The paper presents the results of hydrothermal zeolitization of fly ash from hard coal combustion in one of the Polish power plants. The synthesis was carried out using various NaOH fly ash mass ratio (3.0, 4.0 and 6.0) and the effect of NaOH concentration in the activating solution on composition of synthesized sample was tested. The process was carried out under the following permanent conditions temperature: 90°C, time – 16 hours, water solution of NaOH (L)/fly ash (g) ratio – 0.025. In the studied fly ash the dominant chemical components were SiO2 and Al2O3, while the main phase components were mullite, quartz and hematite, and a significant share of amorphous substance (glass and unburnt organic substance). After hydrothermal synthesis, the presence of unreacted fly ash phases was found in the products, as well as new phases, the quality and quantity of which depend on the NaOH to fly ash mass ratio used for synthesis:
for ratio 3.0 – Na-LSX type zeolite and hielscherite,
for ratio 4.0 – Na-LSX type zeolite, hielscherite and hydrosodalite,
for ratio 6.0 – hydrosodalite and hielscherite.
The grains in all products of synthesis are poly-mineral. However, it was found that the new phases, overgrowing the unreacted phase components of fly ash, crystallize in a certain order. Hielscherite is the first crystallizing phase, on which the Na-LSX type zeolite crystallizes then, and the whole is covered by hydrosodalite. In the products of synthesis, the share of sodium-containing phases (the Na-LSX type zeolite and hydrosodalite) increases with the increasing concentration of NaOH in the solution used for the process.
The problem of of the use of fly ash still constitutes a research and exploration area for scientists. This is due to the fact that, 6,000,000 Mg of coal combustion by-products (CCB) are storage on landfills yearly in Poland alone. One of the potential directions of using fly ash is to use it as a substrate in hydrothermal syntheses of mesoporous materials (synthetic zeolites). Zeolites are aluminosilicates with a spatial structure. Due to their specific structure they are characterized by a number of specific properties among others molecular-sieve, ion-exchange and catalytic that can be used in engineering and environmental protection. So far, the synthesis has been carried out using coal combustion by-products such as fly ash or microsphere. The article analyzes whether separation from the fly ash of the appropriate fraction (below 63 μm) will affect the formation of zeolite grains. The syntheses were carried out using class F fly ash and the fraction separated from it, which was obtained by sieving the ash through a 63 μm sieve. Chemical (XRF) and mineralogical (XRD, SEM-EDS) analyzes were carried out for substrates as well as the obtained reaction products. In the case of substrates, the analysis did not show any significant differences between the ash and the separated fraction. However, in products after synthesis (Na-X zeolite with a small amount of Na-P1 zeolite, and small amounts of quartz and unreacted aluminosilicate glass - mullite) higher aluminum and sodium contents were observed from the separated fraction, with a lower calcium and potassium content. A small proportion of illite was observed on the diffraction curve of the zeolite from the fraction. Observations of grain morphology showed no differences in formation. Based on the conducted analyzes, it can be stated that, considering the economics of the synthesis process, the separation of fine fractions from the fly ash does not affect the quality of the synthesis process.
Self-control is a complex and multifaceted construct that can be regarded as an individual trait that follows its own developmental trajectory. In the presented study we used NAS-50 for the assessment of self-control in adolescents and young adults. Since the questionnaire has not been used before in underage participants we tested its reliability in adolescent and adult samples. We also investigated possible age and gender differences in self-control abilities as well as relations between NAS-50 and behavioral measures of cognitive control and impulsivity. Although the sample was quite small, the reliability of the questionnaire was similar to the results achieved by its authors. According to the predictions in the literature we did not find relations between NAS-50 and behavioral measures of cognitive control and impulsivity. We also did not observe significant age differences in the assessment of self-control abilities. The theoretical relevance of our results is discussed.
A new extraction process suitable for treating refractory CuCo2S4 under atmospheric pressure acidic leaching conditions was investigated. The effect of variables such as oxidant species, liquid-to-solid ratio, leaching time, oxidizing agent and mineral quality ratio, H2SO4 concentration, temperature and sodium chloride concentration on the extraction efficiency of Co, Cu and Fe from CuCo2S4 were investigated. Under optimal conditions including P80-P90 of the sample was d < 0.0074 mm, stirring speed of 400 rpm, leaching time of 8 h with sodium chlorate (NaClO3) and mineral quality ratio of 0.5, 2 mol/L H2SO4, liquid-to-solid ratio of 7, leaching temperature of 90°C and 4 mol/L sodium chloride. The leaching efficiency of Co, Cu, and Fe were nearly 97.08%, 100%, and 92.45%, respectively. Furthermore, the contents of cobalt and copper in leaching residue were all less than 0.4 wt.%, which satisfies the requirements of industrial production.
This study focused on the fatigue and corrosion fatigue of maraging steel 18Ni (250). The 18Ni (250) samples were tested for axial fatigue in air and 3.5% NaCl solution. The effects of loading frequency and stress ratio on the fatigue strength of 18Ni (250) were studied. In air, the loading frequency was 10 Hz, and the stress ratio was 0.5. However, three loading methods were used in the 3.5% NaCl solution: (i) the loading frequency of 1 Hz and stress ratio of 0.5; (ii) the loading frequency of 1 Hz and stress ratio 0.1, and (iii) the loading frequency 5 Hz and stress ratio 0.5. The corrosion fatigue strength of samples in the 3.5% NaCl solution was 63.3% lower than that of the samples in air. The fractures in the samples were observed after the test.
The article discusses little-known facts from the lives of two great representatives of the Silver Age of Russian philosophy – Nikolai Berdyaev and Sergei Bulgakov – referring to the period when both were ardent Marxists. It discusses the beginning of the academic career of both thinkers, the turn of the 19th and 20th centuries. In the archives of Karl and Luise Kautsky in Amsterdam (International Institute of Social History) there are two Berdyaev’s letters to Kautsky regarding polemics about Marx and Marxism, which unfolded between them after Kautsky’s decision to publish in the pages of Die Neue Zeit an article by Berdyaev “F.A. Lange and Critical Philosophy in Its Relation to Socialism” (1900). This correspondence has probably become the catalyst for Berdyaev’s transition from ‛orthodox’ to ‛critical’ Marxism. On the other hand, Bulgakov’s letters to Kautsky (and those of his wife, Helena Tokmakova, to Luisa Kautsky) refer to the time of a research internship of Bulgakov in Berlin in the years 1898–1900. He then met Kautsky and Bernstein families, and engulfed himself in theoretical problems of Marxism. The text of the speech is accompanied by a translation into Polish and provided with comments on two Berdyaev’s letters to Kautsky (February and May 1900).
The study analyzes the Ruthenian language of a remarkable bilingual print that appeared in the important Orthodox cultural center Ostrih in Church Slavonic and in Ruthenian “prosta mova” (“common language”) in 1607. It offers a critical evaluation of earlier studies and adds several new observations and theses.
The study analyzes the vocabulary of the Ruthenian “prosta mova” (“common language”) in a bilingual Ruthenian-Church Slavonic printed edition of 1607 (“Likarstvo na ospalyj umysl´´ čolovičyj” – “A Remedy for the Idle Human Mind”, translated by Demian Nalyvajko). We single out and discuss those lexical stems of the Ruthenian text that have no immediate equivalent in the early modern Polish language. Some of these stems belong to the Orthodox church terminology, others can be explained by the Church Slavonic original of the translation, still others demonstrate that Nalyvajko, like many other Ruthenian authors of that period, avoided certain Polish word stems despite the fact that his language is characterized by a plethora of marked Polonisms, and some of these avoided stems do occur in other Ruthenian texts of that period. Several markedly Ruthenian stems belong to the sphere of functional words.