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Number of results: 31
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Abstract

A. B. Dobrowolski, a member of the Belgian expedition in Belgica to West Antarctica (1897-1899), after his return home became a strong supporter of Polish scientific activity in the Polar countries. His patronage - called by him the "Polar Action", was especially well marked during organization of three Polish expeditions to the Svalbard archipelago: to Bear Island during the 2nd Polar Year, 1932-33 and to Spitsbergen in 1934 and 1938. Apart from his scientific achievements in Antarctica, Dobrowolski was also widely known as an author of popular-scientific books on history of discovery and exploration in the Arctic and the Antarctic.
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Abstract

Cheerleading is a new sport, practiced in 110 nations; since 2016 enjoys provisional Olympic status. Its leaders claim that it is a “happy” sport, but research on its psychological effects is lacking. In this field-study we examined core-affect, positive-affect, and negative-affect in 65 cheerleaders before, during, after, and one-hour after a cheerleading training. Core-affect was more positive during and immediately after training, but it tapered off one hour following the training when feeling states were still more positive than at baseline. Negative-affect declined linearly from baseline to one-hour following training when it became significantly lower than its previous values. Positive-affect showed quadratic dynamics, in parallel with arousal, being higher during and immediately after training than during baseline, or one-hour after training. These results demonstrate for the first time that cheerleading is a “happy” sport, which apart from the skill-development also yields positive psychological emotions both during and after training.
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Abstract

In the era of an aging society, age friendly cities planning is gaining in importance. Due to the low mobility of these people, it is important to plan their immediate living environment, ensuring access to facilities and areas that meet the basic needs of this special group of urban space users. The paper analyzes the potential accessibility of older people to green areas, sports and recreation facilities, service and commercial facilities, culture and health care facilities, and public transport stops, in order to delimit problem areas characterized by functional and spatial deficits in this area. In addition, the level and quality of accessibility of older people to the abovementioned elements of development.
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Abstract

ll was proved that the activity of basic proteinases (pH 8.3) and acid proteinases (pH 4.0) of the Antarctic krill increases exponentially in spring-summer season (September-December); the activity of the first ones is 6 times higher and increases more rapidly. The positive relation between the proteolytic activity and the degree of gut filling of krill was also evidenced. The lack of high activity of acid proteinases in early spring does not support the suggestions of Ikeda and Dixon (1982) that during Antarctic winter krill takes energy from the autoproteolysis of own body proteins.
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Abstract

Seasonal changes in the Antarctic krill (Euphausia superba Dana) autoproteolytic activity were followed throughout the year. Using the kinetic formula for the first order reaction, the initial reaction rate (y0), the rate after 5 minutes (y5) and the average reaction rate (yx) after 0, 5, 10, 15 and 20 min of incubation of mixed homogenate at 40° + 0.2°C were determined in each sample. Changes in the krill autoproteolytic activity over the year were found to follow a sinusoid with a maximum during the austral summer (January) and a minimum during the austral winter (July-August). The maximum initial reaction rate was about ten times the minimum initial rate, which is an evidence of a considerable seasonal variation in the krill autoproteolytic activity associated presumably with the krill feeding intensity.
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Abstract

Physical and chemical properties (granulometric composition, pH, carbonates, organic carbon, nitrogen etc.) as well as bioenergetic activity of Spitsbergen tundra soils were studied at three chosen stations situated near Polish polar station "Hornsund". It was found that biological activity of Arctic tundra soils depended mainly on its physical properties, whereas the chemical composition of organic matter did not effect directly the bioenergetics of these soils. This bioenergetic activity depends mainly on the richness of micro- and mesofauna communities inhabiting the soil.
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Abstract

The complexity of the phenomena associated with the course of the cognitive processes that determine an efficient learning, excludes the possibility of collecting knowledge in other ways than neuronal-information. It excludes also possibilities of interpreting it, in other ways than with use of respectively formalized cognitive models. The presented paper is a kind of summary of the latest achievements in this field.
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Abstract

The underground mining of coal deposits in the Upper Silesian Coal Basin (GZW) re-sults in an imbalance in the distribution of the stress in the rock mass, both in the immediate and distant surroundings of mining excavations. The occurrence of seismic tremors, among others, is the consequence of this process,. The intensities of seismic phenomena, which occur in several regions of the GZW (Bytomian Basin, Main Saddle, Main Basin, Kazimierzowska Basin, and the Jejkowice Basin) are very diverse, ranging from tremors unrecognizable by humans to strong tremors of the nature of weak earthquakes (Patyńska and Stec 2017). During the period of 15 years, i.e. from 2001 to 2015, the level of seismic activity changed and de-pended on both the intensity of the excavation work and the variability of the lithological and tectonic structures. On the other hand, the seismic activity analysis has shown that in recent years, despite a decrease in total output, seismic activity and rockburst hazard have increased. One of the rea-sons was the increase in mining output. Almost half of the output came from coal seams under the rockburst hazard. This resulted in an increase in the number of great energy tremors with the energy of 107, 108 and 109 J. It has been shown that the amount of energy tremors has a high impact on the level of the rockburst hazard. Between 2001 and 2015, as many as 20 rockburst were caused by seismic tremors above 107 J with 42 total phenomena (Patyńska 2002–2016). The purpose of characterizing the causes of this phenomenon was determined by the parameters characterizing the structure of the rock mass in places where the rockburst was recorded.
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Abstract

On the basis of observations and markings of Weddell seals in the region of the Admiralty Bay it was estimated that numbers of this species decreased systematically from about 500 to about 100 individuals from December to February. The sex structure of the local population also changed, showing a growing domination of females. Males were observed more often on coastal snow patches, females prevailed on rocky beaches close to the sea. A thesis of an increased nocturnal activity of Weddell seal was confirmed, indicating also a possibility of a two days activity cycle of this species. Synchronized among the individuals of local populations by atmoshperic conditionds.
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Abstract

The article presents the results of tests of the application of magnetic fuel activators, which improve the efficiency of metallurgical furnaces and positively affect the ecological aspects of their work. Energy indicators for metallurgical furnaces during operation before and after installation of magnetic fuel activators as well as the results of composition and concentration of emitted pollutants are included in the paper. The magnetic activation of liquid and gaseous fuels modifies their structure. As a result of the activation, the fuel mixture is selectively saturated with oxygen in the zone of free fuel flow. The combustion conditions were close to optimal, which is confirmed by the reduction of pollutants in the exhaust gases. Fuel saving in the combustion process is also a measurable economic effect. The tests included ovens of several types: pusher furnace, one and two chamber furnaces and a furnace with a rotary shaft. Several-month measurement cycles were carried out on each of them. The experiments consisted in the analysis of gas and heat consumption per month in individual furnaces before and after the use of magnetic fuel activators. The effectiveness of using activators was determined on the basis of the results of the tests carried out. As a result of a twelve-month test cycle on the pusher type furnace, a 36% reduction in gas consumption and a 22% reduction in heat consumption were achieved. After a seventeen-month measurement cycle on chamber furnaces, a 35% reduction in gas consumption and 6% in heat consumption were achieved. The tests on furnaces with a rotary shaft lasted fourteen months and showed a reduction in gas consumption by 8%. An improvement in the composition of fumes in the furnace atmosphere was achieved in all units with magnetic activators installed, as well as a reduction in the emission of harmful pollutants into the atmosphere from the installation.
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Abstract

Activation of tyre pyrolysis char (TPC) can significantly increase its market value. To date, it has been frequently carried out in different reactors. In this work, thermogravimetric analysis was used instead. The performance of activated pyrolysis chars was tested by adsorption of acetone vapour and comparison of the equilibrium adsorption capacities for all samples. The highest equilibrium adsorption capacity was observed for the carbon burn-off of #24; 60%. In addition, the equilibrium adsorption capacity of activated TPC decreases by about 10% after eleven adsorption/desorption cycles. Moreover, activation changed the porous structure of pyrolysis chars from mesoporous to micro-mesoporous.
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Abstract

Ludwigite is the main available boron-bearing resource in China. In order to enrich the theory system and optimize its utilization processes, this paper study the mechanism and kinetics on non-isothermal decomposition of ludwigite in inert atmosphere by means of thermal analysis. Results show that, the decomposition of serpentine and szajbelyite is the main cause of mass loss in the process. At the end of decomposition, hortonolite and ludwigite are the two main phases in the sample. The average E value of structural water decomposition is 277.97 kJ/mol based on FWO method (277.17 kJ/mol based on KAS method). The results is proved to be accurate and reliable. The mechanism model function of structural water decomposition is confirmed by Satava method and Popescu method. The form of the most probable model function is G(α) = (1 – α)–1 – 1 (integral form) and f (α) = (1 – α)2 (differential form), and its mechanism is chemical reaction. This is verified by the criterion based on activation energy of model-free kinetics analysis.
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Abstract

It is estimated that the amount of used car tires in the European Union in 2016 was established at the level of 3,515,000 Mg, which is undoubtedly a problem from the point of view of engineering and environmental protection. An alternative to storing this waste in landfills is their pyrolysis. As a result of thermal decomposition, calorific value products (oil and gas fraction) are obtained, as well as a solid residue, which due to its composition and properties can be processed into a high quality carbon sorbent. For this purpose, various methods of modification of the pyrolyzate are used, both involving physical and chemical activation. This article presents the characteristics of solid residue after the pyrolysis of rubber tires running at a temperature of about 400°C, which included an analysis of chemical composition (XRF and IR), mineralogical composition (XRD, SEM-EDS) and textural characteristics. Additionally, for the purpose of activation, the sample was treated with nitrogen at a temperature of 550°C. The mineralogical analysis showed that the dominant mineral component is carbon. In addition, the presence of quartz, calcite and sphalerite was observed. Analysis of the chemical composition suggests that due to the high carbon content (about 80% by mass) it is possible for a carbon sorbent from the analyzed waste to be obtained. However, previous preliminary studies did not allow a material constituting a substitute for activated carbon to be obtained, because the applied modification only slightly increased the BET specific surface area, which reached the value of approx. 85 m2/g. Based on the analysis of the pore size distribution of the 2 tested samples, it was found to be homogeneous/modal with a micro/mesoporous nature, while the shape of the hysteresis loop suggests the presence of “bottle shape” pores. Due to the relatively high content of zinc, the composition of waste (about 4% of mass), the possibility of recovery of this element should also be considered.
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Abstract

The author shows the activity of the inhabitants in the process of revitalization which took place in Poznan at the turn of the 20. and 21. century. Overview of actions demonstrates the transformation of instruments and methods of conduct, but also is a presentation process of self-education of all participants: the associations, municipal authorities and residents. Relevant are also the examples of intentional educational and cultural initiatives addressed to the residents and held with residents in the framework of the Urban Renewal Program. Accumulation of these activities led to stimulate of civic awareness, neighborly relationship and local identification, but also initiated the transformation of individual mental. As a result, they developed a multi-threaded relationship: realization by the people of the right to co-decision and shared responsibility influences the attitudes of representatives of the local authorities and a kind of reciprocal social education, leaning to the subjective treatment of all participants of social processes.
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Abstract

In our previous Genome-wise Association Study we found that Cystic Fibrosis Transmem- brane Conductance Regulator gene (CFTR) is a candidate gene for sperm motility in fresh semen of Holstein-Friesian bulls. Since in cows thawed semen is commonly used for the artificial insem- ination (AI) we have decided to find out whether functional polymorphism within CFTR gene coding sequence is associated with selected parameters of thawed sperm, including their motility evaluated by computer-assisted sperm analysis (CASA), the activity of three antioxidant enzymes: glutathione peroxidase (GPx) catalase (CAT), superoxide dismutase (SOD), ATP con- tent and integrity of sperm membranes. One hundred twenty Holstein Friesian bulls kept in uni- form environmental conditions (one AI company) were included in the study. Significant associ- ations between genotypes of missense mutation within exon 11 of the CFTR gene (Met468Leu) and the activity of antioxidant enzymes and sperm mitochondrial function were revealed. No effect of CFTR genotypes on sperm motility was observed. Significant differences in CAT and SOD activity were found between AA and TT homozygous individuals. Bulls with TT genotype had the lowest activity of both antioxidant enzymes. The same bulls also showed the lowest num- ber of sperm with active mitochondria. Our results demonstrate that missense mutation Met468Leu within CFTR gene is associated with antioxidant enzyme activity and mitochondrial function of bovine thawed sperm without affecting their motility.
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Abstract

Effects of fermented extruded rye flour supplements with Lactobacillus sakei KTU05-6 or Pediococcus pentosaceus BaltBio02 on milk production and composition, as well as ruminal parameters, were determined in Lithuanian Black & White dairy cows. Also, determination of antimicrobial activities of tested lactic acid bacteria (LAB) against a variety of pathogenic and opportunistic bacterial strains previously isolated from diseased cattle was performed. The highest antimicrobial activity was demonstrated in L. sakei against S. aureus, and in P. pentosaceus against P. aeruginosa and S. aureus. The count of LAB in the supplements after 72 h of fermentation of extruded rye flour with L. sakei and P. pentosaceus was 9.6±0.4 log10 CFU/g and 9.5±0.3 log10 CFU/g, respectively. All cows (n=60) were fed the same basal diet. The treatment differences were achieved by individually incorporating (65 d.) one of the supplements: L. sakei KTU05-6 (group B; n=20) or P. pentosaceus BaltBio02 (group C; n=20). The control group A (n=20) was on the basal diet only. A supplement fermented with L. sakei does not have a significant influence on dairy cattle milk production and rumen fluid parameters. The type of LAB used has a significant influence (p<0.0001) on microbiological parameters of the rumen (TCM, TCL, TCE). The milk yield was increased (p≤0.05) using P. pentosaceus BaltBio02 supplement, and further research is needed to identify w hat is the main mechanism of the positive action.
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Abstract

Zinc is present in electric arc furnace dust (EAFD) mainly in two basic minerals, namely as franklinite ZnFe2O4 and/or zincite ZnO. While zincite is relatively reactive and easily treatable, franklinite is considerably refractory, which causes problems during EAFD processing. In this work EAFD containing 18.53% Zn was leached in water solution of ammonium carbonate. This leaching solution selectively leaches zincite, while franklinite is refractory and stable against leaching in this case. The temperature dependence of zinc leaching from EAFD was studied and the activation energy EA was determined by two methods: 1.) classically based on zinc chemical analyses from the leaching solution and 2.) by using of X-Ray diffraction qualitative phase analyses of leaching residues. The determined values of activation energies 37.41 and 38.55 kJmol–1 match perfectly, which show the excellent possibility of using X-Ray diffraction toward the study of leaching kinetics at properly chosen experimental conditions. The important result is the determination of the amount zincite and franklinite in EAFD, which is not possible by using of classical chemical methods.
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Abstract

The five-layer Aurivillius type structures with the general chemical formula Bi5Fe2-xMnxTi3O18, where x = 0, 0.6, 1.2 have been synthesized and tested. The SEM studies showed a significant increase in grain size in the manganese-modified Aurivillius type ceramic material (for x = 1.2). The increase in the amount of manganese ions (Mn3+) affects the decrease in the temperature at which the relaxation processes take place. Namely from 525 K (1 kHz) and 725 K (1 MHz) for BFT sample (x = 0) to 355 K (1 kHz) and 565 K (1 MHz) for BFM12T sample (x = 1.2). Using the Arrhenius’s law and the Vogel-Fulcher’s relationship the activation energy (Ea) and the relaxation time have been calculated. The value of Ea increases with the increase of the Mn amount from 0.737 eV (for x = 0) to 0.915 eV (for x = 1.2).
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Abstract

Nil strength temperature of 1062°C and nil ductility temperature of 1040°C were experimentally set for CuFe2 alloy. The highest formability at approx. 1020°C is unusable due to massive grain coarsening. The local minimum of ductility around the temperature 910°C is probably due to minor formation of γ-iron. In the forming temperatures interval 650-950°C and strain rate 0.1-10 s–1 the flow stress curves were obtained and after their analysis hot deformation activation energy of 380 kJ·mol–1 was achieved. Peak stress and corresponding peak strain values were mathematically described with good accuracy by equations depending on Zener-Hollomon parameter.
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Abstract

Fe-40wt% TiB2 nanocomposites were fabricated by mechanical activation and spark-plasma sintering of a powder mixture of iron boride (FeB) and titanium hydride (TiH2). The powder mixture of (FeB, TiH2) was prepared by high-energy ball milling in a planetary ball mill at 700 rpm for 3 h followed by spark-plasma sintering (SPS) at various conditions. Analysis of the change in relative sintered density and densification rate during sintering showed that a self-propagating high-temperature synthesis reaction occurs to form TiB2 from FeB and Ti. A sintered body with relative density higher than 98% was obtained after sintering at 1150°C for 5 and 15 min. The microstructural observation of sintered compacts with the use of FE-SEM and TEM revealed that ultrafine particulates with approximately 5 nm were evenly distributed in an Fe-matrix. A hardness value of 83 HRC was obtained, which is equivalent to that of conventional WC-20 Co systems.
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Abstract

Reduction of three industrial nickel oxides (Goro, Tokyo and Sinter 75) with a hydrogen bearing gas was revisited in the temperature interval from 523 to 673 K (250 to 400°C). A pronounced incubation period is observed in the temperature interval tested. This period decreases as the reduction temperature increases. Thermogravimetric data of these oxides were fitted using the Avrami-Erofeyev kinetic model. The reduction of these oxides is controlled by a nucleation and growth mechanism of metallic nickel over the oxides structure. Rate kinetic constants were re-evaluated and the activation energy for the reduction of these oxides was re-calculated.
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Abstract

Isothermal hot compression experiments were carried out using the Gleeble-1500D thermal mechanical simulator. The flow stress of the Cu-1%Zr and Cu-1%Zr-0.15%Y alloys was studied at hot deformation temperature of 550°C, 650°C, 750°C, 850°C, 900°C and the strain rate of 0.001 s–1, 0.01 s–1, 0.1 s–1, 1 s–1, 10 s–1. Hot deformation activation energy and constitutive equations for two kinds of alloys with and without yttrium addition were obtained by correlating the flow stress, strain rate and deformation temperature. The reasons for the change of hot deformation activation energy of the two alloys were analyzed. Dynamic recrystallization microstructure evolution for the two kinds of alloys during hot compression deformation was analyzed by optical and transmission electron microscopy. Cu-1%Zr and Cu-1%Zr-0.15%Y alloys exhibit similar behavior of hot compression deformation. Typical dynamic recovery occurs during the 550-750°C deformation temperature, while dynamic recrystallization (DRX) occurs during the 850-900°C deformation temperature. High Zr content and the addition of Y significantly improved Cu-1%Zr alloy hot deformation activation energy. Compared with hot deformation activation energy of pure copper, hot deformation activation energy of the Cu-1%Zr and Cu-1%Zr-0.15%Y alloys is increased by 54% and 81%, respectively. Compared with hot deformation activation energy of the Cu-1%Zr alloy, it increased by 18% with the addition of Y. The addition of yttrium refines grain, advances the dynamic recrystallization critical strain point and improves dynamic recrystallization.
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Abstract

In the current study, the hot deformation of medium carbon V-Ti micro-alloyed steel was surveyed in the temperature range of 950 to 1150°C and strain rate range of 0.001 to 1 s–1 after preheating up to 1200°C with a compression test. In all cases of hot deformation, dynamic recrystallization took place. The influence of strain rate and deformation temperature on flow stress was analyzed. An increase in the strain rate and decrease in the deformation temperature postponed the dynamic recrystallization and increased the flow stress. The material constants of micro-alloyed steel were calculated based on the constitutive equations and Zener-Hollomon parameters. The activation energy of hot deformation was determined to be 458.75 kJ/mol, which is higher than austenite lattice self-diffusion activation energy. To study the influence of precipitation on dynamic recrystallization, the stress relaxation test was carried out in a temperature range of 950 to 1150°C after preheating up to 1200°C. The results showed no a stress drop while representing the interaction of particles with dynamic recrystallization.
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Abstract

The most important item of city activity is to define development directions. Because of strategic character of this issue, a very important thing is inhabitants’ contribution in decision making. Cooperation between them and city authorities should lead to positive changes in the city and inhabitants’ life quality. They learn social engagement when taking part in determining of city development directions. Showing their creativity and building social relationships in city area. The aim of the paper was determining problems of participation in the describing of city development directions process. In the research there were used several methods: literature studies, logical construction, deduction and observations.
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