The presented paper contains the results of research aimed at developing optimal strategies for controlling the feed rate in the friction drilling process. In particular, the use of linear variable feed rate for individual drilling stages and adaptive feed rate control have been tested. The experiments were carried out with the use of a CNC machine tool equipped with an axial force and torque sensor. Correlation between thrust force and torque was shown, respectively, in relation to the feed drive load and the drive of machine tool spindle. Based on this, a feed rate sensorless control strategy was created to protect against excessive and long-term overload both of the tool and the drives. The following assessment criteria were considered: drilling cycle time, maximum values of thrust and torque, maximum values of feed drive load and drive of machine tool spindle, maximum power and energy effect in the form of work necessary to perform during the drilling process and forming the hole flange. The obtained test results, made for low-carbon steel with a tungsten carbide tool, indicate the advantage of the approach based on the linear variable feed rate and adaptive control over the traditional drilling process based on the step change of the feed rate, according to the recommendations given by the tool manufacturers.

Bigamy, interpreted as entering into marriage by a person who is already married, is a phenomenon which can be analyzed on a number of different levels. One of the areas of the analysis is the area of penal law where bigamy is perceived as a crime against values such as proper functioning of family. Regulations of civil law concerning conclusion of marriage, declaring its non-existence and validity are relevant in context of realization of features of prohibited act created by Polish legislator in Article 206 of the Penal Code. Recognition of monogamy as the only permissible form of marriage is based, according to many authors, on the Constitution of the Republic of Poland. However, how is criminalization of bigamy justified on the area of axiology? How is bigamy perceived by legislation of the Catholic Church? In which way regulations of the Family and Guardianship Code affect realization of features of the crime from Article 206 of the Penal Code? The aim of this article is to seek an answer to the question why the legislator decided to criminalize bigamy. It is also a try to point out issues raised during the analysis of this subject in different areas of law, which are often disputed. Authors try to highlight the influence of the European and Judeo-Christian traditions on legislation in matter of bigamy.

The results of the research, which aimed to analyze the acoustic properties of selected sacred buildings located in the city of Częstochowa, Poland are presented in the paper. Three architecturally unusual and completely different from each other churches were selected for the study. The churches differed in shape of their buildings, cubic volume, years of construction, interior furnishings, etc. Nine different objective parameters were used to describe the physical properties of acoustical field in the studied churches. Various factors characterizing the acoustic properties of each building were determined, such as the distribution of sound pressure level (SPL), reverberation time T30, definition D50. Next, they were thoroughly analyzed, so as to ultimately obtain distributions of individual acoustic parameters in the space of the tested building. It allowed to evaluate the quality of the received verbal or musical message depending on the place where the listener was. Further research on speech intelligibility and the musical quality of churches was performed by determining the averaged values of next four objective acoustic parameters: centre time Ts, speech clarity C50, music clarity C80, and speech transmission index (STI). A new approach to analyzing the objective physical parameters describing the sound field was presented in Sec. 4. Mean free path length and critical distance were determined for the investigated acoustic fields in each church and they were associated with a general geometric factor characterizing the complexity of the room shape. The final part of the work presents a comparative analysis of the obtained results of acoustic quality tests of the temples, and thus their usefulness in terms achieving a maximum intelligibility of speech and music. The interesting similarities were found in the spatial distribution of individual acoustic parameters characterizing the distribution of the acoustic field in temples with completely different architecture.