The application of waste heat from exhaust gas of ship’s main engines has become widely practiced as early as in the 1930s. Thus the increase of ship’s overall efficiency was improved. Nowadays all newly built ships of the 400 gross tonnage and above must have specified energy efficiency design index, which is a measure for CO2 emissions of the ship and its impact on the environment. Therefore, the design of waste heat recovery systems requires special attention. The use of these systems is one of the basic ways to reduce CO2 emissions and to improve the ship’s energy efficiency. The paper describes the ship’s heating systems designed for the use of waste heat contained in the exhaust gas of self-ignition engines, in which the heat carriers are respectively water vapor, water or thermal oil. Selected results of comparative exergy analysis of simplified steam, water and oil heating systems have been presented. The results indicate that the oil heating system is comparable to the water system in terms of internal exergy losses. However, larger losses of exergy occur in the case of a steam system. In the steam system, a significant loss is caused by the need to cool the condensate to avoid cavitation in boiler feed pumps. This loss can in many cases cause the negative heat balance of ship during sea voyage while using only the exhaust gas boilers.

This paper presents a comparative study between the conventional PI (Proportional Integral) and backstepping controllers applied to the DFIG (Doubly Fed Induction Generator) used in WECS (Wind Energy Conversion System). These two different control strategies proposed in this work are developed to control the active and reactive power of the DFIG on the one hand, and to maintain the DC-link voltage constant for the inverting function on the other hand. This is ensured by generating control signals for two power electronic converters, RSC (Rotor Side Converter) and GSC (Grid Side Converter). In order to optimise the power production in the WT (Wind Turbine), an MPPT (Maximum Power Point Tracking) algorithm is applied along with each control technique. To simulate the effectiveness of the proposed controllers, MATLAB/Simulink Software is used, and the obtained results are analysed and discussed to compare PI and backstepping controllers in terms of robustness against wind speed variations and tracking performance in dynamic and steady states.

The aim of the article is to present the attestations of contemporary Polish surnames of Lithuanian origin which are absent from the dictionary of Lithuanian surnames (“Lietuvių pavardžių žodynas”, LPŽ), excerpted from the anthroponymic index card files that have been stored in the Lithuanian Language Institute in Vilnius and continually enlarged for several decades now. The files contain data excerpted from historical sources of the 16th to 19th centuries and consist of about 200,000 index cards (the actual number of excerpted anthroponyms is lower since some recur in various sources). Due to space limitations, generally only directly attested names have been included in the article, to the exclusion of those whose relationship with the researched name can be inferred rather than considered proven. Each listed attestation of an anthroponym (probably not in all cases an already established hereditary surname) is accompanied by information concerning its location and year (or time bracket), wherever available in the card index file. Given names or other details (e.g. the role of the person mentioned in documents, such as godmother in the data excerpted from baptismal registers) have only been included occasionally, if there was some reason to do so.