Results obtained by studying the possibility of replacing cement in mortars with local industrial by-products, i.e. with silica fume and red mud, are provided in the paper. The results of fresh and hardened mortar properties tests conducted on five mixtures in two series are presented. 10% of cement was replaced with silica fume, and 0%, 5%, 10%, 15% and 20% of cement weight was replaced with red mud. The first series was tested after 28 days of curing, and the second series was subjected to freezing and thawing cycles after proper curing, and then submitted to testing. The results point to satisfactory behaviour of mixtures with a low red mud content.

We consider sequential packings of families of circles in the plane whose curvatures are given as members of a sequence of non-negative real numbers. Each such packing gives rise to a sequence of circle centers that might diverge to infinity or remain bounded. We examine the behavior of the sequence of circle centers as a function of the growth rate of the sequence of curvatures. In several special cases we obtain explicit formulas for the coordinates of the limit, while in other cases we obtain accurate estimates.

Previous research highlighted undoubtedly positive impact of transformational leadership on a wide range of performance, including its follower, individual and organizational levels. However, the focus to date has mainly been on the concept’s empirical underpinnings and, hence, the purpose of this study is to present and clarify the intellectual structure of transformational leadership – performance relationship studies. Building on the bibliometric analysis, we have provided the information on publishing trends, the most prolific countries and authors that shape this relationship, whereas term analysis provides a taxonomy for ongoing and recommended upcoming research in the field. The results showed a) the field is under a surprisingly strong influence of a diversified research context along with the focus on the well-recognized and expected Anglo-American region; b) there are five clusters which have been recognized as representatives of the field; c) scarcity of research into sales and managerial performance has been identified which indicates that there is a considerable potential for wide-ranging research in fields of marketing and management in general. In the context of contribution, this study provides a reference to researchers entering this field, as well as guidance for future research.