Celestite in the Weathering Crust on Limestone Exposed to an Urban Atmosphere in Cracow (Poland)
Celestite containing very low amounts of barium occurs in weathering reaction zones developed on the Pińczów limestone exposed to the polluted atmosphere of Cracow. The mineral occurs both in limestone pore spaces filled with gypsum and in black gypsum crust. The Pińczów limestone contains ca 500 ppm strontium which was released during the reaction with atmospheric pollutants. The nucleation and growth of celestite, requiring significant concentration of components in evaporating solutions, is associated with gypsum crystallization.
Xenotime-(Y) veins in a Neoproterozoic metamudstone (Małopolska Block, S Poland)
First occurrence of xenotime-(Y) veins in the Neoproterozoic metamudstone, NW margin of the Małopolska Block, is reported here. The veins are <5 μm thick, inhomogeneous and of varied morphology. Their textural characteristics, exhibiting very low U and Th contents (<1 wt%) and relatively high heavy rare earth elements (REE) contents (12-24 REE2O3 wt%), suggest hydrothermal genesis, though diagenetic precursors of the veins are not excluded. The veins provide good evidence of the mobility of Y, REE, U and Th in low-temperature conditions (anchimetamorphic to greenschist facies). The observed differences in the chemical composition of the veins may indicate multiple stages of formation, possibly during several hydrothermal events that affected the area.
Statistical Approach to the Transformation of Fly Ash into Zeolites
The experimental conversion of F-class fly ash into zeolites is described. The ash, composed mainly of aluminosilicate glass, mullite and quartz, was collected in the Cracow power plant (southern Poland). The experiments involved the heating of fly ash samples in PTFE vessels. Time, temperature and solution composition were the reaction parameters considered in the experiments and in the subsequent modeling. A series of reactions with 0.5, 3 and 5M NaOH solutions (and some with additional 3M NaCl) were carried out at 70°, 100° and 150°C for 12-48 hours under autogenic pressure (not measured) and at a constant ash-to-solution ratio of 33.3 g/l. The following zeolite phases were synthesized: sodalite (SOD structure), hydroxysodalite (SOD), CAN type phases, Na-X (FAU), and NaP1 (GIS). Statistically calculated relationships based on the mineral- and chemical compositions of the reaction products support the conclusion that the type of zeolite phase that crystallizes depends on the concentration of OH- and Cl- in solution and on the temperature of the reaction. The duration of reaction, if on the order of tens of hours, is of less significance. The nature of the zeolite phase that crystalises is controlled by the intensity and selectivity of the substrate dissolution. That dissolution can favour, in sequence, one or other of the components in the substrate, resulting in Si/Al variation in the reaction solutions. Mullite dissolution (decreasing solution Si/Al) characterizes the most advanced reaction stages. The sequence of crystallization of the zeolite phases mirrors the sequential dissolution of substrate components, and the composition of the crystallizing zeolite crystals reflects the changes in the solution Si/Al.
Ash samples from biomass combustion or co-combustion with coal were analysed. The aim of this study of ash was to determine its mineral and chemical composition, and the chemical composition of solutions obtained during one-step water extraction. Besides the chemical analysis, X-ray diffraction (XRD) and scanning electron microscopy coupled with energy dispersive spectrometry (SEM-EDS) were applied.
The mineral and chemical composition of ash samples differ strongly. The content of heavy metals in the ash is generally low, but in some samples the limits of the content of some elements determined for fertilizers or soil amendments are exceeded. The relatively poor correlation between the concentration in leachate and bulk content in ash indicates that numerous elements are present in different forms in the studied samples. The results indicate that the potential use of biomass ash, or ash from biomass–coal co-combustion, requires complex studies that explore ash and leachates.
Introduction. Since mountain biking involves exercise of varying intensity, competitive performance may be affected by the rate of recovery. The aim of the current study was to determine whether maximal oxygen uptake is associated with the rate of heart rate and oxygen uptake recovery in mountain bike athletes.
Material and methods. The study examined 29 mountain bikers, including members of the Polish National Team. These athletes specialised in cross-country Olympic (XCO) racing. After undergoing a graded stress test on a cycle ergometer, the subjects were divided into two groups: G1, consisting of athletes with higher aerobic capacity (n = 12; VO2max > 60 ml∙kg−1∙min−1), and G2, comprising athletes with lower aerobic capacity (n = 17; VO2max < 55 mL∙kg−1∙min−1). Heart rate and oxygen uptake recovery was measured after the graded stress test in a sitting position.
Results. HRmax values did not differ significantly between the two groups. HR1’, HR2’, and HR4’ values recorded for G1 were statistically significantly lower compared to those achieved by G2. %HR1’, %HR2’, %HR4’, and %HR5’ values were also significantly lower in G1 than in G2. No significant differences were found in oxygen uptake during recovery (VO2-1’, 2’, 3’, 4’, 5’) between the two groups. Significantly lower %VO2max-1’, %VO2max-2’, and %VO2max-5’ values were observed in G1 compared to those in G2. No significant correlations were found between VO2max per kilogram of body mass and the recovery efficiency index in either group. There was, however, a statistically significant correlation between VO2max and the recovery efficiency index (R = 0.52) in the entire group of athletes (n = 29).
Conclusion. The study showed that the work capacity of mountain bike athletes was associated with the rate of heart rate and oxygen uptake recovery.
Introduction. So far there have been few studies on the effect of interval training with active recovery aimed at increasing aerobic power on the physical capacity of long-distance runners. Unlike standard interval training, this particular type of interval training does not include passive rest periods but combines high-intensity training with low-intensity recovery periods. The aims of the study were to determine the effect of aerobic power training implemented in the form of interval training with active recovery on the physical capacity of amateur long-distance runners as well as to compare their results against those of a group of runners who trained in a traditional manner and only performed continuous training.
Material and methods. The study involved 12 recreational male long-distance runners, who were randomly divided into two groups, consisting of 6 persons each. Control group C performed continuous training 3 times a week (for 90 minutes, with approximately 65-85% VO2max). Experimental group E participated in one training session similar to the one implemented in group C and additionally performed interval training with active recovery twice a week. The interval training included a 20-minute warm-up and repeated running sprints of maximum intensity lasting 3 minutes (800-1,000 m). Between sprints, there was a 12-minute bout of running with an intensity of approximately 60-70% VO2max. The time of each repetition was measured, and the first one was treated as a benchmark in a given training unit. If the duration of a subsequent repetition was 5% shorter than that of the initial repetition, the subjects underwent a 15-minute cool-down period. A progressive treadmill test was carried out before and after the 7-week training period. The results were analysed using non-parametric statistical tests.
Results. VO2max increased significantly both in group E (p < 0.05; d = 0.86) and C (p < 0.05; d = 0.71), and there was an improvement in effort economy at submaximal intensity. Although the differences were not significant, a much greater change in the post-exercise concentrations of lactate and H+ ions was found in group E.
Conclusions. The study showed that interval training with active recovery increased VO2max in amateur runners with higher initial physical capacity and stimulated adaptation to metabolic acidosis more than continuous training.
During single particle analysis of aerosol in Kraków (Poland) we noticed a new component, that is, aggregates of TiO2 particles. These aggregates are from 0.5 to 4 μm and are composed of individual particles whose size typically varies from between 100 and 350 nm. Smaller particles (below 100 nm) also occur. TiO2 particles are relatively abundant in the summer. The size distribution of the particles corresponds to “pigmentary” TiO2, which indicates that they could be derived from paints and building materials. TiO2 particles were not previously identified in aerosol samples in Kraków, and therefore this phenomenon is likely to be related to the common usage of new building materials and paints. A review of the literature suggests that TiO2 particles, especially within the nanosize range, could result in health and environmental impacts; however, evaluation of the actual threat is difficult.
The recovery of valuable metals from metallurgical slag disposals is a promising option to protect natural resources, limited due to technology development and increased consumption. The Ad-hoc Working Group on Defining Critical Raw Materials within the Raw Materials Supply Group has proposed a list of critical elements which have the greatest economic importance and meet the requirements of sustainable development in Europe. The goal of this study was to examine steelmaking- and blast-furnace slags from metallurgical processes to determine concentrations of elements of the greatest criticality for Poland, e.g. Nb, Ta and REE, and to discuss the viability of their recovery. Slag analyses indicate enrichment of REE relative to UCC, NASC and average chondrite compositions in blast-furnace slags and Nb and Ta in steelmaking slags. To make recovery of these critical elements reasonable and profitable, it is recommended that they be recovered together with other useful raw materials.