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.

Trivalent chromium is an essential trace element for humans and animals and it is the final product of hexavalent chromium reduction in the cell. It is an integral part of the glucose-tolerance factor, which increases the systemic impact of insulin. The aim of this study was to analyse the effect of trivalent and hexavalent chromium on selected biochemical parameters in Japanese quails. Birds were divided into three groups: group I (control group, n=12), group II (treated with trivalent chromium, n=12) and group III (treated with hexavalent chromium, n=12). During 20 days of follow-up, control and experimental groups of quails had identical diet; chromium was added daily into the food (5 mg/kg) and water (5 mg/L) of the experimental groups. Glucose concentrations were the highest in Group III, while lowest glucose concentrations were obtained in Group I. There were higher differencies regarding blood biochemical parameters between control group and quails treated with Cr(VI). Our results showed that hexavalent chromium had negative effects on biochemical parameters in quails, while treatment with Cr(III) showed minor fluctuations in concentrations or activities of blood biochemical parameters.

Integrated intelligent CAD systems (IICAD) can be developed for different purposes. The objective of this article is to emphasize the advantages of the use of IICAD systems in comparison with the classic systems. The article shows a structure of one such developed system, namely the IICADv system. This system is used for automatization of activities undertaken during the realization of certain phases of the process of designing of shafts, especially the synthesis phase. The development of a module for computation of the shaft and integration of the entire system was performed in the C# programming language, while shaping of the shaft was performed in the CATIA system. The interlinking was performed thanks to previously modelled basic 3D models. In such way, utilizing the advanced IICADv system, the computation and shaping of the shaft is done almost instantly. The results of the use of the IICADv systems are generated final 3D models of the shaft, ready for use by numerous other applications.