Ship management is a topic that has rarely been approached in the modern Polish maritime legal sciences. There are numerous reasons behind the present state of affairs but it seems that the foremost one is, that the focus in political, legal and economic discourse is still on the legal aspects of ship ownership. This trend continues despite the fact that today over 73% of world shipping tonnage is managed by the specialized ship management entities. An economic analysis has proven that year after year Poland was ceasing to be a large ship owning nation, it used to be, and that this trend is unlikely to be reversed in the short and mid-term perspective. Poland may, however, still continue to play a vital role in the world of shipping by becoming a ship management centre. This article aims to introduce the Readers to the selected aspects of ship management operations.
The paper presents the summary of research on polymer melt particle motion trajectories in a disc zone of a screw-disk extruder. We analysed two models of its structure, different in levels of taken simplifications. The analysis includes computer simulations of material particle flow and results of experimental tests to determine the properties of the resultant extrudate. Analysis of the results shows that the motion of melt in the disk zone of a screw-disk extruder is a superposition of pressure and dragged streams. The observed trajectories of polymer particles and relations of mechanical properties and elongation of the molecular chain proved the presence of a stretching effect on polymer molecular chains.
In recent time, as the Chinese consumption level increases, the consumption quantity of high-value fruits, vegetables and seafood products have been increasing year by year. As a consequence, the traffic volume of refrigerated products also increases yearly and the popularization degree of the cold-chain transportation enhances. A low-temperature environment should be guaranteed during transportation, thus there is about 40% of diesel oil should be consumed by the refrigerating system and the cold-chain transportation becomes very costly. This study aimed to explore methods that could reduce the cost of transport packages of refrigerated products. On the basis of the heat transfer theory and the fluid mechanics theory, the heat exchanging process of corrugated cases during the operation of refrigerating system was analyzed, the heat transfer process of corrugated cases and refrigerator van was theoretically analyzed and the heat balance equation of corrugated cases was constructed.