Search Results

You are looking at 1 - 10 of 18 items

  • Author: D. BOGDAN x
Clear All Modify Search


The aim of the work was to determine 241Pu activities in different components (water, plankton and fish) of the southern Baltic Sea ecosystem. Measurement of 241Pu in the samples was done indirectly by determining the increment in 241Am from the decay of the β-emitting 241Pu in samples collected 10–15 years after the Chernobyl accident.

Enhanced levels of 241Pu were observed in all analyzed Baltic samples. The highest 241Pu concentrations in fish were found in Perciformes: benthic round goby (0.863 ± 0.066 mBq/g ww) and pelagic perch (0.666 ± 0.001 mBq/g ww). Plutonium is also non-uniformly distributed in the organs and tissues of the analyzed fish; especially pelagic herring and cod as well as benthic flounder. Most of 241Pu in flounder, herring and cod is located in soft tissues, especially digestive organs (stomach, intestine, liver). The annual individual effective doses calculated on the basis of 241Pu concentrations in fish indicated that the impact of the consumption of 241Pu containing Baltic fish on the annual effective dose for a statistical inhabitant of Poland was very small.


As a result of the wide recognition of the importance of trust as an element related to the cooperation in a variable and hardly predictable environment, the trust was appreciated by management sciences. Thanks to the trust, the organisation can react quickly to changes in a complex and turbulent environment, in which it is necessary to develop new - adequate to the needs - products. In the context of the above, the research was commenced, whose execution was the condition of an attempt to answer the question: is the number of the products implemented by the manufacturer a derivative of trust built between him/her and his/her recipients? In the context of such a question, the main objective of the paper is an attempt to illustrate trust - created by the manufacturer - as an attribute promoting his/her implementation flexibility. The achievement of such an objective is possible thanks to a detailed case analysis of the selected implementation process, which confirms that good relationships between partners - as a result of the increase in production series - may imply a decrease in its unit costs, which leads to significant profits in the long term.


The article presents forms of cooperation and social benefits resulting from cooperation between universities and business practice. Basic kinds and directions of mutual relations arising from common areas of interest, possibilities, needs and conditions for the functioning of each side, have been presented. Solutions carried out by universities with the participation of business practice have been discussed. In case of business practice, potential areas of cooperation with schools and joint ventures in the area of R&D have been discussed.


The study presents evaluation of an open-pollinated progeny test of 21 selected plus trees from Slavonian pedunculate oak provenance in Croatia (in the central part of Drava river valley). The test was established in 1992 with two-year-old seedlings. Heights were measured at 5 to 13 years and diameters at breast height (DBH) at 10 to 13 years after sowing. Variances caused by the population within provenance effect were not significant during the studied period. In contrast, variance components caused by family effect were statistically significant, and ranged from 11.1 to 18.6% and from 2.2 to 10.6% for height and DBH respectively. Statistically significant variances caused by the family effect indicate that most of genetic variation of productive traits was within the studied populations. The estimated family mean narrow sense heritabilities varied from 0.62 to 0.78 and from 0.28 to 0.65, while individual heritabilities ranged from 0.48 to 0.80 and from 0.09 to 0.46 for height and DBH, respectively. Realised gain from the test and expected genetic gains by two possible methods of selection for the measured traits have been calculated for: i.) realised gain i.e. superiority of selected plus trees progenies over control plants (bulks from unselected trees within the provenance) ii.) individual within provenance mass selection of first generation plus trees at the same ages as those represented in studied trial and iii.) backward selection among first generation plus trees after open-pollinated testing. Estimated genetic gains indicate that the highest gain could be expected by backward selection among first generation plus trees after open-pollinated progeny testing (9.7 to 22.3% and 6.8 to 17.3% over control means). These results indicate that due to significant within population variation and high additive variances, improvement for productive traits in the studied oak populations could be achieved by use of seeds and plants from selected plus trees (especially from already established clonal seed orchard), at least in younger ages.


In the paper [1] assumptions for fatigue life calculations in the low- and high- cycle fatigue ranges of metal alloys, have been formulated. Three calculation methods: that expressed in stresses, strains and a mixed (stress-strain) one, have been there presented. In this paper results of fatigue life calculations of C45 steel performed in line with the above mentioned methods have been described, and their comparative analysis has been made. The calculations have been carried out for two-level and multi-level load programs of the varying parameters: maximum load within a load program and different values of spectrum filling factor. The comparative analysis of the results of fatigue life calculations in compliance with the above mentioned methods makes it possible to assess differences in the results and depenendence of the differences on values of load program parameters.


The paper presents the structure of a complex system for supporting a decision making process in machining data selection in turning operations. It is assumed, that the system modules cooperate with each other, utilize data and knowledge bases through the information bus. The system proposes to use on line information from visual monitoring module equipped with high speed camera what enables to observe chip forms. Particular modules and their tasks in the system are described as well as some examples are described.


In this work - in view of still decreasing crude oil resources and increasing fuel prices - are presented issues concerning research on development of other, alternative fuel sources including those used in water, land and air transport means. One of them is hydrogen which, while burning, does not produce noxious carbon dioxide but only side effects such as heat and clean water.

It is almost true that along with sudden drop of availability and rising price of crude oil many countries face economical paralysis. Any of alternative sources is not capable of supplying even only a basic amount of such energy, not mentioning the whole amount of energy demanded by our civilization. Hydrogen as an independent fuel for internal combustion engines has yet to go a long way to commercialization. to be Co-burning systems (combustion of mixtures)of today used hydrocarbon fuels combined with hydrogen seem closer to this aim. As proved in many investigations the substitution of a part of hydrocarbon fuel by hydrogen enables to make use of beneficial features of both the fuels.

One of possible solutions of the problem may be application of an innovative hydrogenic fuel electrolyzer which is presented and evaluated in this paper.