This paper crowns efforts, made by its author, aiming in showing and proving that the current formula for calculation of the spectra of output signals at A/D converters requires a correcting factor in it. A number of partial results obtained and published in the last years are referred to here. They paved the way to a fully satisfactory and correct result; it is presented in this work. The corrected formula for spectrum calculation is derived using a description of the output signal of an A/D converter by means of the so-called Dirac comb, however not in a direct form, but with taking into account physical reality. In addition, the paper contains a number of interpretative remarks, comments, and explanations - clarifying those matters that have so far been omitted in analyses of the sampling process, despite the fact that they raised various types of doubts.

The acoustic effect of windows installed in a prefabricated wood frame façade was considered. Windows inserted into a lightweight wall modify its structural scheme. The research aimed to investigate the possible interaction of the façade’s main components and their actual contribution to the total sound insulation. The principal research question involved the prediction of the acoustic performance of the complete prefabricated panel from the performance of its basic elements, an opaque part and windows. As the frequency-dependent characteristics of the elements differ substantially, the use of single number values for prediction and accuracy was of particular interest. The study is based on laboratory measurements. Initially, two full-scale samples of an opaque wall and four windows were tested separately. Then, several variants of the façade consisting of various combinations of these elements were examined. The results of measurements were juxtaposed and compared with calculated values. The frequency-dependent experimental results were fairly consistent with calculations. The estimations based on single number quantities were also in good agreement with measurements. Thus, it may be concluded that the façade elements did not interact significantly, and the single number calculations give reliable results that can be used in practice.

The Fibre Bragg Grating (FBG) based temperature optical sensor has been designed and demonstrated. FBGs have been modelled and fabricated so as to convert the Bragg wavelength shift into the intensity domain. The main experimental setup consists of a filtering FBG and two scanning FBGs, respectively, left and right scanning FBG, whereby scanning FBGs are symmetrically located on the slopes of the filtering FBG. Such an approach allows for the modulation of power for the propagating optical signal depending on the ambient temperature at the scanning FBG location. A positive or negative change of power is determined by the spectral response of the FBG. Experimental research of the scanning FBGs’ sensitivities emphasized that the key issue is the filtering FBG. A different level of sensitivity could be achieved due to the spectral characteristic of the filtering FBG. Omitting advanced and high-cost devices, the FBG-based temperature sensor is presented. The FBG-based sensor setup could yield resolution of 1°C for the range of temperature 0.5°C to 52.5°C. The experimental study has been performed as a base for an easy-placed sensor system to monitor external parameters in real environment.

The aim of this study was to evaluate the possibility to predict outcomes of artificial insemi- nation (AI) in dairy cows based on in-line milk progesterone (P4) concentration. The research was carried out on the herd of loose housing 245 dairy cows of 2-4 lactations, with average milk yielding 11.000 kg per cow. Milk sampling, measuring, and recording of milk P4 concentration was carried out using the Herd Navigator (HN). The grouping was performed according to the following three indices: the first by reproductive condition – pregnant or not pregnant after AI, the second by P4 concentration from day 20 before AI to day 20 after AI, and the third by P4 concentration at AI time. There was a significant difference in P4 concentration in the group of pregnant cows from day 15 to day 9 before AI, and it was by 18.3% higher com- pared to that in the group of non-pregnant cows in the said period (p<0.01). The milk P4 concen- trations began to differ mostly from day 10 after AI. At that time, the average P4 concentration in the group of pregnant dairy cows was by 36.8% higher compared to that in the group of non-pregnant cows (p<0.01). A statistically significant difference between the ratio of the cows with high, medium, and low P4 concentration on days 20-16 before AI (p<0.01) was determined. The highest number of cows with up to 2-3 ng/ml P4 concentration became pregnant at the AI time.
In-line milk P4 records captured on day 10-15 before AI can be used to predict the proper for reproduction period. By P4 concentrations on day10 after AI, the ratio of pregnant cows in herd can be assessed.

Author’s aim is to highlight problems related to the course of regulatory processes in the structures of the living organism. In this research area the question arises what is the task of causal factors and mechanisms governing regeneration processes, including building new parts of the body. Despite the vast knowledge already gained in this field, the way to restore the functional regeneration of some structures of the organism is still to be discovered.

A dynamic economy contributes to the increase in the number of workers exposed to mechanical vibration caused by machines and transport equipment. As the means of transport are insufficiently recognised sources of mechanical vibrations, this article presents the results of whole-body and hand-arm vibration tests of 30 most common means of in-house transport. An analysis of vibration signals recorded at each workstation according to PN-EN 14253 and PN-EN ISO 5349 made it possible to determine the weighted values of components of directional vibration acceleration and the values of daily vibration exposure A(8).

In order to assess exposure to whole-body and hand-arm vibration at the tested workstations of in-house transport, indices of vibration hazard related to admissible values, the total evaluation index (developed in a previous study at CIOP-PIB) and a three-degrees scale for assessing exposure to vibrations were used. The assessment showed that the workstations were a major hazard. Vibration hazards at all those workstations were classified as either medium or high.

In experiments with short-pulse lasers the measurement control of the energy of the laser pulse is of crucial importance. Generally it is difficult to measure the amplitude of the pulses of short-pulse lasers using electronic devices, their response time being longer than the duration of the laser pulses. The electric response of the detector is still too fast to be directly digitized therefore a peak-hold unit can be used to allow data processing for the computer. In this paper we present a device which measures the energy of UV short (fs) pulses shot-byshot, digitizes and sends the data to the PC across an USB interface. The circuit is based on an analog peak detect and hold unit and the use of fiber optical coupling between the PC and the device provides a significant improvement to eliminate potential ground loops and to reduce conductive and radiated noise as well. The full development is open source and has been made available to download from our web page (http://www.noise.inf.u-szeged.hu/Instruments/PeakHold/).

This article aims to identify potential risk factors affecting the implementation and synchronisation of surveying and construction works during building and operation of roads. The task was executed on the basis of literature studies and experience. The article is an introduction to the research that has been conducted by the authors on the reasonably precise index of factors which one may deal with during the implementation of facilities of this type. The raised issue is crucial for financial and time reasons, but what is important in the roads construction - also for social ones, as prolonged traffic disruption adversely affects the environment.

Prof. Jerzy Jankowski passed away on 18th of August, 2020 and this paper brings back this outstanding scientist, one of the most influential geophysicists in Poland and an extraordinary man. Considered a prime architect in the development of the geomagnetic observations in Poland, Prof. Jankowski was a giant in geophysics covering a wide range of problems, from the cognition of the deep basement in Poland and Central Europe to the studies of earthquake precursors. Besides research Prof. Jankowski also offered his administrative services to the Institute of Geophysics of the Polish Academy of Sciences, among others being its director for more than 30 years and also to the Polish Academy of Sciences as the Head of the Division of Earth and Mining Sciences for nearly a decade. Prof. Jankowski received many significant honors during his life; internationally, he was recognized as a foreign member of the Finnish Academy of Science and Letters and Hungarian Academy of Sciences.