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Open access

Andrzej Pukacz, Małgorzata Oszkinis-Golon and Marcin Frankowski

Abstract

In the vegetation seasons 2016–2017, a survey of 30 pit lakes localized in the eastern part of the Muskau Arch (Western Poland) was carried out. The aim of the study was to characterize the habitat conditions of the selected lakes, based on the physico-chemical water characteristics. We hypothesized that the age and genesis of pit lakes are the main factors responsible for their hydro-chemical diversity. Therefore, in each of the lakes 27 physico-chemical parameters and chlorophyll a were measured in the water surface, in the peak of the vegetation season (July–August). Additionally, they were described in terms of genesis, origin and age. The results showed that the investigated lakes display a high diversity of habitat conditions reflected in varied physico-chemical water properties (significant lake-to-lake differences). The parameters mostly responsible for the differences were: Secchi depth (transparency), pH, EC, colour, hardness, TP, TN, TC, Ca2+, Mg2+, Fe, Al, Mn, S and Chl a. The comparison of the type of excavated aggregate showed significant differences for four parameters only. Much greater differences were found for the genesis of lakes (mining method) – 15 of the 28 analysed parameters significantly differentiated the lakes. Further analysis showed that half of the studied parameters were significantly correlated with the age of the pit lakes. Our results suggest that in addition to natural changes, secondary human-caused transformations (mostly neutralization and fertilization of the water) were among the key factors responsible for the differentiation of the lakes.

Open access

Piotr Szyczewski, Marcin Frankowski, Anetta Zioła-Frankowska, Jerzy Siepak, Tomasz Szyczewski and Paweł Piotrowski

Abstract

Vegetable oils belong to a large group of substances consumed on a daily basis. World vegetable oil production is soaring, reducing the popularity of animal fats. Heavy metals pose a threat to human health. It is estimated that about 80% of the daily dose of heavy metals enters the human body through the consumption of food. Hence, it is necessary to monitor their concentrations in food products. Besides, the presence of heavy metals is thought to have possible negative influence on the quality of oils, especially on their taste and smell. Heavy metals may also accelerate the process of the rancidifiction of oils. Rapeseeds, soybean seeds and linseeds were selected for the analysis because they are one of the most popular oilseeds and at the same time they differ in terms of growing conditions. The analyses of different fractions and the ready-made product were also performed. The aim of the study was to determine the variation in concentrations of heavy metals, iron and manganese in different fractions during production. The significant concentrations of iron, manganese and zinc were observed in oilseeds. It was also shown that during different stages of oil refining the concentrations of metals decrease. The concentrations of metals are compared with those reported in literature.

Open access

Robert Frankowski, Dariusz Chaberski, Marcin Kowalski and Marek Zieliński

Abstract

Most systems used in quantum physics experiments require the efficient and simultaneous recording different multi-photon coincidence detection events. In such experiments, the single-photon gated counting systems can be applicable. The main sources of errors in these systems are both instability of the clock source and their imperfect synchronization with the excitation source. Below, we propose a solution for improvement of the metrological parameters of such measuring systems. Thus, we designed a novel integrated circuit dedicated to registration of signals from a photon number resolving detectors including a phase synchronizer module. This paper presents the architecture of a high-resolution (~60 ps) digital phase synchronizer module cooperating with a multi-channel coincidence counter. The main characteristic feature of the presented system is its ability to fast synchronization (requiring only one clock period) with the measuring process. Therefore, it is designed to work with various excitation sources of a very wide frequency range. Implementation of the phase synchronizer module in an FPGA device enabled to reduce the synchronization error value from 2.857 ns to 214.8 ps.