Dynamic tear tests of carbon weldable steels

For determining the crack arrest temperature of structural weldable steels of mass production, it is convenient to use the dynamic tear test because of its simple and low cost application using drop weight testers or pendulum testing machines. The dependence of the dynamic tear energy on temperature can in fact represent the curve of the crack arrest temperatures. The energy/temperature results have to be transformed into the nominal stress vs. temperature coordinates to permit a better review and simpler application. This work describes two methods of making such transformations and shows some results acquired with carbon weldable structural steels.     

High conversion polymerization of α-methylstyrene with maleimide at different monomer-to-monomer ratios in the feed

Summary High conversion polymerization of -methylstyrene (-MeSt) with maleimide (Ml) was performed in Calvet differential microcalorimeter under different monomer-to-monomer ratios in the feed using AIBN as initiator. From the calorimetric curve it was observed that in the presence of an excess of Ml, alternating copolymer is quantitatively formed prior to the formation of poly (Ml).     

New control concept of anthropomorphic manipulators

In this paper is presented a new control concept of anthropomorphic manipulators for industrial application. A new algorithm is given for finding the dynamic equations of open kinematic chains using a digital computer. The synthesis of the programmed dynamics has been performed via prescribed motion kinematics. The synthesis of the compensating movement level was proposed too, by measuring contact forces between the object and the terminal device. The presented example of a 6 degrees-of-freedom anthropomorphic manipulator illustrates the proposed approach to manipulator control.     

Residual shear strength of soils

Conclusion The relations between the residual shear strength of soils and their index properties have been proved. Best correlation appeared to be between the residual shear strength and the index of plasticity. However, the correlation is not enough to enable the simple index tests to be substituted for the complex residual shear tests.     

An indirect method for the detection of changes in power network configuration

This paper presents an indirect procedure for determination of power network topology. The procedure applies the methods of state and parameter estimation, using redundant and noisy measurements, and a power system model in the steady state for some known basic network topology. Detection of changes in a network topology related to a basic topology is done by monitoring a suitably selected performance index during the process of static state estimation, while the location of changes requires additional criteria. The paper describes the development of a mathematical algorithm and gives some simulation results obtained on a real power network.     

Statistical study of tram driver accidents

This statistical study considers two basic hypotheses on industrial and traffic accidents the accident proneness theory and the spell theory. The two hypotheses were tested on the basis of a correlation analysis of accident distribution in a group of tram drivers over a five year observation period. Using the chi-square goodness of the test. the analysis showed the negative binomial distribution and the “short” distribution were successfully fitted,while the Poisson distribution significantly differed from the observations. Correlation analysis showed a significant correlation between the number of tram driver accidents over different periods, and that this correlation. although decreasing with an increase of the interval between observation periods, remained significant. The conclusion is that the proneness hypothesis explains more satisfactorily than the spell hypothesis the occurrence of accidents in tram drivers during tlie observation period.     

Formation of an intermediate C-S-H phase during the hydrothermal synthesis of gyrolite

An intermediate C-S-H phase, similar to the Assarsson's “Phase Z”, with basal spacing of 16Å formed when β-C₂S or γ-C₂S reacted with silicon dioxide (molar ratio CaO/SiO₂ = 0.5–0.28) for 8 hours at 190°C under hydrothermal conditions. This intermediate C-S-H phase transformed to gyrolite upon prolonged hydrothermal treatment.     

Formation of Pb during epitaxial growth of PbS on KCl in a vitreous silica hot wall system

Thin monocrystalline films of PbS grown epitaxially from the vapour on KCl in a vitreous silica hot wall system, present lower specular reflectivity than expected. Electron micrography shows that the surfaces of the films are studded with a multitude of small blobs. They scatter partially the incident light. By electron probe microanalysis and Bragg diffractometry it was found that the blobs are made up of elemental Pb and PbS. As basic lead sulphates were also found on the films the presence of elemental Pb is attributed to the roast reduction reaction. We believe that the silica of the apparatus provides the major part of the oxygen involved in this reaction.     

Non-equilibrium phases in Al-rich Al-Pt alloys

The solid solubility of Pt in Al was extended from 0 to 2 at. % by “two-piston” quenching technique. The stability of the Al-Pt solid solution during annealing is discussed. During the decomposition an intermediate metastable phase was detected, the unit cell constants of which were determined.