature of drying was predicted by linear extrapolation according to Arrhenius. However, the extrapolated value was much longer than the real lifetime determined from the long-term oven aging tests at 70 and 90°C, simulating the industrial drying process. The effect of changes in the apparent activation energy of oxidation due to antioxidant consumption during polymer aging is discussed.     

4.50—Polarographic investigation of conformational changes of human serum albumin: Part I. Unfolding of human serum albumin by urea

The mechanism of the unfolding of human serum albumin by urea was studied using d.c. polarography. It was found that this reaction is a complex process which cannot be described in terms of a two-state transition model. As well as the Brdi?ka catalytic current we have also studied the reduction current of disulfide groups in native and denatured human serum albumin. The number of cystine residues accessible for electrode reduction in native and denatured protein was calculated. On the basis of these results a scheme for the unfolding of human serum albumin by urea is proposed.     

Temperature dependence of development of slip bands and of strain hardening in AgCl crystals

The dependence of the flow stress and the slip band density on the plastic strain has been measured at 201 K, 293 K and 363 K. The growth of deformation concentrated in an average slip band has been stated. The types of obstacles acting against the rise and development of a slip band and the temperature dependence of the strain hardening in AgCl crystals are discussed. An equation stating the dependence of the flow stress on the slip band density is presented. The hardening in AgCl crystals is classified as the stage III — hardening.     

160Tb nuclear orientation in yttrium single crystal

First experimental results of¹⁶⁰Tb nuclear orientation in yttrium single crystal matrix are described. The influence of external magnetic field in combination with the crystal field interaction is discussed.     

56,57,60CoFe NMR/ON,hyperfine anomalies and γ-factors of cobalt isotopes

The results of NMR/ON measurements on^56'57'60Co isotopes in iron are presented. To avoid the uncertainties caused by local demagnetizing field inhomogenities the measurements on two cobalt isotopes in one sample have been carried out. The values of nuclear-factor ratios ⁵⁷/ ⁶⁰ = 1.805 (20), ⁶⁰/ ⁵⁶ = 0.761 (20), ⁵⁶/ ⁵⁷ = 0.726 (20) and hyperfine anomalies⁵⁶⁶⁰ = -0.036 (10),^{60 57} = 0.017 (10) and⁵⁷⁵⁶ = 0.018 (10) have been calculated from the experimental results.     

Energy independent number of clusters and multiplicity distribution at Collider and beyond

Multiplicity distributions up to the Collider energies could be described by various two-parameter compounded distributions having in common Poisson distributed number of clusters. Among them the logarithmic distribution for hadronization via decaying clusters leads to energyindependent number of clusters above the ISR energies, replacing the previous KNO-scaling.Dedicated to the 30th anniversary of the Joint Institute for Nuclear Research.     

A comparison of the stochastic theory of the crystal growth and the Stefan problem

The stochastic theory of the crystal growth is compared with the solution of the Stefan problem in the case of Sn solidification. It is shown that the stochastic theory gives the same results as the solution of the Stefan problem if kinetic processes at the solidification front are very rapid.     

Hyperfine anomalies and nuclear γ-factors of56Co,57Co and60Co isotopes studied by NMR/ON

The results of NMR/ON measurements on^56,57,60Co isotopes in iron are presented in the paper. To avoid the uncertainties caused by local demagnetizing field inhomogeneities the measurements on two cobalt isotopes in one sample have been carried out. The values of nuclear-factors ratios ⁵⁷/ ⁶⁰=1·805(20), ⁶⁰/ ⁵⁶ = 0·761(20), ⁵⁶/ ⁵⁷ = 0·726(20) and hyperfme anomalies^{56 60} = –0·036(10),^{60 57} = 0·017(10) and^{57 56} = 0·018(10) have been calculated from the experimental results.Dedicated to the 30th anniversary of the Joint Institute for Nuclear Research.     

On a construction of Thomassen

Using a construction of Thomassen [Discrete Math. 9, 91–96 (1974)] we prove that for infinitely manyn there is a family _n of triangle-free maximally non-hamiltonian graphs of ordern with | _n | exponentially inn. In particular, for everym 48 we construct such a graph; an infinite number of these provide new almost extremal examples in the sense of minimal size.