Lurie, S. A.; Volkov-Bogorodskiy, D. B.; Knyzeva, A. G.; Panin, S. V.; Kornienko, L. A.
Friction properties being influenced by scale effects are simulated in the paper by the example of polymer composite material made from Ultra High-Molecular Weight Polyethylenes (UHMWPE) filled by calcium stearate (C36H70CaO4). Of interest are the composites whose mechanical properties and tribotechnical characteristics do not depend monotonically on filler (inclusions) weight fraction. In order to describe the influence of scale effects onto frictional properties the model based on Reiss averaging (model of "weak phase") is employed. It is also suggested that when gradient elasticity theory is applicable the formal analogy between effective friction coefficient for surface heterogeneous structures and effective mechanical properties (compliances) for heterogeneous material can take place. Theoretical dependence to describe nonmonotonic change of effective friction coefficient versus filler concentration was obtained for the polymer composites under study. The suggested expressions might be useful for the sake of properties prognosis of antifriction polymeric materilas.
Creel, Sarah C.; Aslin, Richard N.; Tanenhaus, Michael K.
The role of segment similarity (C1-C2-or -V1-V2) in a word learning task was assessed using an artificial lexicon in a referential context. Learning consisted of 480 trials in which S's heard one of 40 CVCV nonsense strings, accompanied by an unfamiliar picture. In testing, participants heard the direction ``Click on the [nonsense word],'' and chose one of four pictures that matched the test item. On some trials, target lexical items (pibo) appeared with foils that contained matched consonants (pabu) or matched vowels (diko). There were higher rates of confusion errors to the matched-consonant items than to non-matched items, but no significant elevation in errors to matched-vowel items. A second experiment examined the role of differences in informativeness between C's and V's by inverting the numbers of C and V types (first experiment: 10 C, 5 V; second experiment: 5 C, 10 V). This made the consonants less predictive of word identity (more words contained the same consonants), and made the vowels more predictive of word identity. The matched-consonant effect remained undiminished while no corresponding matched-vowel effect emerged, ruling out a segment-informativeness explanation. Other accounts based on the syllable positions and confusability patterns of consonants are being explored.