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The current issue of the Scientific Journal of Gdynia Maritime University contains publications of employees of the Faculty of Mechanical Engineering of the Gdynia Maritime University, the Joint Institute of Mechanical Engineering of the National Academy of Sciences of Belarus, the Admiral Makarov State University of Maritime and Inland Shipping in Russia, and the WBS University in Gdansk. The papers present the results of research that covers the field of engineering and technical sciences and address issues related to logistics.

The Journal presents issues related to new concepts of the increase of the efficiency of thermal circuits of steam turbines. Losses of circuit efficiency depending on the number of regenerative exchangers in the steam system are evaluated. Three different types of heat recovery regeneration exchangers that can be used in thermal circuits and their impact on the efficiency of the steam turbine system are described. The concept of internal superheating and the possibilities of increasing efficiency of the steam circuit as a result of its use are also presented.

The publication also recommends a technological pressing process with three innovative spindle pullers for chip-free finishing of the inner surface of a cylinder. The proposed treatment makes it possible to obtain the geometric structure of the surface required to ensure the tightness of the mating parts.

This issue of journal presents the results of numerical modelling using finite element method (FEM) software, such as MSC Software Patran and Abaqus.
The modelling was performed taking into account the beam geometry, the material properties, the boundary conditions, and the set load. In order to verify the model, a comparative analysis was performed of the values of the deflection of the beam’s central axis obtained from the empirical experiments and the values obtained using the FEM method.

The article presented by the employees of the Joint Institute of Mechanical Engineering of the National Academy of Sciences of Belarus concerns the influence of heat treatment of ‘Ni80Cr20 + Al99,3’ and ‘Ni80Cr20 + 08Mn2Si’ coatings applied supersonically using the arch method on their selected properties.
The authors demonstrated that annealing of the coatings results in an increase in microhardness and, consequently, in increased resistance to tribological wear.

Researchers from the WBS University in Gdańsk described the problems related to changes in the quality of frozen food due to its transport, from the point of view of the burden on the environment and the risk for the consumer. The paper presents physical, chemical, and microbiological threats to the quality of frozen food which are caused by conditions related to the logistics process. The author’s analysis of the factors that directly influence the safety of frozen food shows that the complex logistics process should be interpreted in a holistic way, starting from obtaining raw materials, through production of the product to its consumption. Integrity of the cold chain is an important feature that ensures the supply of safe food to consumers.

                                                                       Robert Starosta