Investigation of the influence of melt-impregnation parameters on the morphology of thermoplastic UD-tapes and a method for quantifying the same

During the production of unidirectional fibre-reinforced thermoplastic semi-finished products (UD-tapes) in melt-impregnation processes, parameters such as melt viscosity, production speed and impregnation die setup have a significant influence on the quality of the produced UD-tapes. These influences are investigated in this article by producing UD-tapes in an extrusion-based melt-impregnation process with varying impregnation parameters. To quantify the homogeneity of the fibre distribution, a method is presented and applied, in which microscopic cross-sectional images of the UD-tapes are analysed and a homogeneity coefficient is calculated. The porosity is also determined by analysing microscopic cross-sectional images of the UD-tapes. The results show that a decreased melt viscosity and a high number of redirection elements in the die have a positive influence on the homogeneity of the fibre distribution. Furthermore, a significant influence of the melt viscosity, the production speed and the die setup on the porosity was proved.

Express Method to Estimate Structural Imperfection and Bone Tissue Status

A new method for evaluating the bone status using the scattering parameter of hardness indexes (Weibull homogeneity coefficient m) is proposed. A comparative analysis of the condition of the bone tissue of birds, depending on age, breed and calcium content, is conducted. It is established that the scattering degree of mechanical properties, in particular, hardness, is a very structure-sensitive parameter.

Unidimensionality and Cumulativeness of the Loneliness Scale Using Mokken Scale Analysis for Polychotomous Items

The unidimensionality and cumulativeness of the Loneliness Scale of De Jong-Gierveld was investigated using the Mokken Scale Analysis for polychotomous items. 10 of the 11 items of the original Loneliness Scale constituted a unidimensional, cumulative scale, with a homogeneity coefficient H of 0.37 and a reliability coefficient rho of 0.88.

Homogeneity Reliability of the it Scale for Children

Although the It Scale for Children (IT scale) is probably the most commonly used measure of sex-role preference in children, its test homogeneity has not been previously reported. The IT scale was administered individually to 38 boys and 40 girls in grades N through 2 of a university school by either a male or a female experimenter. The homogeneity coefficient for girls was larger than that for boys ( p < .01). Neither the Sex of E nor the interaction, Sex of S × Sex of E, was significant. Although the coefficients for girls and boys were large enough for basic research, only the coefficient for girls was large enough for diagnostic work with present sample sizes. Further investigation of the test homogeneity of the IT scale was suggested.