A retarding structure that allows the effective admittance of a tube wall to increase smoothly along the tube axis is considered. The sound velocity gradually decreases along a finite segment of the t

The world’s largest community of scientists disintegrated following the dissolution of the Soviet Union. With extremely scarce resources and limited academic freedom as starting points, researchers in this region have been creating new knowledge; they have been building on rich scientific traditions in selected disciplines and, at times, paving new paths in non-traditional disciplines. At present, the cumulative contribution of post-Soviet countries to global research output is only three percent, indicating that these countries are not key players on the global research scene. This study uses bibliometric methods to offer novel empirical insight into the quantity and impact of academic publications; it also looks at the quality of journals in which the output is published. The findings reveal that fifteen post-Soviet countries differ considerably in terms of how much they have prioritised research, as well as the quantity, quality, and impact of their publications. The research productivity across the region has not been high and, taken together, these countries have produced publications of considerably lower quality and lower impact when viewed in the context of global research output. At the same time, researchers from post-Soviet countries tap into international collaborative networks actively, resulting in an exceptionally large proportion of publications from this region being internationally co-authored. In the historical context of Soviet research being known as one of the least collaborative globally, this finding indicates that researchers in the region are attractive to international collaborators and may be seeking such partnerships due to relatively modest research capacity at home.