Examination of Low-Cyclic Fatigue Tests and Poisson's Ratio Depending on the Different Infill Density of Polylactide (PLA) Produced by the Fused Deposition Modeling Method.

This article examines the impact of fatigue cycles on polylactide samples produced by 3D printing using the FDM method. Samples were printed in three infill degree variants: 50%, 75% and 100%. To compere the influence of infill degree on PLA properties, several tests, including the uniaxial tensile test, the low-cycle fatigue test, differential scanning calorimetry (DSC) and scanning electron microscopy (SEM), were conducted.

The Inclusion of Other-Sex Peers in Peer Networks and Sense of Peer Integration in Early Adolescence: A Two-Wave Longitudinal Study.

The main goal of the analysis presented in this paper is to examine the dynamics of including other-sex peers in the peer networks of early adolescents, aged 11 (at T1) and 13 (at T2), and the relationship between sex heterophily and changes in the sense of peer integration. The analysis was conducted using the Latent Difference Score (LDS) model with data from a representative nationwide longitudinal study in Poland (n = 5748). With reference to the dynamics related to the heterophilic process, the research confirmed that at the beginning of grade 5 of primary school, heterophily is still relatively rare, yet towards the end of early adolescence, there is a gradual shift, more strongly in girls, towards breaking through the strictly same-sex segregation and embarking on heterophilic relationships.

The Study of Physico-Mechanical Properties of Polylactide Composites with Different Level of Infill Produced by the FDM Method.

The aim of this study was to evaluate the changes in physical-mechanical properties of the samples manufactured by 3D printing technology with the addition of varying degrees of polylactide (PLA) infill (50, 70, 85 and 100%). Half of the samples were soaked in physiological saline. The material used for the study was neat PLA, which was examined in terms of hydrolytic degradation, crystallization, mechanical strength, variability of properties at elevated temperatures, and dissipation of mechanical energy depending on the performed treatment.

Stereoselection at the steady state in radical cyclizations of acyclic systems containing one radical acceptor and two precursors in a 1,5-relationship under pseudo-first-order conditions.

The first example of a successive kinetic resolution of acyclic diastereomeric radical intermediates in a 1,5-relationship under pseudo-first-order conditions is reported. A mechanistic model involves nonselective generation of the radical intermediates followed by different partitioning of these between two different chemical pathways. The "2,5-cis" selectivity in the radical cyclization step arises from transition geometries with the substituents aligned in pseudoequatorial positions.