Properties of Polydisperse Tin-doped Dysprosium and Indium Oxides

The results of investigations of the complex permittivity, diffuse-reflectance, and characteristics of crystal lattices of tin-doped indium and dysprosium oxides are presented. Using the methods of spectroscopy and X-ray diffraction analysis, it is shown that doping of indium oxide with tin results in a significant increase of the components of the indium oxide complex permittivity and an appearance of the plasma resonance in its diffuse-reflectance spectra. This indicates the appearance of charge carriers with the concentration of more than 1021 cm−3 in the materials. On the other hand, doping of the dysprosium oxide with the same amount of tin has no effect on its optical and electromagnetic properties

Silicon nitride/carbon nanotube composites: preparation and characterization

This paper investigates the preparation of silicon nitride composites with multi-walled carbon nanotubes (MWCNTs). Samples containing 1–10 wt% MWCNTs were ultrasonically processed in non-aqueous suspensions, dried, pressed, and then subjected to non-pressure sintering at 1600 °C for 2 h. The preliminary results showed that the mixture of activated silicon nitride and covered MWCNTs could be sintered. The porosity of the obtained samples ranged from 0.27 to 36.94 vol.%. The microstructure was observed by scanning electron microscopy (SEM), and the mechanical properties (hardness and fracture toughness) were also determined. Good hardness values were obtained for samples prepared by sintering the mechanically activated precursor under a flowing nitrogen atmosphere using the lowest fraction of CNTs. Residual activator reduced the densification of the composites

Effect of Ultrasonic-Assisted Preparation of Powders on Synthesis of Rare Earth Zirconates

The aim of the research was to determine the effect of sonochemical treatments on homogenization of powders as well as phase composition and thermal stability of sinters. The compounds were prepared from Eu2O3 and ZrO2 powders, weighed in the mass ratio 1:1. Initially ultrasound treatment was applied. 750-Watt ultrasonic processor VCX-750 equipped with sealed converter VC-334 and horn 630-0219 with the diameter of 13 mm (Sonics & Materials, Inc.) was used as a source of ultrasound. Applied ultrasound frequency was 20 kHz, power density was controlled in the range from 75 W/cm2 to 340 W/cm2. Investigated compounds were synthesized via solid-state reaction (SSR). The Differential Scanning Calorimetry (DSC) was used in order to investigate the effect of sonochemical treatment on the synthesis of prepared mixtures the powders particle size distribution was analyzed. Ultrasound treatment what wasn’t never been reported before

Solid State Synthesis of Europium Zirconate Based Material

In the article, the characterization of the microstructure, phase composition and distribution of elements in the Eu2 O3 -ZrO2 sintered materials obtained by four different ways of powders’ homogenization (mixing) process and different temperature of sintering process is shown. The feedstock powders with an average mole ratio of ZrO2 to Eu2 O3 equal 74% to 26% were used as an initial material. The principal aim of the investigation was characterization of differences in the microstructure of the same type of ceramics, however, prepared via different mixing and manufacturing processes. The range of the investigation covered a characterization of these materials via phase identification of all samples by XRD (X-ray diffraction) and characterization of internal morphology of the specimens with detailed analysis of elements distributions by SEM (scanning electron microscopy) and EDS (energy dispersive spectrometry). The aim of the following investigation is to characterize the possibilities of the solid state synthesis of the europium zirconate based materials, dedicated for TBC applications

Synthesis and Thermal Properties of Europium-Cerium Oxide as a New Fluorite-Type Ceramic Material for Thermal Barrier Coatings Applications

In the present paper the structure and thermal properties of europium cerium oxides were investigated. The material for the research was obtained via solid state synthesis. The initial powders: ceria CeO2 and europia Eu2O3 were mixed in 1:1 mass ratio (non-stoichiometric proportion with the excess of CeO2) and milled. The sintering process was performed using high temperature vacuum press at 1350°C. Calorimetric analysis was conducted both for initial powders and milled mixture. The structure, phase composition and thermal diffusivity of obtained material were investigated in as-sintered condition. It was revealed that the obtained material was multi-phase. Non-stoichiometric phases including Ce0.5Eu0.5O1.75 with fluorite type structure and different lattice parameters were present. Thermal diffusivity decreased in the range from 25 to 900°C from 1.49 to 0.57 mm2 /s and then increased to 0.70 mm2 /s at 1400°C

Synthesis and Thermal Properties of Cerium-Dysprosium Oxide

The paper presents results of investigation on synthesis and characterization of cerium-dysprosium oxide. The input powders - dysprosium oxide Dy,sub>2O3 and cerium oxide CeO2 - were mixed so as to obtain equimolar ratio of cations, milled in alcohol and synthesized via solid state reaction process at 1350°C under 15MPa in vacuum for 2h. The microstructure, phase composition and thermal properties were analyzed. The obtained material was multiphase. Non-stoichiometric compounds were identified. Thermal diffusivity of investigated material decreased in the temperature range of 25-1000°C from 0,71 to 0,45 mm2/s

Synthesis and Characterization of Thermal Properties of Type Eu2O3-ZrO2 Sinters

The oxides with pyrochlore or defected fluorite structure are a potential alternative ceramic materials for now widely used yttria-stabilized zirconia 8YSZ in the application for the insulation layer of thermal barrier coatings systems. This paper presents a procedure of synthesis of europium zirconate of Eu2Zr2O7 type, by the method of high temperature sintering under pressure. The analysis of the effect of the powders` homogenization methods on homogeneity of final sintered material showed that the highest homogeneity can be obtained after mechanical mixing in alcohol. Moreover, the DSC investigation carried out on a mixture of powders before the sintering process and on the material after high temperature sintering under pressure, suggest the synthesis of a new phase an europium zirconate Eu2Zr2O7 with the pyrochlore structure. Obtained phase was characterized by stability over the entire range of tested temperature, i.e. to 1450°C. The resulting material based on europium zirconate has a lower coefficient of thermal diffusivity than the now widely used 8YSZ

Wpływ 2-godzinnego wysiłku fi zycznego w mechanizmie treningu tańca orientalnego na zmiany wybranych wskaźników morfologii krwi

Introduction: Movement in combination with music, i.e. dance, is one of the most popular types of physical activity at all ages. Dance is a form of activity that differs in style and technique, and thus, energy consumptions during training are different. Under the name of oriental dance one can find: folklore, religious, ritual and popular dances that are associated with everyday life. In Polish and international literature on the subject, there are no studies in which changes in blood morphological properties of dancers practicing oriental style dance would be demonstrated. The results of laboratory tests published so far rarely describe the effect of dance on morphological blood indices, in addition, they are results for styles other than oriental dance. Study aim: The objective of the study was to demonstrate the effects of 2-hour physical exercise using the mechanism of oriental dance training on changes in selected quantitative indices of blood morphology in a group of young women. Materials and methodology: The study group consisted of 12 young women between the age of 20 and 35, with the average of 26.4±0.52 years, training oriental dance. Blood tests were performed twice: before and after the 2-hour workout. The dancers practiced a variation of oriental dance called shaabi, a high-intensity dance with a lot of jumping figures. Results: Analysing the average values of morphological indices before and after oriental dance training showed a statistically significant increase in WBC [109/L] by 23.28% and a decrease in RBC [10¹²/L] by 1.29%, HGB [g/L] by 1.00% and HCT [L/L] by 1.22% in the study group after the 2-hour oriental dance training session. Conclusions: The applied training influenced the results of blood indices in dancers participating in the study. Physical activity carried out in the form of dance causes quantitative changes in morphological blood indices.Wprowadzenie: Ruch w połączeniu z muzyką, czyli taniec jest jednym z najbardziej popularnych rodzajów aktywności fizycznej w każdym wieku Taniec jest formą aktywności, która różni się pod względem stylu i techniki, a co za tym idzie inne jest zużycie energii podczas treningu. Pod nazwą tańca orientalnego kryją się zarówno tańce folklorystyczne, religijne, obrzędowe jak i popularne, które są związane z codziennym życiem. W piśmiennictwie polskim i międzynarodowym nie ma badań wykazujących zmiany we właściwościach morfologicznych krwi u tancerek ćwiczących styl orientalny. Dotychczas opublikowane wyniki badań laboratoryjnych rzadko opisują wpływ tańca na wskaźniki morfotyczne krwi, w dodatku są to wyniki dotyczące innych stylów tanecznych niż taniec orientalny. Cel badań: Celem pracy było wykazanie wpływu 2-godzinnego wysiłku fizycznego w mechanizmie treningu tańca orientalnego na zmiany wybranych wskaźników ilościowych morfologii krwi w grupie młodych kobiet. Materiał i metodyka: Grupę badaną stanowiło 12 młodych kobiet w wieku od 20 do 35 roku życia z jego średnią 26.4±0.52 lat, trenujących taniec orientalny. Badania krwi przeprowadzano dwukrotnie: przed rozpoczęciem i po zakończeniu 2-godzinnego treningu. Tancerki ćwiczyły odmianę tańca orientalnego o nazwie shaabi, tańca o wysokiej intensywności wysiłku z dużą ilością figur skocznych. Wyniki: Analizując średnie wartości wskaźników morfologicznych przed i po treningu tańca orientalnego wykazano statystycznie istotne zwiększenie WBC [109/L] o 23,28% oraz zmniejszenie RBC [10¹²/L] o 1,29%, HGB [g/L] o 1,00%, HCT [L/L] o 1,22% w grupie badanej po 2-godzinnym treningu tańca orientalnego. Wnioski: Zastosowany trening wpłynął na wyniki morfologii krwi u tancerek biorących udział w badaniu. Aktywność fizyczna realizowana w formie tańca powoduje zmiany ilościowe wskaźników morfologicznych krwi

Synthesis and Characterization of Thermal Properties of Type Eu2O3-ZrO2 Sinters

The oxides with pyrochlore or defected fluorite structure are a potential alternative ceramic materials for now widely used yttria-stabilized zirconia 8YSZ in the application for the insulation layer of thermal barrier coatings systems. This paper presents a procedure of synthesis of europium zirconate of Eu2Zr2O7 type, by the method of high temperature sintering under pressure. The analysis of the effect of the powders` homogenization methods on homogeneity of final sintered material showed that the highest homogeneity can be obtained after mechanical mixing in alcohol. Moreover, the DSC investigation carried out on a mixture of powders before the sintering process and on the material after high temperature sintering under pressure, suggest the synthesis of a new phase an europium zirconate Eu2Zr2O7 with the pyrochlore structure. Obtained phase was characterized by stability over the entire range of tested temperature, i.e. to 1450°C. The resulting material based on europium zirconate has a lower coefficient of thermal diffusivity than the now widely used 8YSZ