In this article the summary of measurement and calculation values of low frequency electric field radiation around the high-voltage transmission lines and impact of the increased voltage values on the AC corona onset voltage gradient are presented. The measurements of the low frequency electric field radiation level were performed under the 400 kV transmission lines of horizontal configuration with standard and compact dimensions. In all cases analyzed in this article, the measurements are performed in the middle of the span, because at this point the conductors are closest to the ground. The analysis in this article has been initiated by the increased voltage values of long duration that have been registered in nodes of the 400 kV network in Bosnia and Herzegovina and the neighbouring countries during the last years. The calculation of the low frequency electric field radiation of the different configuration of the high-voltage transmission lines will be useful for determining the non-ionization radiation exposure levels of the general public in the future as well as to determine their impact on the AC corona onset voltage gradient.

The pa per dis cusses the pos si bil ity of im prov ing the char ac ter of gas surge ar rest ers. Ex am ined were: the mag netic field ef fect, the ef fect of the hol low cath ode, and the ef fect of the al pha ra di a tion source 241Am. Nu mer i cal and real ex per i ments con ducted are pre sented to gether with the o ret i cal in ter pre ta tions of the ob tained re sults. Real ex per i ments were car ried out on a model of a gas surge ar rester spa tially con structed for ex per i ments pre sented in this pa per. The model was de signed in such a way that it was pos si ble to change all the rel e vant pa ram e ters of the gas surge ar rester model. Ex per i ments were con ducted un der well-con trolled lab o ra tory con di tions. The tests were per formed with d. c. and im pulse volt age. The re sults ob tained by ex per i ments were pro cessed by so phis ti cated sta tis ti cal meth ods. The ex pressed mea sure ment un cer tainty of the ex per i men tal pro ce dure showed a high sta tis ti cal re li abil ity of the ob tained re sults. Based on the re sults of the re search, the model of a gas surge ar rester, in which the ef fect of the hol low cath ode and the ra dio ac tive source 241Am were com bined, un am big u ously proved to have the best char ac ter is tics.

Abstract This paper presents a path planning algorithm designed for rigid, free-flying robots. The algorithm is based on recently proposed structure called bur of free C-space. The bur of free C-space was originally developed to improve the exploration of configuration spaces for articulated robots, which further enabled efficient and fast path planning. In this paper, we extend the notion of bur for configuration spaces of rigid body robots that move in 2D/3D spaces, i.e., for Lie groups SE(2) and SE(3). Such defined bur is then used within a suitable RRT-like algorithm. The numerical study shows measurable performance improvements with respect to classical path planning methods.

Semantic fluency (SF) is a suitable indicator of preschool verbal abilities and can be used as a predictor of later school success. This research examined the effects of executive functions (EF) and theory of mind (TOM) on semantic fluency in preschool children. Dimensional Card Sorting test was used as an instrument of executive functions and the Sally-Anne test was used as a measure of theory of mind. The sample for this research comprised 116 preschool children, 60 boys, 56 girls, aged 38-72 months. The results of this research revealed a statistically significant effect of EF on SF (p=.03). The effect of TOM on SF was statistically non-significant, although approaching statistical significance (p=.06). There were no interaction effects of EF and TOM on SF. Findings of this research strongly suggest the need for EF training activities in preschool children. Preschool institutions of 21st century need to have curricula aimed at fostering EF skills.